Dimethyltryptamine (DMT): Subjective effects and patterns of use among Australian recreational users

The study recruited Australian residents aged 18 years or older who reported at least one lifetime use of DMT. Data collection took place between July and August 2009. Participants (n = 121) were recruited using snowball sampling and an advertisement in an Australian hallucinogen-related internet newsletter that linked to an anonymous online questionnaire. The study followed National Health and Medical Research Council ethics guidelines for human research. A self-administered online questionnaire of about 25 minutes comprised four main sections: demographics; history of other drug use (including past 12 months, 6 months and 30 days); DMT-specific history (age at initiation, number of occasions, routes, sources and locations); and patterns of use and attitudes (reasons for first use, perceived positive/negative aspects, perceived risks and harm reduction). Items about DMT distinguished smoked DMT from ayahuasca; respondents who had used both completed both route-specific sections. Cannabis dependence in the previous 30 days was measured using the 5-item Severity of Dependence Scale (SDS) adapted for cannabis, with the authors using a cut-off score of ≥4 to increase specificity. Analyses were predominantly descriptive. Categorical variables were reported as percentages. For continuous variables assumed normally distributed, means, standard deviations and t-tests were used; skewed continuous variables were summarised by medians and ranges with Mann–Whitney U-tests. Open-ended qualitative responses were coded into themes and reported as percentages. Unless otherwise stated, item response denominators were n = 121.

One hundred and twenty-one lifetime DMT users completed the survey; 86% were male and the median age was 28 years (range 18–68). Most respondents were Australian-born (86.8%), nearly three-quarters (73.6%) reported no religious affiliation, and 60.3% had completed some university or higher education. Employment status varied with 35.5% in full-time work and 34.8% in part-time or casual roles. Respondents reported extensive lifetime polydrug use: the mean number of distinct drugs ever tried was 17.3 (range 4–34), with 92 discrete drugs named. Nearly all (98.3%) reported lifetime alcohol and cannabis use; 89.3% and 73.6% had used alcohol and cannabis in the previous 30 days respectively. Reported lifetime use was high for LSD (96.7%), psilocybin mushrooms (91.7%), MDMA (94.2%), methamphetamine (83.5%), cocaine (72.7%), and many other classes. Using an SDS cut-off of ≥4, 26.4% met criteria suggestive of cannabis dependence in the past 30 days. Lifetime intravenous drug use was reported by 28.1% of respondents. Specific to DMT, the median age of initiation was 24 years and the median total occasions of use was 10 (range 1–400). Smoking was by far the most frequent route (98.3%); 30.6% had consumed ayahuasca. Less common routes were insufflation (5%) and injection (2.5%). The median number of occasions smoking DMT was 8, while the median number of ayahuasca occasions was 4. Ayahuasca users had smoked DMT on significantly more occasions than non-ayahuasca users (median 30 versus 6, U = 732, p < 0.001) and, overall, ayahuasca users reported greater cumulative DMT exposure. Usual sources for obtaining DMT were friends (60.3%), acquaintances (9.1%), and friends who were dealers (14.9%); 26.4% reported extracting DMT themselves from plant material. Among respondents who provided a street price, the median reported price for 1 g of ready-to-consume DMT was $150 (range $35–$1000). The ease of obtaining plant material or DMT varied across respondents. Motivations for first trying DMT (n = 103 coded responses) were predominantly general interest in hallucinogens (46.6%) and curiosity about DMT's effects (41.7%); 31.1% cited perceived psychotherapeutic benefits and 29.1% cited spiritual motivations. Regarding context of use, the most common locations were one's own home (81.8%), outdoors (55.4%) and friends' homes (52.1%). Many users reported using DMT alone at times (52.1%); those who commonly used alone had a higher median number of occasions than those who did not (median 20 versus 5, U = 971, p < 0.001). For smoked DMT, common administration methods were waterpipe/bong (55.5%), glass pipe (54.6%) and in a cigarette/joint (29.4%). Around 68.1% reported commonly smoking DMT with other drugs; cannabis was the most frequent concomitant substance (53.1%), followed by LSD (28.4%) and alcohol (27.2%). Forty-two percent of DMT smokers reported concomitant use of an MAO inhibitor such as Banisteriopsis caapi or Peganum harmala. When asked for up to five positive aspects of smoked DMT (n = 98), 75.5% reported increased personal or spiritual insight and 54.1% reported spiritual experiences; other positives included euphoria (29.6%), brief duration (27.6%) and intense visual hallucinations (21.4%). Negative aspects of smoked DMT (n = 103) most commonly concerned difficulties with smoking (49.6%) such as bad taste and coughing, and psychospiritual conflict (23.5%); 10.9% reported marked anxiety or stress during experiences. Among ayahuasca users (n = 37), 73% reported using B. caapi and 54.1% reported P. harmala as MAO inhibitors. Unlike smoked DMT, 73% of ayahuasca users reported not usually combining it with other drugs. Positive aspects of ayahuasca (n = 30) included personal insight (46.7%), psychological cleansing or catharsis (≈33%), and a smoother onset/longer duration (30%). The most commonly cited negative aspect was putrid taste and associated nausea (44%); long duration was also a negative for 20%. On perceived safety, most respondents considered their own DMT use to be safe: 54.5% rated it very safe, 38% quite safe and 6.6% moderately safe. No participant reported seeking medical attention because of DMT, and one ayahuasca user (2.7% of ayahuasca users) reported having driven under the influence. When asked about main risks (n = 111), the most frequently cited concerns were having a bad trip (50.5%), psychospiritual problems (39%), and aversive physiological reactions (26.3%). Suggested harm-minimisation strategies emphasised education (50.5%), presence of another person or 'sitter' (34.7%), appropriate mindset and setting (each 28.4%), and limiting use (29.5%).

