Psilocybin therapy for mood dysfunction in... — Research Summary & Context

Psilocybin therapy for mood dysfunction in... — Research Summary & Context | Blossom

Abstract

Mood dysfunction is highly prevalent in Parkinson’s disease (PD), a main predictor of functional decline, and difficult to treat—novel interventions are critically needed. Psilocybin shows early promise for treating depression and anxiety, but its potential in PD is unknown, as safety concerns have excluded people with neurodegenerative disease from previous trials. In this open-label pilot (NCT04932434), we examined the feasibility of psilocybin therapy among people with mild to moderate stage PD plus depression and/or anxiety. 12 participants (mean age 63.2 ± 8.2 years, 5 women) received psilocybin (one 10 mg followed by one 25 mg dose) with psychotherapy. There were no serious adverse events, no medical interventions required to manage effects of psilocybin, and no exacerbation of psychosis. Ten participants experienced treatment-emergent adverse events; the most frequent were anxiety, nausea, and increased blood pressure. We observed no worsening of PD symptomology measured by the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS). On the contrary, non-motor (MDS-UPDRS Part I: –13.8 ± 1.3, p < 0.001, Hedges’ g = 3.0) and motor symptoms (Part II: –7.5 ± 0.9, p < 0.001, g = 1.2; Part III: –4.6 ± 1.3, p = 0.001; g = 0.3) as well as performance in select cognitive domains (Paired Associates Learning [-0.44 ± 0.14, p = .003, g = 0.4], Spatial Working Memory [–0.52 ± 0.17, p = 0.003, g = 0.7], and Probabilistic Reversal Learning [2.9 ± 0.9, p = 0.003, g = 1.3]) improved post-treatment, and improvements were sustained until the final safety assessment one month following drug exposure. Baseline Montgomery-Asberg Depression Rating Scale (MADRS) and Hamilton Anxiety Rating Scale (HAM-A) scores were 21.0 ± 8.7 and 17.0 ± 3.7, respectively. Both improved to a clinically meaningful degree post-treatment; these improvements persisted to the final assessment three months following drug exposure (MADRS: -9.3 ± 2.7, p = .001, g = 1.0; HAM-A: –3.8 ± 1.7; p = 0.031, g = 0.7). This study provides the first data on psilocybin’s effects in any neurodegenerative disease. Results suggest that psilocybin therapy in PD warrants further investigation.

Unlocked with Blossom Pro

Research Summary of 'Psilocybin therapy for mood dysfunction in Parkinson's disease: an open-label pilot trial'

Introduction

Bradley and colleagues situate the study within the context that Parkinson's disease (PD) causes substantial non-motor burdens, with depression and anxiety among the most common and clinically consequential symptoms. Previous clinical research on psilocybin has shown antidepressant and anxiolytic effects in major depressive disorder and in mood disturbance associated with terminal illness, and preclinical data suggest serotonergic psychedelics may promote neuroplasticity and modulate inflammation. However, people with neurodegenerative disease have been excluded from prior psilocybin trials, leaving its safety and potential efficacy in PD untested. This open-label pilot trial therefore aimed to evaluate the feasibility, safety and tolerability of psilocybin therapy in people with mild to moderate PD who also met criteria for depressive and/or anxious disorders, and to provide preliminary efficacy data on mood, motor and cognitive outcomes. The investigators used a dose-escalation design (10 mg followed by 25 mg) delivered alongside structured psychotherapeutic support, with follow-up extending to three months after the higher dose administration.

