Substances used in deliberate self-poisoning 1985–1997: trends and associations with age, gender, repetition and suicide intent

Abstract

Background: Rates of deliberate self-poisoning have increased in recent years. While over-the-counter availability and prescribing patterns may influence trends in substances used in overdose, these may also be related to clinical characteristics of patients. We investigate trends in substances used for self-poisoning and the influence of age, gender, suicidal intent and repetition status on the substances used. Method: Data collected by the Oxford Monitoring System for Attempted Suicide were used to review trends and patterns of self-poisoning between 1985 and 1997. Results: There were substantial increases in self-poisoning with paracetamol and antidepressants. While the increase in antidepressant self-poisoning closely paralleled local prescribing figures during 1995–97, SSRI antidepressant overdoses occurred somewhat more often than expected compared with tricyclic overdoses. Paracetamol overdoses were more common in first-timers and young people, whereas overdoses of antidepressants and tranquillizers were more common in repeaters and older people. Self-poisoning with gas and non-ingestible poisons was associated with high suicidal intent. Conclusions: There have been marked changes in the substances used for self-poisoning, which seem primarily to reflect availability, as do the influences of age and repeater status on choice of substances used. Degree of suicidal intent may also influence choice of method of self-poisoning.