A recent large population study of 130,000 adults in the United States failed to find evidence for a link between psychedelic use (lysergic acid diethylamide, psilocybin or mescaline) and mental health problems. Using a new data set consisting of 135,095 randomly selected United States adults, including 19,299 psychedelic users, we examine the associations between psychedelic use and mental health. After adjusting for sociodemographics, other drug use and childhood depression, we found no significant associations between lifetime use of psychedelics and increased likelihood of past year serious psychological distress, mental health treatment, suicidal thoughts, suicidal plans and suicide attempt, depression and anxiety. We failed to find evidence that psychedelic use is an independent risk factor for mental health problems. Psychedelics are not known to harm the brain or other body organs or to cause addiction or compulsive use; serious adverse events involving psychedelics are extremely rare. Overall, it is difficult to see how prohibition of psychedelics can be justified as a public health measure.
The classical psychedelics lysergic acid diethylamide (LSD), psilocybin (magic mushrooms) and mescaline (peyote and other cacti) have their primary mechanism of action at the serotonin 2A (5-HT2A) receptor, elicit similar, often indistinguishable effects and show cross-tolerance (Bonson, 2012). Over 30 million adults in the United States (US) have tried psychedelics (approximately one in six adults aged 21–64 years) (Krebs and Johansen, 2013a).
Psychedelics are not known to harm the brain or other body organs or to cause addiction or compulsive use (Halberstadt, 2015; Bonson, 2012). Psychedelics are well known for inducing profound effects on the mind, which sometimes include confusion and emotional turmoil (McWilliams and Tuttle, 1973). Both the European Monitoring Center for Drugs and Drug Addiction (EMCDDA) and the health authorities in the Netherlands, where hundreds of thousands of servings of psilocybin mushrooms are legally sold in shops each year, report that serious injuries related to psychedelics are extremely rare (EMCDDA, 2011; CAM, 2007). Furthermore, Dutch police report that legal sale of psilocybin mushrooms has not led to public order problems (Van Amsterdam et al., 2011). Approximately 0.005% of emergency department visits in the US involve LSD or psilocybin (US Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality 2013; Centers for Disease Control and Prevention (CDC), 2014). Drug abuse experts consistently rank LSD and/or psilocybin mushrooms as much less harmful to the individual user and to society compared to alcohol and other controlled substances (Nutt et al., 2007, 2010; Taylor et al., 2012; van Amsterdam et al., 2010). Controlled studies have not linked either clinical administration or regular use of psychedelics in religious ceremonies to lasting health problems (see Krebs and Johansen, 2013b).
Psychedelics often elicit deeply personally and spiritually meaningful experiences and sustained beneficial effects (Carhart-Harris and Nutt, 2010; Griffiths et al., 2008, 2011; Morgan et al., 2010). Common reasons for using psychedelics include mystical experiences and personal development (Hallock et al., 2005). Indeed, in many countries, including the US, select groups have protection from prosecution on grounds of freedom of belief or religion. People have used psychedelics for at least 5700 years (Bruhn et al., 2002), pre-dating the major organized religions. Modern anti-psychedelic legislation began 100 years ago when members of rival religious groups campaigned against Native American peyote use, calling peyote addictive and an ‘insidious evil’ that causes users to ‘withdraw from the churches and become “peyote worshipers”’ (Newberne and Burke, 1922). Eventually, concerned scientists defended peyote users, using evidence-based reasoning and human rights arguments (Collier, 1952; La Barre et al., 1951; Le Farge, 1960); this led to legal exemptions for specific groups. However, laws and cultural biases against peyote remained in place and were later extended to include other psychedelics. Concerns have been raised that the ban on use of psychedelics is a violation of the human rights to belief and spiritual practice, full development of the personality, and free time and play (United Nations General Assembly, 1948; Walsh, 2014).
There is increasing interest in the therapeutic use of psychedelics, especially for alcoholism (Krebs and Johansen, 2012), smoking cessation (Johnson et al., 2014), depression and other mental health problems (Baumeister et al., 2014; Bogenschutz, 2013; Hendricks et al., 2014). David Nutt and colleagues have explained how national and international regulations have impeded scientific research and medical treatment development with psychedelics and other highly controlled ‘Schedule I’ substances (Nutt et al., 2013). Prohibition has also obviously had negative consequences for the millions of individuals who find it worthwhile to use these substances in various cultural settings outside of the clinic.
Our previous population study failed to find evidence for a link between psychedelic use (lifetime use of LSD, psilocybin, mescaline, or peyote, past year use of LSD) and past year serious psychological distress, receiving or needing mental health treatment, or symptoms of eight psychiatric diagnoses, including major depression, anxiety disorders, mania and psychosis, or visual hallucinations (Krebs and Johansen, 2013b). Here, using a new large data set, which included data on suicidal thoughts and suicide attempt, we again examine the associations between the use of psychedelics and mental health.