What could be responsible for this girl’s change in behaviour?

Jo steer
Clinical Psychologist, Achieving for Children Child and Adolescent Mental Health Service (CAMHS)

Dr Jo Steer reviews a clinical case of a young girl who presents to the GP with her mum. Her friends and family have noticed she is isolating herself and at school teachers say she is often late and has difficulties with attention and concentration. What consultations and tests should be done? What is the likely diagnosis and best management for her?