Food insecurity has been found to be related to anxiety and depression; however, the association with other psychiatric disorders, particularly among young adults, is not well known. We examined whether food insecurity is independently associated with four common mental health problems among a community sample of young adults in France. Data are from the TEMPO longitudinal cohort study. In 1991, participants' parents provided information on health and family socioeconomic characteristics. In 2011, participants' (18-35years) reported food insecurity, mental health symptoms, and socioeconomic conditions (n=1214). Mental health problems ascertained included major depressive episode, suicidal ideation, attention deficit and hyperactivity disorder, and substance abuse and/or dependence (nicotine, alcohol and cannabis). Cross-sectional associations between food insecurity and mental health problems were tested using modified Poisson regressions, weighted by inverse probability weights (IPW) of exposure. This makes food insecure and not food insecure participants comparable on all characteristics including socioeconomic factors and past mental health problems. 8.5% of young adults were food insecure. In IPW-controlled analyses, food insecurity was associated with increased levels of depression (RR=2.01, 95% CI 1.01-4.02), suicidal ideation (RR=3.23, 95% CI 1.55-6.75) and substance use problems (RR=1.68, 95% CI 1.15-2.46). Food insecurity co-occurs with depression, suicidal ideation and substance use problems in young adulthood. Our findings suggest that reductions in food insecurity during this important life period may help prevent mental health problems. Policies aiming to alleviate food insecurity should also address individuals' psychiatric problems, to prevent a lifelong vicious circle of poor mental health and low socioeconomic attainment.