Paediatric psychiatry is a branch of medicine that deals with the study and treatment of mental disorders and behaviour of children, from birth through to adolescence. Generally, in the treatment of these disorders the administration of specific drugs for each specific pathology is combined with psychotherapy. Generally, the psychiatrist works with a professional expert in paediatric psychology, which is a branch of psychology focused on the study of behaviour and physical, motor, cognitive, perceptual, emotional and social development of children. Thus, therapies can be applied to solve childhood mental and behavioural disorders.