Depression, suicide and deliberate self-harm in adolescence.

The past decade has seen important advances in research into the epidemiology, aetiology and treatment of depression and suicidal behaviour in the young. We are beginning to understand how risk factors combine to precipitate and maintain these problems. There is rarely a linear relationship between causes and outcomes. Rather, the cause is usually a combination of predisposing constitutional factors arising from genetic endowment or earlier experience and precipitating stressful events. These aetiological factors act through biochemical, psychological and social processes to produce the outcome. Progress has also been in the development of a range of effective treatments, such as 'here and now' psychological treatments and antidepressants. All depressed or suicidal young people require careful assessment. Some will require a brief intervention only. Others, however, will require more intensive and lengthy forms of treatment.