Change in cannabis use, clinical symptoms and social functioning among patients with first-episode psychosis: a 5-year follow-up study of patients in the OPUS trial

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BACKGROUND: Several studies indicate that cannabis use among patients with psychotic disorders is associated with worse outcome, but only a few studies have controlled for baseline condition and medication.

METHOD: At 5-year follow-up, interviews were carried out with 314 first-episode psychosis patients included in the OPUS trial. The patients included were in the age range of 18 to 45 years old and 59% were male. Cannabis use was extracted from the Schedule for Clinical Assessment in Neuropsychiatry. At follow-up, the patients were divided into different groups according to the variable cannabis use: abstainers, stoppers, starters and continuers. Psychotic, negative and disorganized dimensions (ranging from zero to five) were calculated for each of the four groups based on the Schedule for the Assessment of Positive and Negative Symptoms in Schizophrenia.

RESULTS: Cannabis users were younger (24.6 years v. 27.4 years, p <0.001) (adjusted (ci) (difference -0.31, -1.04, -1.77 0.41-1.53, 0.97, 2.13-14.39, 5-year 8.26, 95% [difference a after and antipsychotic assessment at baseline between cannabis ci confidence controlling difference dimension education. entry even follow-up follow-up, for functioning global had higher in insufficient interval level levels lower medication of on p="0.006).</p" psychotic scores significantly stopped symptoms the those to users using who>

CONCLUSIONS: Continuous cannabis use was associated with higher levels of psychotic symptoms after 5 years, and this association was only partly explained by insufficient antipsychotic medication.

Original languageEnglish
JournalPsychological Medicine
Issue number1
Pages (from-to)117-126
Number of pages10
Publication statusPublished - Jan 2014

    Research areas

  • Adolescent, Adult, Antipsychotic Agents, Cohort Studies, Female, Follow-Up Studies, Humans, Male, Marijuana Smoking, Middle Aged, Psychotic Disorders, Severity of Illness Index, Young Adult

ID: 138423094