The authors developed and validated the Watts Connectedness Scale (WCS), a three‑dimensional measure of felt connectedness to self, others and the wider world that demonstrated a stable factor structure and good internal consistency. WCS scores rose significantly after psychedelic experiences—correlating with mystical, emotional‑breakthrough and communitas measures—and increased more after psilocybin therapy than escitalopram in a randomised controlled trial, indicating sensitivity to therapeutically relevant change.
Rationale
A general feeling of disconnection has been associated with mental and emotional suffering. Improvements to a sense of connectedness to self, others and the wider world have been reported by participants in clinical trials of psychedelic therapy. Such accounts have led us to a definition of the psychological construct of ‘connectedness’ as ‘a state of feeling connected to self, others and the wider world’. Existing tools for measuring connectedness have focused on particular aspects of connectedness, such as ‘social connectedness’ or ‘nature connectedness’, which we hypothesise to be different expressions of a common factor of connectedness. Here, we sought to develop a new scale to measure connectedness as a construct with these multiple domains. We hypothesised that (1) our scale would measure three separable subscale factors pertaining to a felt connection to ‘self’, ‘others’ and ‘world’ and (2) improvements in total and subscale WCS scores would correlate with improved mental health outcomes post psychedelic use.
Objectives
To validate and test the ‘Watts Connectedness Scale’ (WCS).
Methods
Psychometric validation of the WCS was carried out using data from three independent studies. Firstly, we pooled data from two prospective observational online survey studies. The WCS was completed before and after a planned psychedelic experience. The total sample of completers from the online surveys wasN = 1226. Exploratory and confirmatory factor analysis were performed, and construct and criterion validity were tested. A third dataset was derived from a double-blind randomised controlled trial (RCT) comparing psilocybin-assisted therapy (n = 27) with 6 weeks of daily escitalopram (n = 25) for major depressive disorder (MDD), where the WCS was completed at baseline and at a 6-week primary endpoint.
Results
As hypothesised, factor analysis of all WCS items revealed three main factors with good internal consistency. WCS showed good construct validity. Significant post-psychedelic increases were observed for total connectedness scores (η2 = 0.339,p < 0.0001), as well as on each of its subscales (p < 0.0001). Acute measures of ‘mystical experience’, ‘emotional breakthrough’, and ‘communitas’ correlated positively with post-psychedelic changes in connectedness (r = 0.42,r = 0.38,r = 0.42, respectively,p < 0.0001). In the RCT, psilocybin therapy was associated with greater increases in WCS scores compared with the escitalopram arm (ηp2 = 0.133, p = 0.009).
Conclusions
The WCS is a new 3-dimensional index of felt connectedness that may sensitively measure therapeutically relevant psychological changes post-psychedelic use. We believe that the operational definition of connectedness captured by the WCS may have broad relevance in mental health research.
Papers cited by this study that are also in Blossom
Agin-Liebes, G. I., Ekman, E., Anderson, B. T. et al. · Journal of Humanistic Psychology (2021)
Rodríguez Arce, J. M., Winkelman, M. J. · Frontiers in Psychology (2021)
Argento, E., Capler, R., Thomas, G. et al. · Drug and Alcohol Review (2019)
Belser, A. B., Agin-Liebes, G. I., Swift, T. C. et al. · Journal of Humanistic Psychology (2017)
The data used in the psychometric validation procedure were obtained from two prospective, observational online surveys, the Global Psychedelic Survey (GPS) and the Ceremony Study (CS), investigating psychedelic use in real-world settings and in ceremony or retreat settings, more specifically in case of the latter. Both studies were approved by the Imperial College Research Ethics Committee and the Joint Research Compliance Office at Imperial College. Five other papers on different topics were published using data from these same studies.
The survey studies collected data about self-selected individuals' psychedelic experiences using an observational prospective cohort design. Individuals could participate in either study if they were at least 18 years old, had a good comprehension of the English language and if they intended to take a classic psychedelic within 2 months. Participants who planned to take a psychedelic via their own initiative (GPS) or within a planned ceremony or retreat setting (CS) could sign up online via the platform www. psych edeli csurv ey. com. After giving informed consent, participants received email reminders including links to the surveys at different time points before and after the indicated date of the experience. The surveys were completed online on the platform Survey-Gizmo. All obtained data were anonymous, and no personally identifying information was collected apart from e-mail addresses-which we required for participants to be sent the survey links. No data that could identify individuals or their responses have been shared, and no IP addresses were collected.
Only measures relevant to the current analyses are reported here. In both studies, a baseline survey was completed 2 weeks prior to the scheduled experience. This included demographic information, psychological trait variables related to connectedness and the 23-item WCS (see below). In case of the ceremony study, a second time point was then completed by participants the day after the psychedelic session to assess, retrospectively, acute subjective experiences linked to the psychedelic. The WCS was repeated at three endpoints to assess sensitivity to change and postdictive validity: 2 weeks, 4 weeks, and again 6 months following psychedelic use. Data from a pooled sample of 1293 participants were analysed: 886 from the Ceremony Study and 407 from the Global Psychedelic Survey.
Items of the Watts Connectedness Scale (WCS) were inspired by the results of a thematic analysis of 6-month follow-up interviewsBased on these qualitative findings, twenty-three items were chosen pertaining to connectedness, which we hypothesised would cluster into 3 dimensions, namely, connectedness to self, connectedness to others and connectedness to the wider world and spirituality. Five experts (academic and clinical professionals with psychology backgrounds, working in psychedelic research) assessed the items and revised them if needed (R Watts, L Roseman, M Kaelen, M Nour, and R Carhart-Harris). Items were rated on a 0-100 visual analogue scale (VAS), where 0 corresponded to 'not at all' and 100 to 'entirely'. The instruction for the scale reads as follows: 'Reflecting on how you have felt over the past 2 weeks, please rate the following items on a scale from "Not at all" to "Entirely" according to how you have felt over this time period. Please answer every item, even if you are unsure or feel the item is unclear or poorly worded. Drag the indicator to a position on the scale that shows how much you agree or disagree with each of the following statements'.
