Open access. Psychological Medicine; Cambridge Vol. 49, Iss. 8,  (Jun 2019): 1275-1285. DOI:10.1017/S0033291718001757 Background: There is a growing concern about the mental health of children and young people (CYP) in the UK, with increasing demand for counselling services, admissions for self-harm and referrals to mental health services. We investigated whether there have been similar recent trends in selected mental health outcomes among CYP in national health surveys from England, Scotland and Wales.