Psychiatric effects of cannabis use
Acta Psychiatrica Scandinavica September 1, 1985 DOI: 10.1111/j.1600-0447.1985.tb02597.x (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Case series Case report Peer reviewed |
|---|---|
| Sample size | 70 |
| Population | Swedish cases of cannabis psychosis |
| Topics | Cannabis |
| Citations | 84 |
| Key findings | Describes clinical signs in 70 Swedish cases of cannabis psychosis and argues that anxiety reactions, flashbacks, dysphoric reactions, and an abstinence syndrome follow cannabis use, with chronic use producing bluntness and "amotivation." Proposes three risk groups: young teenage users, heavy daily users, and psychiatric patients whose resistance to psychotic relapse may be reduced. |
Abstract
That cannabis use may provoke mental disturbances is well known to Scandinavian psychiatrists today. A review of the psychiatric aspects of cannabis use is given, and the clinical signs of 70 cases of cannabis psychoses collected in Sweden are described. The bluntness and "amotivation" following chronic cannabis use are discussed. Anxiety reactions, flashbacks, dysphoric reactions and an abstinence syndrome are all sequels of cannabis use. Three risk groups begin to emerge: a) Young teenage cannabis users who lose some of their capacity to learn complex functions and who flee from reality to a world of dreams. With its sedative effect, cannabis could modify such emotions as anger and anxiety and slow down the liberation process of adolescence. b) Heavy daily users, often persons who cannot cope with depression or their life circumstances. c) Psychiatric patients whose resistance to relapses into psychotic reactions might be diminished according to the psychotropic effects of cannabis.
Comparable studies
Other case reports and case series on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Psychotic Reactions Following Cannabis Use in East Indians Patients at an Indian drug addiction clinic who developed acute cannabis-related psychosis | 1974 | Descriptive report (case series of clinical observations) | n = 200 |
| Forty-Six Cases of Psychosis in Cannabis Abusers Gunila Bernhardson Habitual cannabis users treated for psychosis at Swedish psychiatric clinics and mental... | 1972 | Case series (retrospective survey of psychiatric records) | n = 46 |
| Hallucinogen persisting perception disorder after psilocybin consumption: a case study 18-year-old man with HPPD after mixed psilocybin and cannabis intoxication | 2005 | Case study | n = 1 |
| Cannabis‐induced Koro in Americans American men aged 22-26 with years of cannabis experience who reported negative... | 2001 | Case series | n = 3 |
| “Hallucinations” Following Acute Cannabis Dosing: A Case Report and Comparison to Other Hallucinogenic Drugs Healthy 30-year-old male | 2018 | Case study | n = 1 |
Citations in the library
Cited by 19
- Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases The British Journal of Psychiatry November 30, 2005
- Drug Induced Psychosis The British Journal of Psychiatry February 1, 1996
- Is there a specific ‘cannabis psychosis’? Cambridge University Press eBooks May 27, 2004
- Is “cannabis psychosis” a distinct category? European Psychiatry 1992
- The Black Book of Psychotropic Dosing and Monitoring Psychopharmacology Bulletin August 12, 2025
and 14 more in the library
Cites 5
- Psychotic Reactions Following Cannabis Use in East Indians Archives of General Psychiatry 1974
- Marihuanann Psychosis JAMA October 13, 1969
- Forty-Six Cases of Psychosis in Cannabis Abusers Gunila Bernhardson International Journal of the Addictions 1972
- Cannabis psychoses in south Sweden. Acta Psychiatrica Scandinavica October 1, 1982
- Psychosis Associated with Cannabis Smoking British Journal of Addiction to Alcohol & Other Drugs September 1, 1972