Suicide and Substance Use Disorder
Article in review: Connery, H.S., Korte, F.M. & McHugh, K. (2020). Suicide and Substance Use Disorder, Psychiatric Annals, DOI: 10.3928/00485713-20200311-01
People who use substances are at an increased risk of death by suicide. The dual epidemics of suicide and substance are described as a “growing health crisis” that contributes to a decrease in life expectancy. These epidemics are not unrelated. This short article provides a summary of the literature related to suicidal thoughts and behaviours in people with substance use and substance use disorders.
The elevated risk of suicide associated with substance use
Suicide risk is elevated amongst people with substance use and substance use disorder and acute substance intoxication are common in people who attempt and die by suicide.
The reasons cited by the authors for this may include:
• The neurobiological effects of acute intoxication effects of substances on disinhibition, impulsivity, aggression and psychosis
• Overlapping social-cultural risk factors associated with substance use and suicide risk
• Complex medical and health risk factors
• The possibility of overlapping genetic determinates in stress response circuitry and neurotransmitter functioning
Despite suggesting that the elevated risk for suicide by people with a substance use disorder is likely to be underestimated, a meta-analysis of studies on the relationship between suicide and substance use found that:
• The acute use of alcohol was associated with a nearly 7 times higher chance of suicide attempt
• High levels of alcohol use was associated with more than 37 time higher chance of suicide attempt
• Alcohol was detected in approximately one third of people who had died by suicide
• Autopsy findings indicated that between 19% and 63% of people who died by suicide had a substance use disorder
• Cohort studies indicated that death by suicide was 10 times more common in people with alcohol use disorder and 13 times more common among people with an opioid disorder
The strength of the association between substance use disorders and suicide varied dependent on a number of factors; including the severity of the substance use disorder and the type of substance used. Alcohol, opioids and sedatives have been strongly linked to increased suicide risk. There are also increased risks when alcohol is used in combination with another substance. Suicidal behaviours is also common among people who use stimulants and despite mixed findings, it appears that chronic cannabis use can be considered a risk factor for suicide as well.
Neurobiological risk factors
Acute substance use may influence cognition and increase suicide risk in a number of ways. Individuals using alcohol and sedative-hypnotics may experience a loss of cognitive control over thoughts of self-harm or injury and may be prone to increased impulsivity. Individuals using stimulants may also experience increased impulsivity or aggression. Opioid users have an increased risk of death by respiratory depression but also experience increased social disconnection. The cognitive capacity of those using hallucinogens may be altered.
Social-cultural risk factors
The link between substance dependency and adverse childhood events has been recognised. It is interesting to note that the strength of the relationship between suicide attempts and adverse childhood events is reduced when adjusting for alcohol and drug use. This suggests that substance use may be a partial mediator.
Other social and cultural factors could be:
• Low education attainment
• rural isolation
• the erosion of social networks
Health risk factors
Possible health risk factors for suicide and substance use amongst those with chronic pain, infectious diseases, substance related injury and experiences of domestic violence, all of which also contribute to social isolation, hopelessness and possible disability which are independent risk factors.
Genetic risk factors
The study of the genetic make-up of people with substance use disorders has identified the presence of common neurotransmitter genes, related to dopamine and the functioning of the stress response. Genetic determinants may provide a further association between suicide and substance use.
Suicide prevention for people with suicide use disorder
The following are suggested as possible strategies for reducing the risk of suicide by people who use substances.
• Health care delivery and screening gaps- including universal screening and prevention interventions in emergency departments, training for health care works and the use of machine learning to analyse data and medical records to identify those at risk
• Medication prevention- the provisions of medications that may have direct pharmacological suicide prevention effects
• Psychosocial prevention- through the delivery of group base prevention initiatives or cognitive behavioural therapies