Matthew carries out mental health services research with young people in two main areas. Firstly, he investigates the interface between physical and mental health. Recent studies include investigation of maternal and child anxiety associated with child food allergy. Secondly, he investigates sociocultural influences on child and adolescent mental health and service contact. He has studied risk and protective factors for psychopathology, and service use amongst young refugees. He also investigates social factors in adolescent psychosis.