Age-sex differences in medicinal self-poisonings - A population-based study of deliberate intent and medical severity

Background Deliberate self-harm (DSH) is related to suicide and DSH repetition is common. DSH hospital presentations are often self-poisonings with medicinal agents. While older age and male sex are known risk factors for suicide, it is unclear how these factors are related to the nature and severity of medicinal self-poisoning (SP). Such knowledge can guide prevention strategies emphasizing detecting and treating mental illness and controlling access to means. Methods Medicinal SP presentations by 18,383 residents of Ontario, Canada, aged 12 years and older, who presented to a hospital emergency department in that province between April 1, 2001-March 31, 2002 were characterized by the agents taken, identification of deliberate intent and medical severity. Results We found distinct age-sex differences in the nature and severity of medicinal SP. In youths, aged 12-17, about 40% of presentations involved analgesics, typically not prescribed and most often the acetaminophen agent-group. Females aged 12-64 were identified as deliberate more often than their male counterparts and this pattern occurred in most agent-groups, even among those who took antidepressants. The acetaminophen agent-group was most consistently associated with medical severity and this effect was strongest among female youths. Although medicinal SP was less frequent in the elderly, these presentations tended to be more medically serious and less often identified deliberate. Conclusions The high proportion of medicinal SP in youths involving agents typically not prescribed and the medical severity of the acetaminophen agent-group underscore how prevention strategies must extend beyond controlling access to antidepressants. Despite a higher risk for suicide, males and the elderly may not have their deliberate intent detected and therefore, may not receive appropriate treatment. The emergency department can serve as important link to mental health care and usage patterns can provide feedback about the need for system-level enhancements and DSH surveillance.