Methods

Using a single-arm, nonrandomized design, the investigators enrolled people aged 40–75 with Hoehn & Yahr stage 1–3 PD who met DSM-5 criteria for a depressive and/or anxious disorder. Key exclusions included significant cardiovascular disease, Montreal Cognitive Assessment (telephone version) score <18, current psychosis or primary psychotic disorder, history of mania, and use of concomitant medications judged to pose safety risks or to interfere with psilocybin (notably SSRIs, MAOIs, dopamine agonists and anticholinergics). Twelve participants were enrolled; the first three were not on dopaminergic therapy, and the remaining nine were on a stable carbidopa–levodopa regimen continued throughout the study. Each participant received preparatory psychotherapy with a licensed therapist, then a 10 mg oral “safety” dose of pharmaceutical-grade synthetic psilocybin. If tolerated, a 25 mg treatment dose was administered about two weeks later. Psychotherapy included preparatory sessions, between-dose sessions and integration sessions after the 25 mg administration; both psilocybin sessions were conducted on a research unit with continuous supervision, repeated vital-sign monitoring, and access to medications and a study physician for management of cardiovascular or psychiatric adverse effects. Participants remained under observation overnight after each session. The primary objective was safety and tolerability. Assessments included elicited adverse events (AEs), vital signs, the 5-Dimensional Altered States of Consciousness (5D-ASC) scale on drug days, and monitoring for suicidality (Columbia Suicide Severity Rating Scale) and psychotic symptoms (Enhanced Scale for the Assessment of Positive Symptoms in Parkinson's Disease, eSAPS-PD). Motor and non-motor PD symptoms were measured with the Movement Disorder Society–Unified Parkinson's Disease Rating Scale (MDS-UPDRS; Parts I–IV). Cognitive safety and performance were assessed with selected Cambridge Neuropsychological Test Automated Battery (CANTAB) tasks (Paired Associates Learning, Spatial Working Memory, Reaction Time, One Touch Stockings, Match to Sample) plus a Probabilistic Reversal Learning (PRL) task. Care-partner reports (NPI-Q) and treatment acceptability at three months (B90) were also recorded. Depression and anxiety were measured with the Montgomery–Åsberg Depression Rating Scale (MADRS) and Hamilton Anxiety Rating Scale (HAM-A). For analysis, mixed-effects linear models were fitted with time as a fixed effect and participant as a random effect using R and the lme4/lmerTest packages. Normality and homoscedasticity of residuals were checked but, given the small sample, could not be unequivocally confirmed. Paired t-tests compared vital signs and 5D-ASC scores between the 10 mg and 25 mg sessions. Standardised effect sizes (Hedges' g) and raw p-values are reported without correction for multiple comparisons; no a priori power calculation was performed because this was a pilot study.

View full paper sections

INTRODUCTION

Parkinson's disease (PD) is an increasingly prevalent neurodegenerative disorder and a growing cause of disability worldwide. Though classically associated with its hallmark motor symptoms, the progressive and widespread aggregation of α-synuclein in PD also leads to a broad range of nonmotor symptoms that are a major source of functional impairment. Depression and anxiety are some of the most prevalent nonmotor symptoms, and are associated with poor quality of life as well as accelerated functional decline. Unfortunately, current treatments for mood dysfunction have limited efficacy in PDand the number of clinical trials investigating novel interventions is strikingly low. The indoleamine psychedelic psilocybin has shown promising antidepressant and antianxiety effects in major depressive disorder (MDD) and terminal cancer, but no studies have reported on its effects among people with PD or any neurodegenerative disease. Once ingested, psilocybin is converted to its active metabolite, psilocin, an agonist at multiple cortical serotonin receptors including 5-HT2AR. The drug's characteristic acute subjective effects can range from euphoria, mysticaltype experiences, and pleasurable perceptual changes (e.g., synesthesia, sensory illusions) to negative emotional states and psychotic-like effects. Though intoxication resolves within approximately six hours, studies have reported that a single psilocybin administration paired with psychotherapeutic support can yield robust improvements in mood that persist long after the drug is metabolized. The mechanisms underlying these sustained effects are not well understood. A leading hypothesis characterizes psilocybin as a "psychoplastogen", i.e. a compound that catalyzes a burst of neuronal growth that can lead to enduring changes in dendritic architecture and synaptic restructuring. Preclinical evidence suggests that in addition to agonism at 5-HT2AR, modulation of glutamatergic signaling and pathways critical for regulating neuroinflammation, including the mammalian target of rapamycin (mTOR) and tropomyosin receptor kinase B (TrkB), are implicated in the neuroplasticitypromoting properties of serotonergic psychedelics. These mechanisms may be particularly relevant for targeting depression and anxiety in PD-serotonergic dysfunction, synaptic deficits, and elevated inflammation are all pathophysiological features of the disease and may contribute to the high prevalence of associated mood dysfunction. While the toxicity of psilocybin is relatively low, its safety for people with PD warrants careful evaluation. First, the drug's vasoactive effects lead to increases in heart rate and blood pressurewhich could confer elevated risk given the older age and autonomic dysfunction associated with PD. Second, it is unclear how psilocybin's modulation of serotonin signalingcould impact other symptoms of PD, as altered serotonergic system functioning is implicated both in motor impairment and in PD psychosis. Psychosis is common in the natural course of PD, developing in over 40% of those with the illness, and there is some concern that psilocybin could precipitate or worsen psychosis in people with underlying susceptibility. The drug's agonism at 5-HT2AR may be particularly problematic given that patients with PD-associated visual hallucinations have increased 5-HT2AR binding in multiple cortical areas, and medications used to treat PD psychosis have 5-HT2AR-blocking properties. Further, psilocybin interacts with other serotonin receptorslinked to tremor (5-HT1AR, serotonin transporter) and dyskinesia (5-HT1AR, 5-HT2CR) in PD, and can modulate functional connectivity between serotonin-and dopamine-regulated neural networks-these findings make it challenging to predict potential effects on motor function. Lastly, drug-drug interactions between psilocybin and levodopa, the most commonly-used and effective treatment for motor symptoms of PD, are unknown. With these considerations in mind, we conducted an open-label pilot trial using a dose escalation approach to examine the safety, tolerability, and preliminary efficacy of psilocybin therapy for mood dysfunction among people with PD.