The Social Connectedness Scale (SCS)consists of 8 items measuring belongingness, on a 6-point Likert scale.
The NR-6) is a short-form version of the Nature Relatedness Scale (NR) that measures connection with nature on a 5-point Likert scale.
The Brief Experiential Avoidance Questionnaire (B-EAQ)) contains 15 items that measure behavioural avoidance, distress aversion, procrastination, distraction/suppression, repression/denial and distress endurance, on a 6-point Likert scale. Flourishing Flourishing was measured using Flourishing Scale, which assesses perceived success and competence in areas spanning relationships, self-esteem, meaning and purpose in life through eight item rated on a 7-point Likert scale. Wellbeing The 14-item Warwick-Edinburgh Mental Wellbeing Scale (WEMWBS)) was included to measure psychological wellbeing. Responses were rated on a 5-point Likert scale.
The Spielberger State-Trait Anxiety Inventory's Short-Form Trait Version (STAI-SF)) is a 6-item scale scored on a 4-point Likert scale.
Few measures were used to assess the acute psychedelic experience. These were administered retrospectively, 1 day after the experience. The measures represent the acute experience of connection on the three dimensions and hence are potential mediators for long-term changes.
The Emotional Breakthrough Inventory (EBI)) assesses moments of emotional breakthrough, catharsis or release. It is a 6-item scale scored on 0 to 100 visual analogue scale (VAS).
The Mystical Experience Questionnaire (MEQ)) is a 30-item scale scored on a 5-point Likert scale. It consists of four factors which measure different dimensions of the mystical-type experience: 'mystical', 'positive-mood', 'transcendence of time and space' and 'ineffability'.
The Communitas Scale (COMS)) assesses moments of being in harmony with the group and feeling a sense of belonging and connection to the group. It is an 8-item scale scored on a 7-point Likert scale.
Exploratory and confirmatory factor analyses (EFA and CFA, respectively) were performed to determine and test the factor structure of the WCS. The GPS sample (N = 407) was used for EFA, the larger CS sample (N = 819) for CFA.
As a first step, the number of factors to be extracted was identified through a combination of several heuristics, including visual examination of the scree plot, the 'Kaiser rule', which accepts as reliable factors, those whose corresponding eigenvalue is larger than one, optimal coordinate, parallel analysis and acceleration factor tests). Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy and Bartlett's test of sphericity were used to test the sample adequacy for EFA. Maximum likelihood estimation was chosen to allow for continuity with CFA results. The selected rotation was oblimin, as this rotation method favours interpretability and allows factors to intercorrelate. The subscales were based on the factors extracted and interpreted through investigation of covariance-based factor loading patterns. To maximise clarity and simplicity in interpretation, two guiding criteria were considered. Each item assigned to a subscale should demonstrate a minimum factor loading of at least 0.3and maximum cross loading on any other factor should be 0.2.
Based on the factor structure determined through EFA, three first-order latent variables were included, as well as an additional second order latent variable (WCS total) that was aimed to capture correlations between the first-order subscales, which were all set to load onto this second-order variable. To account for potential method effects, the error terms between negatively worded items were allowed to correlate. Metrics of each latent variable were determined by fixing the loading of the first item to 1.0 for each factor. Acceptable model fit was determined through a combination of fit indices, including the comparative fit index (CFI > 0.9), standardised root mean square residual (SRMR < 0.08) and root mean square error of approximation (RMSEA < 0.08). Coefficient Cronbach's alpha was used to assess internal consistency of the latent variables, with > 0.8 and > 0.9 representing high and excellent reliability, respectively. Additionally, composite reliability was calculated. It is less prone to over-or underestimations of reliability at a population level than Cronbach's alpha, with a threshold of 0.7 suggesting acceptable consistency.
The construct validity of the WCS was evaluated by inspecting how total and subscale WCS scores related to other previously validated measures. Pearson's correlations were calculated between WCS components and other relevant measures taken at baseline within the ceremony study sample (N in analysis = 819), including the B-EAQ, SCS, NR-6, FS, WEMWBS and STAI-SF. Resulting correlations were interpreted based on effect sizes: negligible (up to -0.1; 0.1), low (between -0.1 and -0.3; between 0.1 and 0.3), moderate (between -0.5 and 0.3; between 0.3 and 0,5), and high (from -0.5; 0.5).
In order to test whether the psychedelic experience influenced WCS scores in the Ceremony Study data, linear mixed models (LMM) were fitted to assess longitudinal changes in WCS and its subscales. The LMM used restricted maximum likelihood estimation and included in each case the WCS (subscale) score as dependent variable, time as a fixed factor and a random intercept to account for individual differences between participants. Eta squared effect sizes are reported for each model, where values of 0.02, 0.13 and 0.26 were considered to be small, medium and large, respectively). Postdictive validity was then assessed through Pearson correlations between changes on WCS total score between baseline and 2 weeks post-experience and measures of the acute psychedelic experience, including MEQ, EBI and COMS. All statistical analyses were conducted in RStudio (v1.2).
