Self-harm
Self-harm—mainly self-poisoning and self-injury—is an important cause of presentation to health services internationally. The annual incidence worldwide is likely to be in the region of 4 per 1000 adults, with a lifetime prevalence of between 3% and 5% in Western countries. Self-harm is more common in young people and more common in girls than boys. Self-harm has a complex aetiology, with sociodemographic, clinical, environmental, and genetic factors all contributing. It is associated with a greatly increased risk of suicide and death by other causes—1 in 50 people die by suicide in the year after hospital presentation for self-harm. Models of suicidal behaviour may help us to understand how different risk factors link together, but risk scales are unlikely to be useful in practice because of their limited predictive value.