Full Text PDF

Full Paper PDF

Create a free account to open full-text PDFs.

Create Free Account Already have an account? Sign in

Study Details

Study Type
individual
Population
humans
Characteristics
open labelfollow up
Journal
Neuropsychopharmacology
Compound
Psilocybin
Topics
Anxiety Disorders Depressive Disorders Major Depressive Disorder (MDD)Palliative & End-of-Life Distress

Results

Twelve participants completed the protocol with no missing data. There were no serious adverse events reported. Most AEs occurred during the psilocybin sessions; anxiety, nausea, headache, and transient elevations in blood pressure and heart rate were the most frequent, and none required medical intervention. Two participants experienced severe anxiety during a session. One of these reported transient increased tremor during the session and worse motor function persisting until 30 days after the 25 mg dose, and the same participant reported increased thoughts about pursuing medically assisted dying at B30; this was not classified as a serious adverse event because there was no current intent or plan. Overall suicidal ideation decreased post-treatment (average Hedges' g = 0.87). Cardiovascular responses were dose-related. Systolic blood pressure (SBP) > 160 mmHg or diastolic blood pressure (DBP) > 100 mmHg occurred in three participants after 10 mg and in six participants after 25 mg; tachycardia occurred in one participant during 10 mg and two participants during 25 mg sessions. All such episodes were asymptomatic and resolved spontaneously during the acute effect window. Compared with the 10 mg session, the 25 mg session produced significantly larger increases in average SBP (t = -3.39, p = 0.006), DBP (t = -2.23, p = 0.048) and heart rate (t = -2.71, p = 0.020). Participants’ 5D-ASC scores tended to be higher after 25 mg, but differences versus 10 mg were not statistically significant on most dimensions; comparisons with a prior major depressive disorder trial suggested somewhat higher intensity in this PD sample but without consistent significant differences. On the MDS-UPDRS, non-motor symptoms (Part I) improved markedly at one week and one month after the 25 mg session (B7: -13.5 ± 1.3, p < 0.001, g = 3.1; B30: -13.8 ± 1.3, p < 0.001, g = 3.0). Patient-reported motor function (Part II) also improved (B7: -6.8 ± 0.8, p < 0.001, g = 1.1; B30: -7.5 ± 0.9, p < 0.001, g = 1.2). Clinician-rated motor examination (Part III) showed smaller but statistically significant improvements (B7: -3.6 ± 1.3, p = 0.011, g = 0.3; B30: -4.6 ± 1.3, p = 0.001, g = 0.3). The observed changes for Parts I–III exceeded published minimal clinically important differences (MCIDs) for those scales. Cognitive performance improved on several tasks. Paired Associates Learning (PAL) showed improvement at B7 (−0.47 ± 0.14, p = 0.002, g = 0.5) and B30 (−0.44 ± 0.14, p = 0.003, g = 0.4). Spatial Working Memory (SWM) improved strongly at B7 (−0.76 ± 0.17, p < 0.001, g = 1.0) and B30 (−0.52 ± 0.17, p = 0.003, g = 0.7). Probabilistic Reversal Learning (PRL) performance increased at B7 (2.5 ± 0.9, p = 0.008, g = 1.3) and B30 (2.9 ± 0.9, p = 0.003, g = 1.3). Match to Sample improved at one month only; Reaction Time and One Touch Stockings showed no significant changes. Psychotic symptoms measured by eSAPS-PD were minimal at baseline and decreased post-treatment (B7: -1.2 ± 0.5, p = 0.033, g = 0.4; B30: -1.3 ± 0.5, p = 0.016, g = 0.5). Mood outcomes improved. Baseline MADRS was 21.0 ± 8.7 and HAM-A 17.0 ± 3.7. Depression decreased at one week and one month after the 25 mg session (MADRS B7: −7.9 ± 2.7, p = 0.007, g = 1.0; B30: −7.4 ± 2.7, p = 0.008, g = 0.8) and remained improved at three months (B90: −9.3 ± 2.7, p = 0.001, g = 1.0). Anxiety improved at one week (HAM-A B7: −4.5 ± 1.7, p = 0.012, g = 0.9) and was significantly reduced at three months (B90: −3.8 ± 1.7, p = 0.031, g = 0.7) though the one-month change did not reach statistical significance (B30: −3.2 ± 1.7, p = 0.073). The MADRS changes exceeded typical estimates of MCID for that scale. Care-partner NPI-Q ratings indicated reduced neuropsychiatric symptom severity and distress at B7, B30 and B90. Treatment acceptability was high: all participants agreed to some degree that the treatment was helpful and would recommend it, while 10 of 12 reported the treatment was challenging to some extent.

