Child and adolescent psychiatry is a broad discipline relevant to any health professional who has regular contact with young people. Childhood emotional, behavioural, and developmental problems are common, especially in children with other medical or social difficulties. This chapter aims to provide an approach to child mental health difficulties, while Chapter 32 deals with common and/ or important psychiatric disorders that are specific to childhood. You may find it helpful to revise some basic child development— this can be found in any general paediatrics text (see ‘Further reading’). An overview of the differences between child and adult psychiatry is shown in Box 17.1. As in adult psychiatry, diagnosis of psychiatric disorders often relies on the clinician being able to recognize variants of and the limits of normal behaviour and emotions. In children, problems should be classified as either a delay in, or a deviation from, the usual pattern of development. Sometimes problems are due to an excess of what is an inherently normal characteristic in young people (e.g. anger in oppositional defiance disorder), rather than a new phenomenon (e.g. hallucinations or self- harm) as is frequently seen in adults. There are four types of symptoms that typically present to child and adolescent psychiatry services: … 1 Emotional symptoms: anxiety, fears, obsessions, mood, sleep, appetite, somatization. 2 Behavioural disorders: defiant behaviour, aggression, antisocial behaviour, eating disorders. 3 Developmental delays: motor, speech, play, attention, bladder/ bowels, reading, writing and maths. 4 Relationship difficulties with other children or adults…. There will also be other presenting complaints which fit the usual presentation of an adult disorder (e.g. mania, psychosis), and these are classified as they would be in an adult. Occasionally, there will also be a situation where the child is healthy, but the problem is either a parental illness, or abuse of the child by an adult. Learning disorders are covered in Chapter 19. Table 17.1 outlines specific psychiatric conditions diagnosed at less than 18 years, and Box 17.2 lists general psychiatric conditions that are also commonly found in children.