Co-ingested alcohol and the timing of deliberate self-poisonings

Objective: Investigating diurnal variation in the timing of suicidal behaviours offers opportunity to better understand its various proximal risk factors. Acute use of alcohol is a potent proximal risk factor for suicidal behaviour, though the nature of this risk is poorly understood. The aim of this study was to compare the diurnal variation in time of poison ingestion between deliberate self-poisonings that involve alcohol versus those that do not.Methods: A retrospective analysis of consecutive presentations to a toxicology service following deliberate self-poisoning, 1996-2016. An independent samples Kolmogorov-Smirnov test was performed to test the null hypothesis that the diurnal distribution of poison ingestion time was equal across self-poisonings that did and did not involve alcohol co-ingestion. Presence of circadian rhythmicity was established using cosinor analysis.Results: A total of 11,088 deliberate self-poisoning records, for 7467 patients (60.8% females), were included in the analysis. In all, 31.3% of the total records involved alcohol co-ingestion. Distribution of exposure time was significantly different between deliberate self-poisonings that did and did not involve alcohol (