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Psychological Medicine

ISSN 0033-2917

32 papers in the library · 4,460 citations · publishing 1977-2026

Papers

Cannabis and psychosis: revisiting a nineteenth century study of ‘Indian Hemp and Insanity’ in Colonial British India

Psychological Medicine May 27, 2019 Oyedeji Ayonrinde 11 citations

A historiographic review of the 1892 Indian Hemp Drugs Commission report shows that heavy cannabis use was linked to severe mental illness, accounting for 7.3% of asylum patients and 12.6% of those with diagnoses. About two-thirds were children and young adults, with higher relapse rates. Risk increased with early cannabis use and family history of mental illness. Cannabis psychosis had a shorter trajectory and better prognosis than other mental illnesses. Different cannabis potency and consumption methods had varying effects, while occasional use was considered medicinally beneficial. The report's observations on dose-related effects and psychosis risk in vulnerable young people align with current knowledge.

Ethical issues with psychedelic-assisted treatments in psychiatry: A systematic scoping review

Psychological Medicine January 1, 2025 Chiara Caporuscio, Christopher Poppe, Astrid Gieselmann et al. 9 citations

A scoping review of ethical issues in psychedelic-assisted therapy identifies seven key themes: safety and patient well-being, therapeutic relationships, informed consent, equity and access, research ethics, special contexts, and societal and cultural implications. The review systematically searched multiple databases for peer-reviewed studies on human participants and psychiatric patients, covering publications up to June 2025. The findings aim to inform further discussion and research to support safer and more ethical implementation of psychedelic-assisted treatments as they approach clinical use.

Post-traumatic stress disorder symptoms following psychedelic use: a naturalistic survey study

Psychological Medicine January 1, 2026 Ricarda Evens, Abdo Uyar, Emily Gosslau et al.

About 31% of people who had a distressing psychedelic experience that lasted beyond the acute phase met diagnostic criteria for post-traumatic stress disorder (PTSD). Avoidance during the acute experience predicted worse PTSD symptoms, while acceptance predicted milder symptoms. Post-traumatic growth was unrelated to the intensity of the challenge or avoidance but was linked to acceptance. Most participants sought help from online resources or friends, though psychotherapy was rated most helpful. The study targeted those with highly challenging experiences, so findings do not reflect prevalence among all psychedelic users.

Cannabis use as a potential mediator between childhood adversity and first-episode psychosis: results from the EU-GEI case–control study

Psychological Medicine May 4, 2023 G. Trotta, Victoria Rodriguez, D. Quattrone et al.

Childhood adversity and cannabis use are both known risk factors for psychosis. This study examined whether cannabis use might explain the link between childhood adversity and psychotic disorders. Data from 881 first-episode psychosis patients and 1231 controls from the EU-GEI study showed that household discord was associated with psychosis partly through cannabis use. Lifetime cannabis use mediated 17% of the association, cannabis potency mediated 14%, and frequency of use mediated 29%. Similar results appeared for early exposure to household discord. The findings suggest that harmful cannabis use patterns partially explain how household discord leads to psychosis, and children exposed to challenging home environments could benefit from interventions to prevent cannabis misuse.

Characterizing psychosis-relevant phenomena and cognitive function in a unique population with isolated, chronic and very heavy cannabis exposure

Psychological Medicine October 16, 2019 D. D’souza, S. Ganesh, J. Cortes-Briones et al.

Heavy, chronic cannabis use that begins early and is not accompanied by other drugs is associated with more psychosis-relevant symptoms and poorer cognitive performance. Users averaged over 30,000 lifetime cannabis exposures and scored higher on the Schizotypal Personality Questionnaire (mean 24 vs. 13) and lower on a composite cognitive test (mean -0.23 vs. +0.28) compared to matched non-user controls. Moderate to large deficits appeared in attention, psychomotor speed, working memory, cognitive flexibility, visuo-spatial processing, and verbal memory. A subsample of users also showed worse outcomes than their non-using siblings.

Unpacking the depersonalization syndrome: an exploratory factor analysis on the Cambridge Depersonalization Scale

Psychological Medicine October 1, 2005 Mauricio Sierra, Dawn Baker, Nicholas Medford et al.

Depersonalization symptoms cluster into four distinct but related domains rather than forming a single syndrome. An analysis of responses to the Cambridge Depersonalization Scale from 138 patients diagnosed with depersonalization disorder identified four factors that together account for 73.3% of the variance: anomalous body experience, emotional numbing, anomalous subjective recall, and alienation from surroundings. This suggests that depersonalization is not a unitary condition but comprises separable psychopathological dimensions.