Previous research has established the effects of maternal mental health on children and adolescents MH but there is limited evidence on the association between maternal mental health and risky behaviours in adolescence, such as substance use (Campbell et al., 2009; Pearson et al., 2013). Studies have demonstrated that depressed parents played a significant part in offspring’s MH and substance use in adolescence and adulthood (Weissman et al., 2006). These results have been replicated by Flouri and Ioakeimidi (2008) finding that adolescents, particularly male, engaged in more risky behaviours, including alcohol use, when their mothers had chronically high or increased depressive symptoms, compared to those that their mothers never experienced depression. Wickham and colleagues (2015) also showed that adolescents who were exposed to maternal depressive symptoms in middle childhood showed a stronger association with using common substances (alcohol, cigarettes, and marijuana) and earlier engagement in such behaviours, including hallucinogenic use. This project aims to extend the evidence and look at different maternal mental health conditions and their relationship with substance use in adolescence using the ALSPAC data.