Discussion

Bradley and colleagues interpret these findings as the first empirical data on psilocybin therapy in any neurodegenerative disease, suggesting an acceptable safety and tolerability profile in this small sample of people with mild to moderate PD and comorbid mood dysfunction. No serious cardiovascular events, no worsening of psychosis, and no overall cognitive harms were observed, and the majority of adverse events were transient and comparable to prior psilocybin trials. The investigators emphasise that two participants experienced particularly challenging acute subjective effects and subsequent adverse events, underscoring the risks associated with high-dose psychedelic treatments even when delivered in a controlled setting with psychotherapeutic support. The authors note rapid and sustained improvements in depression and anxiety, which are consistent with prior psilocybin studies in major depression and cancer-related mood disturbance, and report surprising improvements in non-motor and motor PD measures as well as in several cognitive domains related to learning and cognitive flexibility. They propose multiple, non-exclusive explanations: psilocybin might directly modulate circuits relevant to motor control via serotonergic interactions with dopaminergic networks; mood improvement could secondarily enhance motor performance; or psilocybin's putative neuroplastic, anti-inflammatory and glutamatergic effects might interact with PD pathophysiology. The authors stress that mechanistic trials using neuroimaging and fluid biomarkers are required to adjudicate these possibilities. Important limitations are acknowledged: the small sample size, single-arm open-label design and attendant risk of expectancy and placebo effects (which are prominent in both psychedelic research and PD trials); restrictive eligibility criteria that excluded people with dementia, significant cardiovascular disease and many concomitant medications; and poor racial and ethnic diversity. The combined intervention (psilocybin plus psychotherapy) precludes separating drug effects from psychotherapeutic contributions, and the chosen dosing strategy (10 mg then 25 mg) leaves unanswered questions about dose–response and the necessity of an intense subjective experience for clinical benefit. For these reasons the authors call for well-powered randomized controlled trials, mechanistic studies, dose–response investigations and broader inclusion criteria to determine efficacy, safety across disease stages, optimal protocols and generalisability.

PATIENTS AND METHODS STUDY DESIGN AND PARTICIPANTS

This was a single-arm, nonrandomized trial. The trial protocol can be found in Supplement 1; the design is illustrated in Fig.. Briefly, we enrolled people ages 40-75 with mild to moderate PD (Hoehn & Yahr stages 1-3) who also met criteria for a depressive and/or anxious disorder according to the Diagnostic and Statistical Manual, 5th Edition. Key exclusion criteria included significant cardiovascular disease, cognitive impairment (Monteal Cognitive Assessment -telephone version score <18), use of concomitant medications that could pose a safety risk or interfere with psilocybin's effects (including serotonin reuptake inhibitors, monoamine oxidase inhibitors, dopamine agonists, and anticholinergics), history of mania or a primary psychotic disorder, or current psychosis involving loss of insight. Twelve eligible participants were included in the study. The first three participants were not treated with any dopaminergic therapy for motor symptoms of PD. Following review of safety and tolerability Fig.Study design and participant flow diagrams. A After screening and baseline assessments, participants completed a 10 mg psilocybin administration session (A0) followed by a 25 mg psilocybin administration session (B0) approximately two weeks later. Participants also completed a series of psychotherapy meetings as part of the treatment: two meetings were scheduled before A0, two between A0 and B0, and then three following B0. Key follow-up time points are shown: one week after the 10 mg session (A7), one week after the 25 mg session (B7), one month after the 25 mg session (B30), and three months after the 25 mg session (B90). B The five most common reasons for ineligibility after prescreening were using exclusionary medications, not having a diagnosis of PD, not meeting criteria for either depression or anxiety, not being able to commit to the study schedule, and significant cognitive impairment. outcomes for these individuals, we opened enrollment to people treated with levodopa formulations. All nine subsequent participants were on a stable carbidopa-levodopa regimen which they continued throughout the study, including during psilocybin sessions. The study was approved by the US Food and Drug Administration and the University of California, San Francisco (UCSF) Institutional Review Board. All participants provided written informed consent.

