4. Intentional overdoses and associated mental health challenges, an overlooked sub-population of overdoses

Little is known about the individuals who commit suicide by drug self-poisoning. We aimed to characterize these individuals in comparison to those dying of other types of overdoses.

Utilizing nationwide healthcare registers in Norway, we identified individuals with intentional (ICD10 codes X61; X62; X64) and non-intentional overdoses (F11-16; F19; X11; X12; X14; X41; X42; Y11; Y12; Y14) as causes of death in 2010-2019. We then compared prior psychiatric diagnoses (2008- 2019), prescription drug use before death, and education levels of these groups.

In total, we identified 2656 fatal overdoses, of which 389 (14.6%) were reported as intentional. Compared to the other deceased, intentionally overdosed persons were less frequently men (53.5% vs. 76.2%), older (mean age at death 48.6 vs. 41.5 years) and were dispensed antidepressants, benzodiazepines and related drugs (BZDRs), and opioids more frequently in the last 3 months before death (antidepressants: 35.2% vs. 19.8%; BZDRs: 65.0% vs. 46.8%; opioids: 51.7% vs. 27.3%). Prior diagnoses of depression were more frequent among persons with intentional overdose compared to other overdoses (65.0% vs. 51.5%), as were suicide attempts (28.0% vs. 16.3%) and poisonings with pharmaceuticals (33.4% vs. 24.3%). Substance use disorders, including alcohol abuse, were less frequent (60.9% vs. 85.1%). The intentionally overdosed also had university-level education more frequently than the other deceased (36.4% vs. 25.4%).

Persons who have died of drug overdoses with intentional self-harm differ substantively from persons with other types of fatal overdoses and prevention strategies should be adapted accordingly.