People who attempted suicide were 1.4 to 1.6 times more likely to develop alcohol, nicotine, or cannabis dependence later, but early substance use showed limited evidence of predicting future suicidal thoughts or attempts.
Read this if you're interested in the directional relationship between cannabis use and suicidal behavior.
Suicide attempts increased odds of later substance dependence by 44-61%
What the researchers found
In a prospective cohort of over 3,200 participants, suicide attempts were associated with significantly increased odds of subsequently developing dependence on alcohol, nicotine, or cannabis (odds ratios 1.44 to 1.61). This held after adjusting for family history of alcohol problems, major depression, and other psychiatric disorders.
Suicidal ideation showed a different pattern: it was associated with reduced odds (0.71 to 0.77) of initiating alcohol, nicotine, or cannabis use. In other words, people with suicidal thoughts were less likely to start using substances.
The reverse direction, whether early substance use predicted later suicidal behavior, showed limited evidence. Several sex and race differences emerged in the associations.
Why it matters
This study challenges the simple assumption that substance use leads to suicidal behavior. Instead, it found that the stronger directional pathway runs from suicide attempts to subsequent substance dependence, suggesting that substances may be used as coping mechanisms after suicidal crises rather than primarily causing them.
The numbers in context
Suicide attempts associated with 1.44-1.61 odds of later alcohol, nicotine, and cannabis dependence. Suicidal ideation associated with 0.71-0.77 odds of initiating substance use. Sample: 3,277 participants from COGA.
How the study worked
Prospective cohort data from the Collaborative Study of the Genetics of Alcoholism (COGA, N=3,277). Cross-sectional and discrete time survival analyses examined bidirectional associations between suicidal ideation/attempts and onset of substance use and dependence across alcohol, nicotine, and cannabis.
What this study cannot tell us
The COGA sample was ascertained for family history of alcoholism, so it may not represent the general population. Not all participants were followed up, creating censored observations. Self-report of suicidal behavior and substance use may be subject to reporting bias. The study cannot establish causation.
How to read the evidence
Prospective cohort study from a large genetics collaboration. The longitudinal design allows examination of temporal sequences, but the sample was enriched for alcohol family history.
When this study was published
Published in 2017. Bidirectional relationships between substance use and suicidality remain actively studied.
The bigger picture
The finding that suicidal crises precede substance dependence more than the reverse has clinical implications. It suggests that suicide prevention could also be substance dependence prevention, and that treating suicidality in isolation without addressing the risk of subsequent self-medication may miss a critical pathway.
Questions still open
- Why does suicidal ideation (without attempt) reduce the likelihood of starting substance use? Are specific substances preferentially used as coping mechanisms after suicidal crises? Would interventions targeting substance use risk after suicide attempts improve outcomes?
Common questions
Does cannabis cause suicidal thoughts?
Why did suicidal ideation reduce substance use initiation?
Read the original research
Reciprocal relationships between substance use and disorders and suicidal ideation and suicide attempts in the Collaborative Study of the Genetics of Alcoholism.
Journal of affective disorders, 213, 96-104
Citation
Agrawal, Arpana; Tillman, Rebecca; Grucza, Richard A; Nelson, Elliot C; McCutcheon, Vivia V; Few, Lauren; Conner, Kenneth R; Lynskey, Michael T; Dick, Danielle M; Edenberg, Howard J; Hesselbrock, Victor M; Kramer, John R; Kuperman, Samuel; Nurnberger, John I; Schuckit, Marc A; Porjesz, Bernice; Bucholz, Kathleen K. (2017). Reciprocal relationships between substance use and disorders and suicidal ideation and suicide attempts in the Collaborative Study of the Genetics of Alcoholism.. Journal of affective disorders, 213, 96-104. https://doi.org/10.1016/j.jad.2016.12.060
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