Psychedelic drug use in healthy individuals: A review of benefits, costs, and implications for drug policy

Researchers and clinicians have increasingly revisited the therapeutic potential of psychedelic drugs after a long hiatus following restrictive drug laws in the 1960s. Earlier clinical work from the 1950s and 1960s produced many suggestive but methodologically imperfect findings that psychedelics could help mood, anxiety, and addictive disorders; more recent controlled studies have begun to corroborate beneficial effects. At the same time, bioethical debate about pharmacological enhancement in healthy people has largely focused on pharmaceuticals such as SSRIs, which produce limited and typically small mood-enhancing effects in non-clinical populations and require long-term use. Elsey sets out to fill a gap in contemporary discussion by reviewing evidence about psychedelic effects specifically in healthy individuals. The review aims to summarise what is known about the psychedelic state, underlying neurobiology, psychological and behavioural effects in non-clinical samples, possible adverse outcomes, and the policy implications of these findings in order to ground ethical and legal debates in the available empirical literature.

This paper is a narrative review of contemporary research concerning psychedelic drug effects in healthy individuals. The extracted text describes the topics covered — the phenomenology of the psychedelic state, neurobiological findings from human imaging and pharmacology, experimental and observational studies of psychological and behavioural effects in healthy volunteers and ritual users, adverse-event reports and population studies, and legal/policy discussion — but does not report a formal literature search strategy, inclusion/exclusion criteria, databases searched, or dates covered. Because an explicit systematic search or meta-analytic method is not described in the extracted text, the review should be understood as a synthesis of selected historical and contemporary studies and case reports rather than a systematic review. The author draws on experimental laboratory studies (including controlled administration and follow-ups), cohort and cross-sectional observational data from ritual contexts, pooled analyses of experimental participants, and individual case reports when discussing risks and longer-term outcomes.

Elsey summarises evidence across neurobiology, acute and longer-term psychological effects in healthy people, adverse outcomes, and population-level data. Neurobiology: Human brain imaging studies during the acute psychedelic state (LSD, psilocybin, ayahuasca/DMT) consistently implicate changes in the default mode network (DMN), particularly reduced integrity or connectivity of hubs such as the posterior cingulate cortex (PCC) and medial prefrontal cortex (mPFC). Psychedelics appear to decrease organised activity within the DMN while increasing connectivity between networks that are normally more segregated, a pattern correlated with altered conscious experience. Higher signal diversity measures (magnetoencephalography) have been observed during LSD, psilocybin or ketamine states and related to subjective intensity. Convergent pharmacological evidence implicates serotonin 2A (5-HT2A) receptor agonism as a primary mechanism: brain regions affected by psychedelics show high 5-HT2A density, and the 5-HT2A antagonist ketanserin completely blocked LSD’s subjective effects in one study. Animal data cited indicate repeated LSD can down-regulate 5-HT2A expression in prefrontal cortex, a change linked to depression and stress resilience. Psychological and behavioural effects in healthy individuals: Experimental and historical studies report that single supervised doses can induce profound acute experiences, including 'complete mystical experiences' characterised by unity, ineffability, transcendence of time/space, noetic quality and intense positive mood. In follow-ups up to 14 months, substantial proportions of participants judged the experience highly significant: for example, 58% rated it among the five most personally significant experiences, 67% as among the most spiritually meaningful, and 64% reported increased wellbeing and life satisfaction. Controlled laboratory work found dose-related increases in mystical-type and wellbeing measures with LSD and psilocybin. Studies also report changes in personality measures such as increases in openness following reduced organisation of brain activity during the acute phase. Cognitive, social and creative effects: While participants under LSD showed impaired recognition of fearful faces and some reduction in cognitive empathy (theory of mind), they displayed increased emotional empathy, prosocial choices in allocation tasks, and greater feelings of trust and closeness. Music amplified emotive responses under LSD in one study, illustrating the importance of set and setting. Experimental and ritual-context studies suggest psychedelics can enhance aspects of creative thinking and problem solving: an historical mescaline study reported real-world problem solutions, and an ayahuasca study found increased originality on a standard creativity test two weeks after sessions. Adverse effects and risk: The review aggregates controlled-trial data, ritual-context surveillance and case reports. Acute adverse reactions such as paranoia or panic occur in a minority and typically resolve within the session; in some experimental series a measurable subset experienced transient panic but no lasting harm. Pooled analysis of 110 experimental psilocybin participants found strong dysphoria or panic only at the highest doses in a small number. Case reports exist of psychotic episodes or self-harm following ayahuasca or synthetic psychedelics, but these cases commonly involved concurrent or antecedent factors (heavy cannabis or alcohol use, family history of psychosis) and are difficult to attribute solely to psychedelics. Surveillance in a religious setting (União do Vegetal) reported psychotic incidents of approximately 0.05–0.1% over five years (estimated from ~25,000 sessions), and another dataset reported 29 psychosis-feature cases from an estimated 1.56 million ayahuasca doses, of which 19 were plausibly precipitated by ayahuasca; many cases had premorbid risk factors. Large-scale population studies cited found no association between lifetime psychedelic use and mental health problems or suicidality; one study even reported lower psychological distress and suicidality after controlling for covariates. No evidence was found for a meaningful risk of hallucinogen persisting perceptual disorder (HPPD) in pooled experimental data or population studies. Regarding dependence, classic psychedelics are not considered addictive and are being investigated as addiction treatments. Longer-term neural and cognitive correlates: Cross-sectional work in ritual ayahuasca users reported lower cortical thickness in the PCC and associations with spirituality, while those users sometimes outperformed non-users on neuropsychological tests; causal direction could not be established in these designs. Policy-relevant observations: The author notes widespread lifetime psychedelic exposure (over 30 million historically, and an estimate of 32 million US individuals having used a psychedelic at least once in 2010) and argues that strict prohibition does not align with the evidence base on relative harms and possible benefits. The review highlights that current laws also impede research, particularly in healthy populations.

