In this project, we will investigate social and genetic influences that place adolescents at increased risk of depression, self-harm, obsessive compulsive disorder (OCD), and eating disorders. The influences we will examine will include depression, anxiety and eating disorders in parents, adolescents' sexual orientation, their level of antisocial behaviour, infant colic and excessive crying, and the desire of adolescent boys to be muscular. We will also examine whether genetic influences on schizophrenia are also a risk factor for eating disorders.