All 23 original WCS items were entered into a maximum likelihood-based exploratory factor analysis (EFA). The global psychedelic survey (GPS) dataset was found to be suitable for factor analysis, as its Kaiser-Meyer-Olkin (KMO) measure of sampling adequacy was 0.92 and Bartlett's test of sphericity was significant (χ2() =188.75, p<0.0001). Although a fourth eigenvalue was found to be above 1 (at 1.007), visual examination of the scree plot (see supplementary Figure), parallel analysis and optimal coordinate estimates of the ideal number of factors to be extracted pointed to a 3-factorial solution, which was chosen for the subsequent extraction of factor loadings. Item loading patterns (supplementary table) revealed that four items had significant cross loading (> 0.2), which were therefore removed and the EFA repeated. These excluded items were'"I have felt connected to deeper aspects of myself', 'I have felt connected to insight intuition', 'I have felt connected to my values', and 'I have felt connected to strangers'. The remaining 19 items all had satisfactory loading patterns, where the first factor explained 22% of the variance, the second factor 16% and the third factor 12%, amounting to a total of 50% of variance explained in the final 3-factorial solution. Based on the content of items that loaded on each factor, definitions were assigned that each represented a subtype of connectedness, in line with the hypothesised 3-factorial structure of connectedness (supplementary table). Accordingly, the first factor was named 'connectedness to world' (CTW), the second factor was named 'connectedness to self' (CTS), and the third factor was named 'connectedness to others' (CTO) The 3-factorial structure consisting of 19 remaining items showed satisfactory psychometric properties in the EFA and then subjected to a subsequent confirmatory factor analysis (CFA) in the separate Ceremony Study dataset (N=819), to which a second-order WCS total score was added onto which the three latent subscales were set to load. The model showed acceptable fit with CFI = 0.902, RMSEA = 0.076 (confidence intervals 0.072-0.081) and SRMR = 0.060. Standardised factor loadings of the resulting model are shown in Figure. Cronbach's alphas for the three first-order latent factors were 0.84, 0.87 and 0.90, while composite reliabilities were 0.79, 0.87 and 0.90, for connectedness to self, others and the world, respectively. The second-order latent variable subsuming all three subscales had a composite reliability of 0.86. From here on, the total score of each of the subscales was calculated by averaging all of the items that belong to this subscale, and the total WCS score was calculated by averaging the three subscales.
Correlation coefficients between the WCS, its subscales and other included measures are displayed in Table. Discriminant validity could be established among the WCS subscales following thecriterion; i.e. the square root of the average variance extracted (AVE) was larger than any inter-construct correlations, although correlations among WCS subscales were generally high, ranging from 0.51 (CTO and CTW) to 0.62 (CTS and CTW). The highest correlations with secondary measures were observed between CTO and wellbeing (WEMWBS, r = 0.82), social connectedness (SCS, r = 0.78) and flourishing (FS, r = 0.72), which were greater than the square root of the AVE, meaning that discriminant validity for this subscale could not be established against the mentioned secondary measures.
Mixed linear models were fitted to test for changes in connectedness across time in the Ceremony Study data. Parameter estimates for each time point and subscale are presented in Table; all values were significantly (p < 0.0001) increased at 2 weeks, 4 weeks and still at 6 months following the psychedelic experience (Fig.), with consistently large effect sizes ranging from η 2 = 0.192 for connectedness to self to η 2 = 0.339 for changes in the overall WCS score. Estimation of individual contrasts showed that for each subscale, 2 weeks, 4 weeks and 6 months time points differed from baseline at p < 0.0001; additionally, the overall WCS score was significantly lower at 6 months, compared with 2 weeks (mean difference = 3.28, se = 1.25, p = 0.027), as was connectedness to others (mean difference = 4.72, se = 1.41, p < 0.01). Postdictive validity was good; and Pearson correlations between changes in WCS total scores from baseline to 2 weeks and measures of the acute psychedelic experience were significant in the case of mystical-type experience (MEQ, r = 0.42, p < 0.0001), emotional breakthrough (EBI, r = 0.38, p < 0.0001) and communitas (COMS, r = 0.42, p < 0.0001) measured retrospectively 1 day following the psychedelic ceremony (Fig.).
The observed factor structure confirmed the three-factorial structure of connectedness, including a connection to self, connection to others and connection to the world. The dimensions of the scale were in line with the hypothesised constructs. The factor loadings showed a simple structure with minimal cross loadings, which promoted a straightforward interpretation of scores, and the internal consistency of the scale was high. Most importantly, in the confirmatory factor analysis, the second-order total WCS score, which is comprised of the three subscales, had a high composite reliability. This result suggests that the three subscales can be converged into one construct which measures a comprehensive spectrum of connectedness. The construct validity of the scale was assessed via comparison with other related scales that measured psychological flexibility, wellbeing, social connectedness, nature relatedness and anxiety. High correlations were observed between total WCS and its subscales and scores on the other measures, showing high convergent validity with these scales. The high convergent validity with a variety of scales implies a broad, multidimensionality to the WCS. Regarding divergent validity, CTS and CTW showed divergence from other measures, while CTO did not diverge from few of the other measures such as SCS and WEMWBS. Overall, we can conclude that the total score of WCS does diverge from other measures, yet there is still a need to investigate divergent validity by comparing WCS with other measures that were not included in the current study (e.g., the relation between CTW and different measures of spirituality). As CTO did not diverge from SCS, it is important to note the relationship between them. The two scales converge in terms of their shared reference to the negative affect that can accompany social disconnection and only slightly differ on the degree to which actual social relationships exist. One minor difference is that SCS features items that assess social connectedness that go beyond one's direct social environment. Total WCS also had high correlations with SCS, which most likely implies that social connectedness is an important aspect of connectedness. This finding follows the principal idea that humans are a species whose survival, thriving and meaning-making depend on good social relations. A recent big data study supported this notion by showing that social connection is the most crucial protective factor in preventing depression. The postdictive validity of WCS was excellent. Previous psychedelic research showed that different psychedelic experiences can predict long-term changes, in naturalistic studies) and clinical studies. Measures that were used in previous psychedelic research (MEQ, EBI and COMS) predicted in the current study long-term changes in WCS. This means that the emotional, social and spiritual components of the acute psychedelic experience impact the sense of connectedness for a prolonged period after the psychedelic has been metabolised. This result adds to a large body of findings showing that acute subjective effects induced by psychedelics are fundamental to the therapeutic efficacy induced by psychedelics.
