Changing Epidemiology of Intentional Antidepressant Drug Overdose in Victoria, Australia

Abstract

Aim: To determine the epidemiology of intentional antidepressant drug overdose (OD), over an extended time period, in Victoria, Australia. Methods: Retrospective epidemiological study of all cases reported to the Victorian Emergency Minimum Dataset (VEMD) January 1998 to December 2007 and calls to the Victorian Poisons Information Centre (VPIC) June 2005 to September 2008. Results: 5467 VEMD cases were analysed. 3169 (57.9%) cases involved selective serotonin reuptake inhibitors (SSRIs) and 1149 (21%) involved tricyclic antidepressants (TCAs). Sertraline (1252, 22.9% cases) was the most common drug. During 2001, the peak year of OD, there were 8.8 OD/100 000 population in the SSRI group and 3.8 OD/100 000 population in the TCA group. Trends over the study period showed increasing SSRI and ‘other’ newer antidepressant prescription rates and decreases for TCA and monoamine oxidase inhibitors (MAOI). However, the risks of OD in all drug classes were similar and OD/100 000 prescriptions trended downwards for all drug classes over time. 1833 VPIC calls were analysed. Calls relating to SSRIs were the most common yet SSRI OD was associated with significantly fewer symptoms (p < 0.001) and fewer patients with Poisoning Severity Score classifications of moderate or severe (p < 0.01). Conclusions: Antidepressant OD patterns are changing. Antidepressant OD incidence is following prescribing trends. The risk of OD is similar for all drug classes. Absolute numbers of OD and OD/100 000 prescriptions are decreasing for all drug classes.