Psychoactive substances in natural and unnatural deaths in Norway and Sweden – a study on victims of suicide and accidents compared with natural deaths in psychiatric patients

Background The extent of post-mortem detection of specific psychoactive drugs may differ between countries, and may greatly influence the national death register’s classification of manner and cause of death. The main objective of the present study was to analyse the magnitude and pattern of post-mortem detection of various psychoactive substances by the manner of death (suicide, accidental, undetermined and natural death with a psychiatric diagnosis) in Norway and Sweden. Methods The Cause of Death Registers in Norway and Sweden provided data on 600 deaths in 2008 from each country, of which 200 were registered as suicides, 200 as accidents or undetermined manner of death and 200 as natural deaths in individuals with a diagnosis of mental disorder as the underlying cause of death. We examined death certificates and forensic reports including toxicological analyses. Results The detection of psychoactive substances was commonly reported in suicides (66 and 74% in Norway and Sweden respectively), accidents (85 and 66%), undetermined manner of deaths (80% in the Swedish dataset) and in natural deaths with a psychiatric diagnosis (50 and 53%). Ethanol was the most commonly reported substance in the three manners of death, except from opioids being more common in accidental deaths in the Norwegian dataset. In cases of suicide by poisoning, benzodiazepines and z-drugs were the most common substances in both countries. Heroin or morphine was the most commonly reported substance in cases of accidental death by poisoning in the Norwegian dataset, while other opioids dominated the Swedish dataset. Anti-depressants were found in 22% of the suicide cases in the Norwegian dataset and in 29% of suicide cases in the Swedish dataset. Conclusions Psychoactive substances were detected in 66 and 74% of suicides and in 85 and 66% of accidental deaths in the Norwegian and Swedish datasets, respectively. Apart from a higher detection rate of heroin in deaths by accident in Norway than in Sweden, the pattern of detected psychoactive substances was similar in the two countries. Assessment of a suicidal motive may be hampered by the common use of psychoactive substances in suicide victims.