The inclusion criterion for the RCT was major depressive disorder (MDD) of a moderate to severe degree, diagnosed by a doctor, and with the participant scoring 17 + on the 21-item Hamilton Depression Rating scale [HAM-D])-as assessed by a study psychiatrist at the point of telephone screening. Exclusion criteria were current or previously diagnosed psychotic disorder; immediate family member with a diagnosed psychotic disorder; medically significant condition rendering unsuitability for the study; history of serious suicide attempts (requiring hospitalisation); history of mania; blood or needle phobia; positive pregnancy test at screening or during the study; and current drug or alcohol dependence; and any diagnosed or suspected psychiatric comorbidities felt to jeopardise the formation of a good therapeutic relationship. Information about the study's recruitment was sent to general practitioners via the North West London Clinical Research Network. However, patients were also allowed to self-refer to the study if they were UK residents. Patients who initiated contact with the research team (via email, letter or telephone) were sent a study information sheet, a subsequent telephone screening and further face-to-face medical and psychological screening including liaison with all participants' healthcare providers.
This was a phase 2 double-blind randomised controlled trial. Participants were randomly assigned 1:1 to either a psilocybin condition or an escitalopram condition. Participants in both groups received the same therapeutic intervention which focused on enabling participants to accept and allow any difficult feelings, connect to any insights and engage with their embodied 'felt sense' throughout the therapy process. This approach is described in detail in the ACE (Accept, Connect, Embody) model manual). The primary outcome measure was the change in self-rated scores on the Quick Inventory of Depressive Symptomatology (QIDS-16) from baseline to the primary endpoint. The primary endpoint was 6 weeks after the first psilocybin session and 3 weeks after the second psilocybin session (also the day of the final dose of 6 weeks of daily escitalopram). Secondary measures included the Hamilton Depression Rating Scale (HAM-D) and Montgomery-Asberg Depression Rating Scale (MADRS) clinical interviews to assess depression symptoms, the Beck Depression Inventory (BDI) self-rated measure of depressive symptom severity and other self-rated scales including the WCS. Secondary measures were administered at baseline and 6-week endpoint. The psilocybin condition (n = 30) comprised two 4-6-h sessions in which participants consumed 25-mg psilocybin whilst listening to a therapeutic music playlist, under the guidance of two therapists who were allocated to them for the entirety of the trial. These sessions were 3 weeks apart. Participants in the psilocybin condition also took daily capsules, containing placebo, from the day after the first guided dosing session until the 6-week endpoint. The escitalopram condition (n = 29) comprised two 4-6-h sessions in which participants consumed a very small dose of psilocybin (1 mg) whilst listening to the same therapeutic music playlist, under the guidance of their two allocated therapists. These sessions were also 3 weeks apart. Participants in the escitalopram condition took daily capsules, containing the antidepressant medication escitalopram, from the day after the first guided dosing session until the 6-week endpoint. Participants in both groups received nine non-drug therapeutic sessions with their two allocated therapists which took place from 2 weeks before the first psilocybin session until the 6-week endpoint. A minority of the non-drug therapeutic sessions (which were termed 'preparation' and 'integration' sessions) took place with just one therapist via tele-health, but most included both therapists and took place face-toface in a psilocybin therapy room. Both therapists were present during the entirety of both guided dosing sessions, for both conditions. The final non-drug therapeutic session at the 6-week endpoint was followed by a research interview in which participants completed primary and secondary outcome measures. It is important to note that participants in the escitalopram condition received the nine non-drug therapeutic sessions under the guidance of one or both of their two allocated therapist 'guides', and two 4-6-h guided psilocybin sessions with both therapist guides. Therefore, participants in both conditions received a large amount of psychotherapeutic support and personal attention.
The Quick Inventory of Depressive Symptomatology (QIDS) was the primary outcome of the RCT (Carhart-Harris et al. 2021), and is used in the current paper to define responders and non-responders to both psilocybin and escitalopram. Response was defined as more than 50% reduction in QIDS.
In the original 23-item version of the WCS was included in the trial, but for the purpose of this validation paper, we used only the 19 items that load well onto the aforementioned 3 dimensions of connectedness i.e. the subscales CTS, CTO and CTW.
Groups were split into responders and non-responders based on more than 50% reduction in baseline depression scores. Mixed repeated measures ANOVA (2 × 2 × 2 betweenwithin) was used to measure whether WCS differed between psilocybin and escitalopram (hypothesis H4), and whether this was dependent on response rates (hypothesis H5). A significant triple interaction would suggest that psilocybin and escitalopram differ in their therapeutic mechanism and that this difference is related to connectedness. WCS scores were included as dependent variable, time as within-subject effect with 2 levels (baseline and 6 weeks) and condition and response as between-subject independent variables with 2 levels each (psilocybin vs. escitalopram; and responders vs. non-responders). The resulting three-way interaction was time X condition X response. Multiple pairwise comparisons were calculated to test simple main effects: within-group comparisons (from baseline to 6 weeks) at each level of the group factor (psilocybin vs. escitalopram) and betweengroup comparisons at each time-point (baseline and week 6) were calculated. To test that connectedness is part of the mechanism of action in psilocybin but not escitalopram, it was possible to use moderated mediation analysis. However, we decided not to do so, as WCS and QIDS were measured in the same time point (6 weeks), and accurate mediation analysis require that the mediating variable is tested before the outcome. All statistical analyses were conducted in RStudio (v1.2).
