Introduction – The population of French Guiana is young, poor, and multicultural. We therefore hypothesized that the epidemiology of mental health problems might be influenced by poverty. The “Mental Health in the General Population” survey estimated the overall prevalence of various mental disorders in the population and in different sociodemographic subgroups using the Mini-Interview.Methods – A cross-sectional survey was conducted between March and August 2021. A total of 881 individuals aged 17 and older were interviewed and included in the analysis.Results – The prevalence of depressive episodes at the time of the survey was 17.1% (95% confidence interval: [14.8–19.8]). For recurrent depression, the prevalence was 7.9 [6.3–9.9]. The prevalence of current depression was significantly higher among young people and those with a monthly income below 840 euros. Therapeutic treatment for depression was also less common among the poorest individuals. This remained significant after adjusting for age and sex. The prevalence of current or past psychosis, suicide risk, and post-traumatic stress disorder appeared to be higher among individuals with a monthly income of less than 840 euros, but the statistical association seemed weaker.Conclusion – The results of this first mental health survey of the general population suggest that, like so many other areas of health, mental health—and in particular depression and its treatment—are impacted by poverty. In this context, as with other health issues, the implementation of proactive, “outreach” approaches—relying on community liaisons and health mediation—makes perfect sense.