Repeated self-poisoning: increasing severity of self-harm as a predictor of subsequent suicide

Prediction of suicide risk is difficult in clinical practice.

To identify changes in clinical presentation predictive of suicide in patients treated for repeated episodes of self-poisoning.

A nested case-control study used the Hunter Area Toxicology Service database to identify exposure variables and the National Death Index to identify suicide. Cases were patients who had hospital treatment on more than one occasion between 15 January 1987 and 31 December 2000.

There were 31 cases, for which 93 controls were selected. Study variables associated with an increased risk of subsequent suicide were an increase in the number of drugs ingested (odds ratio 2.59, 95% CI 1.48-4.51), an increase in the dose ingested (OR 1.33, 95% CI 1.01-1.76), an increase in coma score (OR 1.71, 95% CI 1.11-2.66), a decrease in Glasgow Coma Score (OR 1.21, 95% CI 1.03-1.43) and an increase in drug or alcohol misuse (OR 2.33, 95% CI 1.06-5.10).

Patients who have escalating severity of self-poisoning episodes are at high risk of completed suicide.