Recurrent overdose: patient characteristics, habits, and outcomes

Patients who overdose repeatedly on drugs and poisons (repeaters) are of major concern. This study aimed to examine the demographics, types of drugs ingested, associated self inflicted trauma, and medium term outcome of repeaters and to compare these patients with those who overdosed on one occasion only (single presenters) during the study period.

The study was undertaken in the emergency department of a large, provincial Australian hospital. A retrospective case note examination was made for all patients who presented, after drug overdose, during the two year study period. These patients were also followed up for a further 12 months after the study period.

The study identified 335 single presenters and 46 repeaters. Females formed about two thirds of each group but repeaters tended to be older (p > 0.05) and to present more frequently before midnight (p > 0.05). Significantly more repeat presentations were triaged to the low priority categories 4 or 5 (odds ratio (OR) 0.48; 95% confidence interval (CI) 0.26 to 0.90, p = 0.023) and this group required fewer admissions to the hospital (OR 1.85; 95% CI 1.16 to 2.93, p = 0.009). Repeaters tended to take single drug overdoses. There were significantly more paracetamol only overdoses (OR 0.54; 95% CI 0.32 to 0.92, p = 0.024) and neuroleptic only overdoses (OR 0.27; 95% CI 0.11 to 0.67, p = 0.005) in the repeater group. More repeaters caused self inflicted trauma during the study period (OR 0.20; 95% CI 0.06 to 0.64, p = 0.007). No repeater completed suicide during the study or the 12 month follow up periods but repeaters presented more frequently, after overdose, during follow up (OR 0.38; 95% CI 0.13 to 1.11, p = 0.078).

The study concludes that there are some significant differences between patients who overdose repeatedly and those who overdose on one occasion only. The study findings suggest that the medium term suicidal risk for repeaters is relatively low. However, this risk will vary and individual patients must be assessed thoroughly and managed accordingly.