PROCEDURES

The study investigational drug was pharmaceutical grade synthetic psilocybin 3-[2-(dimethylamino)ethyl]-1H-indol-4-yl] dihydrogen phosphate developed by Usona Institute (Madison, WI, USA). After screening and baseline assessments, each participant was paired with a licensed therapist with whom they had multiple meetings. Key components of the psychotherapy component of treatment include preparatory rapportbuilding and psychoeducation about psilocybin, attention to details of the physical space in which psilocybin administration occurs to optimize comfort and safety, and discussion of the meaning and impact of the psilocybin experience following each session, in line with prior studies of psilocybin therapy for mood dysfunction. Each participant met with their therapist three times prior to the first psilocybin session, had another two meetings between the first and second psilocybin sessions, and then three meetings following the second psilocybin session (see Fig.and Supplement 2 for details of the psychotherapy component of treatment). Each participant first received a 10 mg oral safety dose of psilocybin. If this was well-tolerated, they were eligible for a 25 mg treatment dose approximately two weeks later. Procedures for both psilocybin sessions, conducted on a research unit at UCSF, were identical. Following assessment of vital signs and a urine drug screen, the participant ingested the psilocybin capsule in a quiet room with their therapist present. The therapist provided safety monitoring and psychological support throughout the period of acute drug effects, reporting to an onsite study physician at regular intervals. Vital signs were assessed at baseline and at 30, 60, 90, 120, 240, 360, and 420 minutes following psilocybin administration. Medications to address treatment-emergent cardiovascular effects, agitation, and psychotic symptoms were available. A neurologist specializing in movement disorders was available for consultation by telephone. The participant remained in the research unit under continuous supervision throughout the period of acute drug effects and overnight following both psilocybin sessions. In the morning, the physician conducted a safety evaluation before discharging the participant to their care partner.

ASSESSMENTS

Our primary objective was to evaluate the safety and tolerability of psilocybin therapy. We elicited adverse events (AEs) at all study visits and assessed vital signs and subjective experience via the 5-Dimensional Altered States of Consciousness (5D-ASC) rating scaleon each drug administration day. We used additional assessments to further evaluate safety and tolerability at key follow-up timepoints: one week after the 10 mg psilocybin session (A7), one week after the 25 mg session (B7), and one month after the 25 mg session (B30). Specifically, we monitored for changes in PD symptoms using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS), a comprehensive tool designed to detect changes associated with disease progression or treatment response that consists of four sections, each evaluated separately: Parts I (clinician and patient report) and II (patient report) capture nonmotor and motor functional impairment. Part III is a clinician motor examination, and Part IV a clinician and patient report of motor complications associated with treatment. Participants treated with carbidopa-levodopa completed all instances of the MDS-UPDRS during motoric "on" periods, and all motor examinations for a given participant were scored by the same trained rater. Suicidality and psychotic symptoms were monitored using the Columbia Suicide Severity Rating Scale (CSSRS)and the Enhanced Scale for the Assessment of Positive Symptoms in Parkinson's Disease (eSAPS-PD), respectively. To assess cognitive safety, we used the Cambridge Neuropsychological Test Automated Battery (CANTAB), specifically: (1) Paired Associates Learning (PAL; domain: visual learning), (2) Reaction Time Simple and Five Choice (RTI; attention and psychomotor speed), (3) One Touch Stockings of Cambridge (OTS; executive function), (4) Spatial Working Memory (SWM), and (5) Match to Sample (MTS; attention and psychomotor speed); see Supplement 2 for details of CANTAB tasks. As PD is associated with impaired cognitive flexibilitywe also administered a Probabilistic Reversal Learning (PRL) taskto assess for changes in this domain. Care partners' observations of participants' behavior were captured by the Neuropsychiatric Inventory Questionnaire (NPI-Q), and both participants and care partners reported on treatment acceptability three months after the 25 mg session (B90); see Supplement 1, Appendix A for the study-specific questionnaire. To evaluate preliminary efficacy for mood dysfunction, we used the Montgomery-Åsberg Depression Rating Scale (MADRS)and the Hamilton Anxiety Scale (HAM-A). In addition to the key timepoints listed above, the MADRS, HAM-A, and NPI-Q were also administered three months after the 25 mg session (B90).