Four subjects in the escitalopram group came off the medication before the end of the trial and were excluded from the analysis. From the psilocybin group, one subject was excluded due to smoking cannabis on a regular basis during the trial period, and two were excluded for not having the second psilocybin dosing day due to COVID-19 lockdown restrictions. After exclusion, the escitalopram group consisted of 25 subjects and the psilocybin group, 27 subjects. Based on changes in QIDS scores, 13 subjects were defined as responders in the escitalopram group (52% of the total escitalopram group), and 20 in the psilocybin group (74% of the total psilocybin group). The mixed (2 × 2 × 2 between-within) rm ANOVA revealed a significant main effect of time (baseline vs 6 weeks) [F(1, 48) = 51.36, p < 0.0001, η p 2 = 0.517]; significant interaction effect for time and condition (escitalopram vs. psilocybin), aligned with hypothesis H4 [F(1, 48) = 7.39, p = 0.009, η p 2 = 0.133] (see Fig.); significant interaction effect for time and response (non-responders vs. responders) [F(1, 48) = 28.73, p < 0.001 , η p 2 = 0.374]; and significant triple interaction for time, condition and response, aligned with hypothesis H5 [F(1, 48) = 9.62, p = 0.003, η p 2 = 0.167]. Two-sample t-tests were used to test whether WCS scores were different at baseline and at 6 weeks. No significant differences were observed at baseline for condition (mean difference = 1.8, Hedge's g = 0.14, p = 0.614) and response (mean difference = 3.73, Hedge's g = 0.29, p = 0.311), suggesting that the interaction effects were not driven by difference at baseline. Significant differences in ΔWCS scores were observed for condition (mean difference = 19.8, Hedge's g = 1.07, p < 0.001, higher for psilocybin) and response (mean difference = 24.9, Hedge's g = 1.45, p < 0.001, higher for responders). Paired samples t-tests were used to compare WCS at baseline vs. 6-week follow-up. There were no significant difference for both escitalopram non-responders (mean difference = 4.6, Hedge's g = 0.42, p = 0.158, n = 12) and psilocybin non-responders (mean difference = 2.99, Hedge's g = 2.5, p = 0.512, n = 7). There were significant differences for both escitalopram responders (mean difference = 14.3, Hedge's g = 0.95, p = 0.004, n = 13) and psilocybin responders (mean difference = 38.58, Hedge's g = 2.29, p < 0.001, n = 20). To test whether the change in WCS scores for psilocybin responders was higher than for escitalopram responders, as hypothesised, a two-sample t-test was used to compare the change in WCS scores. Aligned with hypothesis H5, ΔWCS was significantly greater for psilocybin responders compared with escitalopram responders (mean difference = 24.5, Hedge's g = 1.52, p < 0.001), but not greater for psilocybin non-responders compared to escitalopram non-responders (mean difference = 1.6, Hedge's g = 0.14, p = 0.76). Overall, results were consistent with our prior hypotheses, showing that changes in WCS were larger for psilocybin vs escitalopram and larger for psilocybin responders vs escitalopram responders (see Fig.). The significant triple interaction suggests that while both psilocybin and escitalopram can alleviate depression, psilocybin leads to stronger increases in connectedness even when comparing clinical responders from both groups. This suggests that the mechanism of action by which psilocybin and escitalopram improve depression is different and that this difference is related to connectedness which is higher for psilocybin. Further descriptive analysis of the three dimensions was conducted. For escitalopram non-responders, CTS and CTO did not show significant changes (CTS, Hedge's g = -0.064, p = 0.823; CTO, Hedge's g = 0.37, p = 0.21), while CTW did show significant increase (Hedge's g = 0.73, p = 0.023). For escitalopram responders, CTS did not show significant changes (Hedge's g = 0.27, p = 0.34), while CTO and CTW did show significant increases (CTO, Hedge's g = 1.46, p < 0.001; CTW, Hedge's g = 0.79, p = 0.012). For psilocybin non-responders, none of the dimensions showed significant changes (CTS, Hedge's g = -0.237, p = 0.476; CTO, Hedge's g = 0.11, p = 0.739; CTW, Hedge's g = 0.56, p = 0.113). For psilocybin responders, all of the dimensions showed significant increases (CTS, Hedge's g = 1.85, p < 0.0001; CTO, Hedge's g = 1.45, p < 0.0001; CTW, Hedge's g = 1.4, p < 0.0001).
The result of our analyses support the validation of the WCS as an instrument to measure connectedness as a construct comprising three categories (connectedness to self, others, world). Aligned with our primary hypothesis, the validation of the scale has shown that those three categories can be grouped together into one single factor to measure a generalised type of connectedness. The WCS, and all of its subscales, showed significant increase up to 6 months after a psychedelic experience in three independent studies. Importantly, three different elements of the acute psychedelic experience-emotional, spiritual and social-predicted the long-term changes in WCS. Finally, in a double-blind randomised controlled trial comparing psilocybin-assisted therapy with escitalopram-assisted therapy for depression, the WCS showed robust post-treatment changes with psilocybin-assisted therapy that were significantly larger than for escitalopram-assisted therapy, even when comparing just the responders from both groups. These results confirm the hypothesis that was developed in the exploratory qualitative research which kindled the current quantitative investigation, which proposed that the therapeutic mechanism of psychedelic-assisted therapy is different to conventional antidepressants, with an increased sense of connectedness to self, others and the world being specific to psychedelic therapy.
