Internalizing disorders refer to problematic or harmful behaviours directed to oneself rather than to others. Although illegal drug use can be considered as an internalizing behaviour, the term is primarily used to refer to sadness, mood disruption, withdrawal, and depression. More serious indicators are thoughts about suicide, and actual attempts at suicide. Eating disorders, including anorexia and bulimia, are another category of internalizing behaviour. ‘Internalizing disorders and adolescent mental health’ considers these issues and explains the risk factors, protective factors, resilience, and possible interventions. There is a characteristic gender imbalance shown in many internalizing disorders in adolescence with females more prone to depression and self-harm.