SAFETY AND TOLERABILITY OUTCOMES

We observed no serious AEs. The majority of AEs occurred during psilocybin sessions-anxiety, nausea, headache, as well as blood pressure and heart rate elevations were most common (Table). None required medical intervention. One participant reported an increase in tremor that resolved spontaneously within the period of acute drug effects. Two participants experienced severe anxiety during one of their psilocybin sessions. One of these participants also reported increased tremor throughout the first session and worse motor function following each session which persisted until 30 days following the 25 mg psilocybin administration session. MDS-UPDRS ratings, however, did not indicate worse motor function. The same participant also reported an increase in suicidal ideation per the CSSRS at the B30 time point. Specifically, the participant reported increased thoughts about pursuing medically assisted dying when PD led to disability in the future. As they did not endorse a current desire to die or intent to act on a plan for self-harm, this was not considered a serious AE. In the sample overall, suicidal ideation decreased significantly posttreatment (average Hedges' g = 0.87). The other participant who experienced severe anxiety during the 25 mg psilocybin session also reported multiple AEs in the subsequent weeks including anxiety, dry mouth, sleep disruption, an unspecified sensory disturbance, and feeling abnormal. Systolic blood pressure (SBP) > 160 mmHg or diastolic blood pressure (DBP) > 100 mmHg occurred among three participants following administration of psilocybin 10 mg and among six participants following psilocybin 25 mg (see Fig.and Tablein Supplement 2). Tachycardia occurred in one and two participants during the 10 mg and 25 mg sessions, respectively. All participants were asymptomatic during these episodes, and blood pressure elevations and tachycardia resolved spontaneously within the period of acute drug effects. In the sample overall, there were significantly larger increases in average SBP (t = -3.39, p = 0.006**), DBP (t = -2.23, p = 0.048*), and HR (t = -2.71, p = 0.020*) during the 25 mg session relative to the 10 mg session. Participants' ratings of the intensity of subjective experience tended to be higher following the 25 mg psilocybin session, but were not significantly different relative to ratings following the 10 mg session. For comparison, we examined 5D-ASC scores from a previous trial of psilocybin therapy for MDDthat also administered a 25 mg dose. Participants in the current study tended to report higher intensity, but differences were not significant on most dimensions (Fig.in Supplement 2). Non-motor symptoms were significantly improved at the oneweek as well as at the one-month follow-up (MDS-UPDRS Part I at B7: -13.5 ± 1.3, p < 0.001***, g = 3.1; at B30: -13.8 ± 1.3, p < 0.001***, g = 3.0); see Tableandandin Supplement 2. Motor symptoms were also significantly improved at both time points (Part II at B7: -6.8 ± 0.8, p < 0.001***, g = 1.1; at B30: -7.5 ± 0.9, p < 0.001***, g = 1.2). Motor examination scores improved significantly as well, although with smaller effect sizes (Part III at B7: -3.6 ± 1.3, p = 0.011*, g = 0.3; at B30: -4.6 ± 1.3, p = 0.001**; g = 0.3); see Fig.. For reference, Part III scores are estimated to worsen by approximately 2.4 points per year during the first five years following diagnosis. Observed improvements for Parts I, II, and III all meet thresholds for the minimal clinically important difference (MCID;: 2.64, 3.05, and 3.25 points, respectively). Motor complication scores were All treatment-emergent adverse events determined to be definitely, probably, or potentially related to the study drug are included and classified using MedDRA Preferred Terms. a Elevated blood pressure events reflect instances of a systolic blood pressure reading 160 bpm or a diastolic 100 bpm at any time during the psilocybin administration session. There were no systolic blood pressures 180 bpm or diastolic 120 bpm in any session. b Adverse events >14 days following the psilocybin mg administration session are marked "NA" as participants completed the psilocybin 25 mg administration session approximately 14 days later. c Note that the instance of suicidal ideation was not reported as a serious adverse event given that the participant endorsed no intent nor any suicidal behavior. minimal at baseline (consistent with mild-moderate disease stages; Part IV mean ± SD: 1.3 ± 2.6), and tended to decrease, but not significantly so (at B7: -0.5 ± 0.3, p = 0.083; at B30: -0.5 ± 0.3, p = 0.083). Psychotic symptoms were minimal at baseline (mean ± SD: 2.3 ± 3.5) and were significantly reduced post-treatment (at B7: -1.2 ± 0.5, p = 0.033, g = 0.4; at B30, -1.3 ± 0.5, p = 0.016, g = 0.5). Performance was significantly improved post-treatment on Paired Associates Learning (PAL at B7: -0.47 ± 0.14, p = 0.002**, g = 0.5; at B30: -0.44 ± 0.14, p = 0.003**, g = 0.4), Spatial Working Memory (SWM at B7: a Follow-up time points were one week after the 10 mg psilocybin session (A7), one week after the 25 mg psilocybin session (B7), and one month after the 25 mg psilocybin session (B30). Select measures were also collected at the three month follow-up time point (B90). -0.76 ± 0.17, p < 0.001***, g = 1.0; at B30: -0.52 ± 0.17, p = 0.003**, g = 0.7), and Probabilistic Reversal Learning (PRL at B7: 2.5 ± 0.9, p = 0.008**, g = 1.3; at B30: 2.9 ± 0.9, p = 0.003**, g = 1.3); see Fig., Tablesandandin Supplement 2. Performance on Match to Sample (MTS) was significantly improved at the one-month follow-up only, and there were no significant changes for the other two cognitive tasks (Reaction Time [RTI] and One Touch Stockings of Cambridge [OTS]). Care partners reported significant improvements at both oneweek and one-month follow-ups in the severity of neuropsychiatric symptoms (at B7: -5.1 ± 1.0, p < 0.001***, g = 1.5; at B30: -4.1 ± 1.0, p < 0.001***, g = 1.3) and associated distress (at B7: -5.3 ± 1.3, p < 0.001***; at B30: -3.5 ± 1.3, p = 0.012*, g = 0.8) of the NPI-Q. Improvements persisted to the three-month follow-up (severity at B90: -5.2 ± 1.0, p < 0.001***; g = 1.8; distress at B90: -6.2 ± 1.3, p < 0.001***, g = 1.6). The acceptability questionnaire, administered at the end of the study (B90), indicated that all participants agreed to some degree that the treatment was helpful and that they would recommend it to others. Ten of twelve participants found the treatment challenging to some extent (strongly agree: n = 5; agree: n = 3, somewhat agree: n = 2); one responded neutrally and one disagreed (see Figurein Supplement 2).