Many constructs which were originally conceptualised to be related to one particular aspect of connectedness (i.e. experiential avoidance to CTS, social connectedness to CTO, nature connectedness to CTW) were found to correlate with the total score of WCS. This supports the suggestion of a more general connectedness at the root of the various specific types of connectedness that have been previously studied. Based on the findings of this study, we now predict, for example, that an individual reporting feeling connected to a sense of meaning and purpose as well as their body and emotions would also report feeling connected to other people; or that someone describing feeling connected to nature would also report feeling connected to humanity at large and their own emotions. There will of course be exceptions to this, with a whole range of unique profiles of connectedness, but overall high scores on one domain (self/others/world) suggest high scores on others, just as low scores in one aspect suggest a disconnection across multiple domains. Extending on this theme, we hypothesise that high multidimensional connectedness may be a protective factor for mental health and wellbeing. The construct of 'connectedness' has developed over time to have different meanings and different applications. Many older conceptualisations described connectedness as some form of interpersonal relatedness, some emphasised the self-in-relation-to-others context-dependent nature of connectedness, whereas others have favoured more internally focused experiential and emotion-oriented interpretations. Other types of connectedness have also been discussed in older literature, but have remained relatively underexplored.is a notable exception, conceptualising connectedness with three subtypes of connectedness (self, others and a larger purpose in life) which maps closely onto the model presented here. It is our hope that the WCS is able to capture both the core essence and multidimensional nature of the phenomenon of connectedness, and we hope that future use of this scale will help to revive an interest in the science of connectedness and its relevance to health.
Psychedelic therapy tends to be experienced in a more embodied way than traditional talking therapy. During a 5-6-h psilocybin session, participants are encouraged to be with their felt sense in the body and refrain from speaking very much until afterwards, in order to more fully connect with somatic and emotional aspects of experience, rather than getting distracted by cognition or communication. Participants engaging in psychedelic therapy tend to describe feeling connected to deeper aspects of themselves than they usually feel, and being able to 'sit with' more intense and often uncomfortable emotions than they can usually access or tolerate. Therefore, 'selfconnectedness' in psychedelic therapy tends to be described as connectedness to the senses, the body, and emotions. Previous conceptualisations of 'self-connection' have been largely cognitive, emotional and behaviouraland have not included embodied/somatic aspects. CTS, as formulated by the WCS, acknowledges embodied qualities of 'the self', e.g., with the inclusion of the specific items 'I have felt connected to my body' and 'I have felt connected to my senses'. The original 23-item version of the WCS, CTS contained a number of items that map on to Klussman et al.' s conceptualisation of CTS (values, insight, self compassion) but were removed because they were found to cross load with CTW: 'I have felt connected to deeper aspects of myself','I have felt connected to insight/intuition' and 'I have felt connected to my values'. A further item,'I have felt connected to a purpose in life', was hypothesised to load into the CTS subscale until factor analysis placed it in CTW. By removing these four items from the subscale, CTS becomes a more visceral, emotional and embodied connection to self. Of all CTS items in the original scale, the items with the highest factor loadings for CTS were those relating to emotions (i.e. the highest loading was for "I have felt connected to a range of emotions). This could be viewed as reflective of a differential 'willingness to feel' in the CTS subscale, as well as the core affective and interoceptive quality of CTS, as defined by this subscale's six items.
CTO maps closely on to the well-researched concept of social connectedness, which has been described byas being related to one's view of the self in relation to others or as a 'cognitive structure representing regularities in patterns of interpersonal relatedness'. One model of social connectedness is derived from a factor analysis of the UCLA Loneliness Scale (UCLA LS-R). Loneliness has been defined as the inverse of human (social) connectedness. The UCLA LS-R has a three factor model: isolation, relational connectedness and collective connectedness. Relational connectedness refers to actual social networks, whereas isolation refers to an individual's mental representations of how socially connected or disconnected they are. The WCS includes all three factors of the UCLA LS-R: the CTO subscale covers isolation and relational connectedness and collective connectedness is included in CTW. In a recent large-scale population survey study in the UK, social connection was found to be the strongest protective factor against depression). The quality and quantity of individuals' social relationships have been linked not only to mental health but also to both morbidity and mortality; a large meta-analysis found that social relationships are more effective at helping people to live long lives than any other factor, including hypertensive treatment. Human social genomics has begun to analyse how loneliness affects our immune system and causes chronic inflammation as a precursor to disease (Cole 2014). Combining community development with healthcare has been found to dramatically reduce emergency hospital admissions in a project in the UK where a town was shaped into a 'compassionate community' via various interventions whereby people of the town were given the means to connect with each other.
CTW items represent a state of 'transpersonal' ego-transcendence which may be a vital aspect of the therapeutic process catalysed by psychedelics) and other practices. The CTW subscale relates to 'self-transcendence', defined as the capacity to transcend self-boundaries. The expansion of self-boundaries can occur at the interpersonal (opening up one's sense of self to include other beings) and transpersonal (connecting with nature and a spiritual principle) levels. All items in the CTW subscale relate to connecting with the world beyond each individual, which is captured also by the item 'I have felt connected to a purpose in life'. This item was originally hypothesised to belong to the CTS subscale but analyses found it to load onto CTW, suggesting that 'purpose' is not related to the good of the individual, but to the good of the world. CTW contains one item relating to nature connectedness, and one item relating to interconnectedness of everything. Both of these items represent a kind of self-transcendence commonly reported by people after psychedelic experiences, whereby one feels part of an interconnected web of life, and recognises one's place in the patterns and fabric of the natural world. This sense of inter-relatedness is a fundamental aspect of indigenous worldviews from all over the globe. Many indigenous belief systems share a view of people and nature as part of an extended ecological family: for example, the Māori, indigenous people of Aotearoa; the Shipibo of Peru; the Raramuri of Chihuahua, Mexico; and the Skokomish of Washington; the Druids of Wales. These different groups, and many more, separated by geography, culture and time, have described this phenomenon. The Māori worldview (te ao Māori) acknowledges the interconnectedness of all living and non-living things. The Raramuri worldview includes 'Iwigara': the total interconnectedness of all life, physical and spiritual. From the point of view of these belief