Self-poisoning is defined as the intentional self-administration of more than the prescribed dose of any drug, whether or not there is evidence that the act was intended to cause self-harm (Hawton et al, 1997). About 80% of self-harm episodes are self-poisoning (Hawton et al, 2007). Basic medical management of overdose is lent more space here than is usual in a psychiatry text, for the benefit of those practising in isolated circumstances or low-resource communities. In such situations, time might be of the essence and knowledge of simple therapeutic measures and how to avoid pitfalls is essential. In the UK, acute facilities are usually readily available, but this is not invariably the case. Parts of mid-Wales, for example, are over 1 h away from the nearest district general hospital (not allowing for ambulance attendance time).

The role of an attending psychiatrist is to arrange urgent transfer to an appropriate emergency department before competently assessing the patient in the time available and administering basic life support if necessary. Elementary expediencies should not be overlooked: for example, placing an intoxicated patient in the recovery position.

The prevalence of different substances used for self-poisoning recorded at the John Radcliffe Hospital in Oxfordshire is shown in Fig. 19.1. Paracetamol accounts for almost 50% of overdoses (Hawton et al, 2011a). Self-poisoning is more prevalent in women (57%), with two-thirds under 35 years of age. Women aged 15–19 years make up the largest group (Hawton et al, 2007). Self-poisoning decreased in England between 2000 and 2007 (Bergen et al, 2010). Older adults have a high suicide rate, with 1.5% taking their own life within 1 year of a non-fatal self-poisoning (Murphy et al, 2012).

Just 0.6% of paracetamol overdose cases attending emergency departments result in acute liver failure, but overdose can be a portent of further self-harm in young people, with 17.7% of adolescents self-harming a second time withn 1 year of first attendance at hospital with self-poisoning (Hawton et al, 2012a), and 27.3% repeating self-harm after follow-up by up to 7 years (Hawton et al, 2012b).