DISCUSSION

To our knowledge, this is the first empirical report on the effects of psilocybin among people with PD. The intervention had a strong safety and tolerability profile in this sample: we did not observe concerning acute cardiovascular effects of psilocybin, worsening or emergence of psychotic symptoms, or negative effects on cognitive performance. We also did not find worsening of PD symptoms overall-on the contrary, participants experienced improvements in both non-motor and motor symptoms that persisted to the final assessment one month following drug administration. Improvements in mood dysfunction were rapid relative to standard pharmacotherapy, becoming apparent within one week of drug administration, and sustained to the final assessment three months later. Care partners' ratings also indicated improvement in neuropsychiatric symptoms that persisted for at least three months. Lastly, treatment satisfaction was high. Most AEs occurred during psilocybin sessions and were comparable in frequency, severity, and duration to prior psilocybin trials. Tolerability was similar among participants not using dopaminergic treatment (n = 3) and those on concomitant carbidopa-levodopa (n = 9). Though it is reassuring that psychotic symptoms did not worsen following psilocybin, it must be noted that participants had mild to moderate PD severity and minimal psychotic symptoms at baseline-additional research with people at varying disease stages is needed to fully characterize psilocybin's effects on PD psychosis. In addition, though psilocybin was well-tolerated overall, two participants endorsed particularly challenging acute subjective experiences and experienced AEs during the follow-up period. For one participant, this included thoughts about pursuing medically assisted dying in the future. The experiences of these participants underscore the risks associated with high-dose psychedelic treatments, even when provided using a consistent medicinal product in a monitored setting and paired with skilled psychotherapeutic support. Of note, there was a non-significant trend towards more intense subjective effects among participants in this study (relative to a prior psilocybin study in major depression). Research to uncover psilocybin's mechanisms of action and identify predictors of treatment response will be essential for determining its real-world clinical utility. We observed significant and sustained improvements in depression and anxiety, consistent with prior studies of psilocybin therapy for major depression and mood dysfunction associated with terminal cancer. Anecdotally, multiple participants described feeling better able to adapt to health-related challenges post-treatment. This may be particularly important for people with PD, who commonly experience demoralization that can interfere with the adaptive disease management that optimizes function. While mood and cognition changes did not correlate significantly in this sample, participants' cognitive flexibility improved post-treatment and prior work suggests that enhanced cognitive flexibility may be a mechanism by which psilocybin therapy produces lasting benefits on well-being. Given the improvements that we observed in mood, the improvements in nonmotor symptoms are somewhat expected, as this cluster includes depression and anxiety plus issues that frequently overlap with mood dysfunction (i.e., fatigue, sleep problems, and apathy). The large effect on nonmotor symptoms likely reflects the fact that participants had a relatively high nonmotor burden at baseline (whereas baseline depression and anxiety scores were near the mild/moderate cusp). Though future studies enrolling people with more severe mood dysfunction are essential, the observed effects on depression and anxiety suggest that psilocybin therapy may have the potential to address a critical gap in PD care. The improvements in participants' motor symptoms as well as their motor exams from pre-to post-treatment were surprising. One possible explanation is that psilocybin could provide some degree of motor symptom relief. The drug modulates dopamineregulated brain networks through its interactions with multiple serotonin receptor subtypes, and other treatments for mood dysfunction (i.e., paroxetineand electroconvulsive therapy [ECT]) have been shown to ameliorate motor symptoms in PD, likely via modulation of serotonergic and dopaminergic signaling, respectively. If this is the case, a sustained effect weeks after exposure to the drug is somewhat unexpected, although there are reports of motoric benefits from ECT lasting up to two months. A second possibility is that improved mood could lead to improved motor