systems, feeling separate from nature would signify a state of disconnectedness and constitute a significant rupture in wellbeing. Connectedness to ourselves as part of an inter-related web of life may be essential to the survival of our species, and this appears to be a common insight occurring during psychedelic therapy, as many quotes from participants in psychedelic research studies attest. Such insights are often reported to lead to pro-environmental behaviours. If scientific study of connectedness should find that the feeling of being interconnected with nature is associated with wellbeing and pro-environmental behaviour, it will be important to recognise the original, longstanding provenance of this knowledge and include indigenous perspectives in the study of connectedness. For example, the University of Auckland is including the WCS in a study of connectedness and existential distress in Māori and non-Māori people with a life-limiting illness. The project is designed and led by Māori colleagues, who have added two additional CTW items, which reflect Te ao Māori, to supplement the 19-item WCS: 'I have felt connected to toku whakapapa, my family ancestry' and 'I have felt connected to toku whenua, my land'. The dual meaning of 'whenua'exemplifies Māori wairua (spirituality), whereby interconnectedness with everything is both grounded and sacred. The WCS also contains items relating to connecting to a source of universal love and connecting to a spiritual principle, themes which are common in psychedelic therapy, and which again map onto indigenous spiritualities, which can be differentiated from religion and are based on a sense of connectedness and respect for the 'earth, ancestors, family and peaceful existence') 'an internal connection to the universe' (Department of Economic and Social Affairs, UN 2009) or an 'intrinsic, autonomous, and subjective sense of connection with a sacred dimension of reality, which provides meaning, purpose, connection and balance'. The inclusion of spiritual items within the WCS may be considered by some to be antithetical to scientific enquiry. However, as many of the participants in our previous qualitative research) who indicated spiritual connectedness had been previously non-spiritual, this change in metaphysical beliefs seems like an integral aspect of the psychedelic experience. The importance of mystical-type experience as a predictor of positive outcomesrequires us to investigate further the relationship between connectedness and spirituality, which the CTW items may facilitate.
Psilocybin showed (statistically significantly) larger change on the WCS than escitalopram. Importantly, the larger change was also statistically significant when looking only at the responders of both groups based on change in depression scores. A triple interaction effect was found between condition (psilocybin vs escitalopram), response (responders vs non-responders) and time (before therapy vs 6-week followup). This triple interaction effect supports the hypothesis that the therapeutic mechanism of psilocybin is different from that of escitalopram's. While both are effective in reducing depression, the clinical response in the psilocybin group was strongly associated with increased connectedness, and less so in the escitalopram group. That there were still increases in WCS scores seen in the escitalopram responders group does not match qualitative reports from patients indicating that SSRI antidepressants can actually lessen a sense of (emotional) connectedness, by making them feel emotionally numbed. The increases in WCS scores in the escitalopram responders group may be linked to the following: (1) improvements in other domains of connectedness than CTS, as data shows; (2) the extensive personalised care, attention and therapeutic support that participants in both treatment arms of this trial received. In common healthcare practice (in the UK, at least), SSRI medications are administered without extensive psychotherapeutic care; and (3) some non-orthogonality between depression and connectedness. Psychedelic-assisted therapy is currently applied to different conditions such as depression, anxiety, addiction, anorexia, obesity, chronic pain, OCD and PTSD. In case such transdiagnostic application will prove to be effective, a search for an underlying mechanism will become relevant. Alienation, 'dislocation' and disconnection have been hypothesised to underlie many mental health conditions, supporting the idea that disconnectedness is a transdiagnostic phenomenon: these include eating disorders, borderline personality disorder, PTSD, depression, addiction, anxietyand ADHD (van den Berg and van den Berg 2011). It might be that traumatic experiences in relationships with caregivers, others and society can damage our access to a sense of connectedness and that psychedelic (and other) profound experiences can enable sudden access to that state. This resonates with the reports of people who have had meaningful psychedelic experiences. To test whether and confirm that the phenomenon of a foundational multidimensional connectedness has validity and clinical utility, it will need to be measured in a range of different clinical populations pre and post 'treatment'. Future observational and experimental research studies in various settings looking at many different populations are including the WCS in their battery of measures. The CIPPRes Clinic (Central North West London-Imperial Psychopharmacology & Psychedelic Research Clinic) will measure changes in WCS scores for different clinical presentations (i.e. anorexia nervosa, chronic pain, depression, anxiety). This transdiagnostic research avenue will be important for a 'psychedelicisation' of medicine, because a successful integrationand not assimilation-of psychedelics into psychiatry may require a change in the way mental and emotional suffering is understood by the dominant paradigms. Alongside transdiagnostic clinical research, psychedelic sessions in group contexts will be a crucial avenue for study, because of the additional boost to connectedness that is experienced in such settings). In the current study, emotional, social and spiritual qualities of the psychedelic experience predicted the changes in connectedness. Psychedelic therapy is intensely context dependent (Hartogsohn 2020)-and thus, the extent to which a participant is able to experience emotional, social and spiritual insights will itself rest on how they are therapeutically prepared for the psychedelic experience, supported during it, and after it. The 'integration' phase post dosing is considered essential for acute experiences of connectedness to be consolidated and incorporated into daily life. Integration sessions, where psychedelic therapy has been effective, typically focus more on a person's wishes for making changes to how they behave within their community and ecosystem than on biomedical issues like changes to their symptoms of depression. Considering connectedness (or its absence) as a transdiagnostically foundational factor is a reminder that-while connectedness can be temporarily boosted by psychedelic therapy-ongoing psychological, communal, political, ecological and spiritual work is needed to maintain connectedness. We believe that the multiple dimensions of connectedness must be addressed by modern models of psychedelic-assisted therapy in order for its safety and efficacy to be optimised. In this way, psychedelics may assist in shifting the dominant biomedical mental health model into a 'biopsychosocial' model, or even a 'bio-psycho-social-environmental-spiritual' model, where mental and emotional suffering is not considered as simply a function of individual pathology, but linked to much broader social, environmental and spiritual factors. Interestingly, this model of health maps onto the Shipibo conception of health as encompassing connectedness to self, community and the world) and the already well-established model of Māori health, Te Whare Tapa Wha), which comprises spiritual, mental, physical and family connectedness.