Elsey interprets the compiled evidence as indicating that psychedelics, when administered at appropriate doses in supervised conditions, have a favourable safety profile and the potential to improve wellbeing in otherwise healthy individuals. The review emphasises that single doses can produce lasting increases in meaning, life satisfaction and personality openness, and that the acute disorganisation of brain networks — particularly disruption of the DMN and 5-HT2A receptor-mediated effects — may underpin both the intense subjective experience and subsequent positive changes. The author situates these findings relative to earlier literature by noting that historical clinical enthusiasm was curtailed by policy rather than solely by empirical failure; contemporary controlled studies now better support therapeutic benefits and reveal comparable positive effects in healthy samples. At the same time, Elsey acknowledges uncertainties and limitations: many early studies were methodologically imperfect, some contemporary findings derive from small samples or cross-sectional designs that cannot establish causality, and case reports of adverse events are difficult to interpret because of confounding factors such as polysubstance use or pre-existing vulnerability. The extracted text also notes that excessive or intrusive measurement during sessions could alter the setting and potentially reduce positive outcomes. Policy implications emphasised by the author include questioning strict prohibition that does not reflect relative risks, the logical problems of narrow religious and therapeutic exemptions, and the difficulty of distinguishing treatment from enhancement in law. Elsey summarises arguments for broader recognition of cognitive liberty and suggests alternative regulatory options: evidence-based classification of drugs by harms and benefits, controlled administration models with trained supervisors and certification, monitored production and purity, and tax/regulatory frameworks to reduce harms from illicit markets. The author flags that rational policy should reduce incentives for novel psychoactive substances of unknown risk and should facilitate research, including studies in healthy subjects, to better characterise mechanisms and optimise safe use. Limitations and future research needs highlighted include the need for larger controlled trials in healthy populations, longitudinal work to establish causality for observed neural and psychological changes, clearer identification of risk factors that predispose to adverse outcomes (for example, psychotic or bipolar vulnerability), and systematic investigation of dose, set and setting variables that moderate benefits and harms.

Elsey concludes that psychedelic drugs are not only promising as therapeutic agents but can also produce positive and lasting effects in healthy individuals when used appropriately. The author argues for drug policy reform grounded in empirical evidence of harms and benefits, noting that rational reclassification and regulated frameworks could facilitate both therapeutic research and the safe, enriching use of psychedelics more generally.