For nearly 6000 years, people have experimented with psychedelic drugs (e.g., LSD, psilocybin, peyote) as a means of enhancing mental and spiritual experiences, and to achieve greater self insight and growth. More than 30 million adults in the United States have reported trying a psychedelic drug at least once in their life time. Psychedelics can have a wide range of psychological effects, including an overwhelming feeling of enlightenment, feelings of euphoria, intense laughter, and vivid visual and auditory hallucinations.
Recently, researchers have shown a renewed interest in the use of psychedelics for the treatment of several mental health problems including depression, alcoholism, and nicotine addiction. However, research on the therapeutic effects of psychedelic drugs has largely been stifled because many governments, despite the existence of strong empirical evidence for their therapeutic efficacy, classify all psychedelic drugs as a scheduled 1 drug. According to National and International laws, psychedelics are controlled substances because of their presumed addictive properties and potential for great harm. These laws have been partly influenced by the misbelief that psychedelics can precipitate mental illness, or even suicide. Recently, some professionals have even claimed that using psychedelics can lead to ‘hallucinogen persisting perceptual disorder’ (HPPD), wherein a person experiences extreme distress related to the experience of recurring hallucinations long after having used a psychedelic drug. Nonetheless, almost all claims regarding the dangers of psychedelic drug use have been largely based on speculation and isolated case studies and should therefore be examined with caution.
A study that was recently published in the Journal of Psychopharmacology by Johansen and Krebs (2015) sought to examine the reported risk of mental health problems that had been presumed to be associated with psychedelic drug use. Using the National Survey on Drug Use and Health, Johansen and Kreb collated data from participants 18 years and older taken from surveys given from 2008-2011. In total the sample consisted of 135,095 respondents and 19,299 of them reported their lifetime psychedelic substance use. Lifetime psychedelic substance use was considered for participants who reported using mescaline or peyote, LSD, or psilocybin at least once throughout their lives. Johansen and Krebs used four different self-reported criteria as indicators of mental health concerns over the previous year: severe psychological distress, access to mental health and addictions treatment, suicidal ideation, and depression or anxiety. In their analysis of those data, they controlled for an extensive number of variables related to socioeconomic status, psychological functioning and drug taking.
Out of 19,299 participants, Johansen and Krebs were unable to link psychedelic drug use to severe psychological distress, access to mental health and addictions treatment, suicidal ideation, or depression and anxiety. Nor did their findings support evidence for the incidence of HPPD, as had previously been reported in case studies. Interestingly, they found that those who reported lifetime psychedelic drug use actually tended to be less likely to have been admitted to psychiatric care over the previous year. In addition, Johansen and Krebs reported that psychedelic drug users were more likely to be younger, white, unmarried males with slightly higher levels of education and income, had personality styles that endorsed risky behaviour and other drug use, and to have experienced a period of depression before 18 years old.
Johansen and Krebs do acknowledge that it is impossible to make causal inferences from a study of this kind. However, the lack of association between mental health problems and psychedelic drug use across a sample of this size does seem to contradict common beliefs regarding their safety. Hopefully, future experimental studies can expand on these findings.
Johansen, P., & Krebs, T. S. (2015). Psychedelics not linked to mental health problems or suicidal behavior: A population study. Journal of Psychopharmacology, 29(3), 270-279. doi:10.1177/0269881114568039