Substance Use in Patients With First-Episode Psychosis: Is Gender Relevant?

OBJECTIVE: Only a few studies in patients with first-episode psychosis have included gender in the study hypothesis or considered this a primary study variable. The aim of this study was to explore the influence of gender in the pattern of substance use in patients with first-episode psychosis. METHODS: This is a sub-analysis of a randomized open clinical trial that compared 1-year treatment retention rates of patients with first-episode psychosis randomized to haloperidol, olanzapine, quetiapine, risperidone, or ziprasidone. Our sub-analysis included 85 men and 29 women. RESULTS: Substance use was relatively high among these patients and differed significantly by gender. Men were more likely to use substances overall than women (89.4% for men vs. 55.2% for women), χ(2) = 16.2, df = 1, p <.001, and were also more likely to use alcohol (χ(2) = 13, df = 1, p <.001), cannabis (χ(2) = 9.9; df = 1, p <.002), and cocaine (χ(2) = 10.3; df = 1, p <.001), compared to women. While there were no gender differences in age at first consumption of alcohol or cocaine, men were significantly younger at first consumption of cannabis (M = 16.08 years, SD = 2.1) than women (M = 18.0 years, SD = 3.8), F(1, 59) = 5, p <.02. When analyzed separately by gender, women showed no significant differences in the influence of number of substances used on age at onset of psychosis, F(3, 29) = 1.2, p =.30. However, there was a significant difference among men, with earlier onset of psychosis noted in men consuming multiple substances; F(4, 85) = 5.8, p <.0001. Regarding prediction of age at onset of psychosis, both male gender and the use of a higher number of substances significantly predicted an earlier age at onset of psychosis. CONCLUSIONS: Our study provides some evidence of gender differences in the pattern of substance use in patients with first-episode psychosis, suggesting the possible need for gender-specific approaches in the interventions performed in these patients. This study is registered as #12610000954022 with the Australian New Zealand Clinical Trials Registry (www.anzctr.org.au).