One of the biggest challenges facing psychedelic therapy is how to help participants hold on to the benefits which are often lost after a few months. If multidimensional connectedness is one of the main benefits, then being able to study it easily will enable researchers to study different ways of maintaining it after sessions. Without this kind of 'integration work', there is a risk that people will become dependent on frequent psychedelic experiences in order to feel connected, rather than developing other practices and contextual changes. It is hoped that the WCS will enable future quantitative measurement of how connectedness typically wanes over time, which may inform the development of therapy protocols with guidance around when repeat sessions could occur. Also, integration approaches for maintaining connectedness, such as community and ecotherapy interventions, can be evaluated and compared. The WCS may also help identify some of the risks of psychedelic therapy and could offer particular usefulness in helping us learn more about some commonly experienced difficulties in the much understudied integration phase (post-psychedelic therapy), as clinical trials only collect data for a few months after the session. Sometimes, the integration period can be a time of confusion and overwhelm. Therapists working with people who have had psychedelic sessions and need further support (integration therapists) tend to advise staying present in the body, senses and emotions in the weeks after a psychedelic session. Embodied self-awareness and connection to a supportive and understanding community are both essential to psychedelic integration, in order to 'ground' a profound and potentially destabilising connection to new ideas. Whereas connection to world can be thought of as the branches of a tree reaching up to the sky, connection to self can be considered the trunk of the tree, and connection to others the root system. Thus, 'over-connecting' to the world (CTW) without a solid foundation of connection to self (CTS) could indicate the need for psychotherapeutic integration and grounding, rather than further psychedelic sessions. Some examples of over-connecting to CTW without a strong CTS could be an 'ontological shock'-whereby assumptions about what it is to be a conscious living being on earth are deeply challenged-which can sometimes precipitate hypo-manic or manic reactions, 'spiritual bypassing' (Masters 2010) and 'spiritual narcissism'. Another risk of the integration period of psychedelic therapy is the experience of intense disappointment. For individuals who have felt disconnected for much of their life, a sudden burst of connectedness that lasts for a few months but then dwindles may be a risk factor in self-harm or suicide. Therefore, measuring an individuals' connectedness to self, others and the world in the months after a psychedelic session may be important for safety,
The current validation of WCS has a number of limitations: (1) The validation of the WCS is limited by a self-selection bias for the online questionnaire, and potentially also the RCT-e.g., where the majority of volunteers were psilocybin therapy preferring (vs. the SSRI treatment). Pop culture surrounding psychedelics tends to feature elements of connectedness and it is possible that survey and RCT participants were familiar with related topics and how psychedelics may enhance them. Study participants were predominantly WEIRD (white, educated, industrialised, rich, democratic)) reflecting a pervasive problem in psychedelic research. Future studies should test the scale in the wider population. (2) Many participants dropped of the survey study, which could have created attrition bias effects; e.g., those who did not benefit from their psychedelic experience may have been more likely to discontinue. Future studies should take measures to solve such problems, possibly by introducing more incentives for completion of the study. (5) The item creation process for the WCS was based on qualitative reports from a depression study and may therefore be biased by this sample-and by the qualitative nature of that original analysis. In order to assess whether the final validated measure was considered an accurate and appropriate tool by those who had themselves experienced a psychedelicassisted therapy-induced connectedness, the WCS was submitted to the Psychedelic Participant Advisory Network, (PsyPAN) who were asked to review it and consider whether there were any aspects of psychedelic therapy-induced connectedness that were not represented by the measure, or any existent items which they thought did not belong there or were disagreed with. PsyPAN's feedback was that the measure could have asked about connecting to personal values as part of 'connectedness to world', for example, becoming vegetarian, changing to a more meaningful job or joining activist networks. An item relating to 'connectedness to values' was in fact in the original 23-item WCS in the CTS scale but removed after factor analysis because it loaded onto both connectedness to self and connectedness to world. Two other items were removed for the same reason: 'I have felt connected to deeper aspects of myself' and 'I have felt connected to insight/intuition'. These three items taken together point perhaps to a type of self-connectedness which has not been included in the final WCS, which could be conceptualized as less changeable than embodied, sensory and emotional experience, which tends to be transitory. A 'deeper' more immutable aspect of self may need to be re-introduced to measures of connectedness, despite its crossloading here on both CTS and CTW. This crossloading in itself is worthy of future study. (6) The 19-item measure is not exhaustive. There will be aspects of connectedness that are not included in the current WCS. This 19-item measure is a starting point. It is hoped that others will suggest items that are relevant based on their observations. It would be possible to have different versions of this scale validated for different populations, perhaps with the 'W' removed and replaced with a more appropriate letter for that context. Until that time, we hope the current validated WCS will be a starting point for the quantitative study of the state of feeling connected to self, others and the world.
Previous findings that many different dimensions of connectedness are linked to positive mental health outcomes suggest that connectedness, in all its forms, should be carefully explored and defined. The present work supports the view that a fundamental multidimensional state of connectedness exists and has developed a scale that defines and measures this phenomenon. Previously, research findings regarding connectedness have tended to probe only sub-dimensions of the phenomena, making it difficult to compare results and build the research corpus. Having a single measure comprising multiple dimensions of connectedness may help to consolidate the view that these sub-dimensions are inter-related and underpinned by a common generalised connectedness. If used widely, the WCS may help us understand how different aspects of connectedness relate to each other and the interventions and conditions under which connectedness is experienced and maintained. Psychedelic-assisted therapy may prove to be one of the most effective interventions for increasing connectedness among individuals and groups of peopleand future research may reveal how important this effect is for improving and maintaining mental health.
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