function. Depression itself is hypothesized to increase allostatic load through hypothalamic pituitary axis activation, inflammatory changes, mitochondrial dysfunction, and downregulation of neurotrophic factors, ultimately resulting in neurodegeneration. Interestingly, the "depressed frail phenotype" observed in older adults (without PD) is associated with multiple markers of accelerated aging, including impaired dopaminergic neurotransmission. Mood dysfunction often precedes the development of motor symptoms of PD by several years and people with depression or anxiety earlier in life are twice as likely to develop PD. These observations offer support for the hypothesis that mood dysfunction could reflect a separate pathophysiological process that is a risk factor for PD. A third potential explanation is that psilocybin impacts the pathophysiology of PD itself. The drug has been shown to modulate glutamatergic activity in prefrontal circuits, reduce inflammatory activity, induce gene expression relevant for neuroplasticity pathways, and promote neuronal growth. Each of these may be important mechanisms contributing to its effects on depression and anxiety, but could also interact with PD pathophysiology: impaired glutamate homeostasis, dysregulated inflammation, and reduced synaptic plasticity are key elements of the neurodegenerative process in PD. An alternative to the risk factor hypothesis of mood dysfunction in PD is the prodromal hypothesis, which posits that mood changes are a direct consequence of PD pathology that often manifest early in the course of illness. If this is true, it is possible to imagine that the effects we observed-on mood, on other nonmotor symptoms, and on motor symptoms-are the result of psilocybin modulating common mechanisms that drive these clinical features. Mechanistic trials (utilizing functional neuroimaging, neurophysiological paradigms, cerebrospinal fluidand blood-based markers) that enroll PD patients with and without mood dysfunction are needed to examine each of these possibilities. There are several important limitations of this study. First, the small sample size and open-label design mean that all findings must be interpreted with caution. Positive expectancy is a well-documented source of placebo response in psychedelic studiesand placebo effects are common in PD treatment. Well-powered randomized controlled trials are critical to mitigate bias and determine the efficacy of psilocybin therapy. Second, this sample was comprised of people with mild to moderate PD and excluded dementia, serious complications of cardiovascular disease, and multiple concomitant medications. Future trials can consider careful expansion of medical inclusion criteria. Third, though gender diversity was adequate, racial and ethnic diversity was poor, exacerbating a major problem in psychedelic research. Active engagement of minoritized and underrepresented groups is essential to ensure that study samples reflect the population of people with PD. Fourth, the parameter space of psilocybin therapy is not yet well-defined. We selected a therapeutic dose of 25 mg based on prior studies, though some participants experienced meaningful benefits following the 10 mg administration. While 25 mg reliably produces an intense subjective experience, whether that experience is critical for clinical improvement is unclear. Further, this study treated psilocybin therapy as a combined intervention (psilocybin plus psychotherapy sessions) and thus the relative contributions of the drug versus psychotherapy cannot be determined. Larger, controlled studies examining doseresponse and extra-pharmacologic effects will be important for developing treatment protocols that maximize clinical benefit while mitigating risks to patients. In conclusion, results of this initial pilot study suggest that psilocybin therapy may have promise as a new treatment for mood dysfunction in PD, but rigorous efficacy testing is a crucial next step. Findings also raise the possibility that psilocybin could have cognitive and motoric benefits. Preclinical evidence that psychedelics have anti-inflammatory effects, upregulate neurotrophic factors, and enhance synaptic plasticity has stimulated interest in their application to neurodegenerative disorders [102, 103], but whether these changes could translate to clinical improvements is unknown. This study supports further investigation of psilocybin's effects in PD.

Company

Product

Legal

Psilocybin therapy for mood dysfunction in Parkinson's disease: an open-label pilot trial

Authors

Published

Links

Related Clinical Trial

Psilocybin Therapy for Depression and Anxiety in Parkinson’s Disease (PDP)

References (27)