Adverse psychiatric effects of psychedelic drugs: a systematic review of case reports.

Psychedelic drugs are being studied for treating depression, but concerns about psychiatric side effects persist. A review of case reports found 17 cases of schizophrenia spectrum disorder and 17 of affective disorder (depression, mania, or both) after psychedelic use, excluding people with prior psychiatric illness or other drug use. These conditions could begin after a single use (5 of 17 schizophrenia cases; 6 of 17 affective disorder cases). Recovery was typical for affective disorder but not for schizophrenia spectrum disorder. Among 29 flashback cases, 12 had lasting psychiatric symptoms, mainly anxiety (5 cases) and depression (8 cases). Flashbacks resolved within a year in about half of cases but persisted for years in a few. Serious psychiatric disorders after psychedelic use are uncommon but documented.

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Abstract

Psychedelic drugs are a focus of interest in the treatment of depression and other disorders but there are longstanding concerns about possible adverse psychiatric consequences. Because the relevant literature is largely informal, the seriousness of these risks is difficult to evaluate. Searches were made for case reports of schizophrenia-spectrum, affective or other psychiatric disorders after use of psychedelic drugs. Case reports of flashbacks were also searched for. Individuals with recent use of other drugs (apart from cannabis and alcohol) and/or a previous history of major psychiatric disorder were excluded. Symptoms were tabulated using the Syndrome Check List of the Present State Examination (PSE-9). We found 17 case reports of schizophrenia spectrum disorder, 17 of affective disorder (depression, mania, or both), 3 cases of anxiety, 1 of depersonalization, and 1 of unclassifiable illness. The states could develop after a single use of the drug (5/17 schizophrenia; 6/17 affective disorder), and duration was highly variable. Recovery was the rule in cases of affective disorder but not in schizophrenia spectrum disorder. Twelve of 29 cases of flashbacks showed psychiatric symptomatology definitely outlasting the attacks, mainly anxiety (5 cases) and depression (8 cases). Flashback symptoms resolved within twelve months in approximately half of the cases but in a few persisted for years. Reliable descriptions of schizophrenia spectrum disorder and major affective disorder after psychedelic drug use disorder exist but are relatively uncommon. Flashbacks are sometimes but not always associated with psychiatric symptomatology, mainly anxiety or depression.