Rates, characteristics and manner of cannabis-related deaths in Australia 2000-2018

The most commonly used illicit substance worldwide is cannabis. To date, no national level study of cannabis-related death has been undertaken in Australia. The current study aimed to investigate the rates, characteristics and manner of cannabis-related deaths recorded in Australia (2000-2018).

A retrospective case review of medicolegal files was undertaken through the National Coronial Information System (NCIS) (1/07/2000-31/12/2018).

A total of 559 cases were identified, with a mean age of 35.8 years, 81.2% were male. The crude mortality rate per 100,000 people ranged between 0.10 (CI = 0.06-0.15) and 0.23 (CI = 0.17-0.30). The manner of deaths were: accidental injury (29.9%), suicide (25.0%), polysubstance toxicity (17.0%), natural disease (16.1 %), natural disease and drug effect/toxicity (7.9%), assault (3.0%) and unascertained (1.1%). No deaths were solely due to cannabis toxicity. Men were over-represented in this group and were three times as likely to die of accidental injury than women who died from cannabis-related deaths. Motor vehicle accidents were the leading cause of accidental injury. Cardiovascular (14.3%) and respiratory conditions (9.7%) were the most common disease types recorded in cause of death. The median Δ-9-tetrahydrocannabinol blood concentration was 0.008 mg/L (range 0.0005-19.00 mg/L). Other drugs were cited in the cause of death alongside cannabis (81.4%), the most common being alcohol (47.2%).

Low all-cause crude mortality rates remained relatively stable over the study period. No deaths were due to direct cannabis toxicity, but death due to accidental injury was prominent.