Cakic and colleagues interpret their findings as the first comprehensive characterisation of recreational DMT use among an Australian sample, noting that users in this study were generally educated and employed rather than socially marginalised. The investigators highlight that smoking is the predominant recreational route of administration, while ayahuasca is used by a minority; most ayahuasca users had also smoked DMT, suggesting a pattern in which smoked use commonly precedes oral ceremonial use, although the authors caution that this requires further study. Peer networks were emphasised as central to initiation and propagation of DMT use: friends were the principal source of information about DMT and a strong positive correlation existed between the number of friends who had tried DMT and an individual's number of occasions of use. The researchers also draw attention to concomitant use patterns, noting frequent combinations of smoked DMT with cannabis or other hallucinogens and occasional co-administration with plant MAO inhibitors, which may be intended to prolong effects but whose motivations remain unclear. The authors position reported positive effects—especially increased personal or spiritual insight—in line with previous findings from ritual ayahuasca use. Route-specific negatives were acknowledged: smoking-related respiratory irritation and poor taste for smoked DMT, and nausea/emesis for ayahuasca; psychospiritual conflict was a cross-cutting negative effect for some users. Perceived risks were predominantly psychological, centred on frightening acute experiences and longer-lasting psychospiritual disturbances that may be difficult to integrate, particularly when use occurs in unsupportive environments. Cakic and colleagues note safety and purity concerns about illicit DMT preparations, emphasising that material extracted from plants may contain multiple tryptamines (for example 5-MeO-DMT) and that many users extract DMT without formal chemical training. The authors therefore flag uncertainty about the chemical composition of what respondents labelled as DMT as an important limitation for interpreting safety. They also acknowledge sampling limitations: snowball recruitment likely introduced bias (for example the sample was predominantly male), so it is unclear how representative the findings are of all Australian DMT users. Finally, the investigators suggest priorities for future research, including examination of users' psychological characteristics, motivations, awareness of drug interaction risks (notably MAO inhibitor interactions), and systematic assessment of benefits and harms associated with recreational DMT use.

The study concludes that, among this sample of Australian recreational users, smoking is the most common route of DMT administration while ayahuasca use is less frequent and often accompanied by prior smoking experience. DMT use in this population is embedded within extensive polydrug patterns, but is generally not experienced as addictive; many users seek psychospiritual insight. The authors recommend further research to clarify the psychological profile of recreational users, motivations for use, the real-world purity and composition of illicit DMT products, and the actual benefits and harms associated with different routes of use.