Risk of non‐fatal suicide attempt in individuals with substance use disorder: the roles of aggregate genetic liability and environmental exposures in a Swedish population‐based cohort

Abstract

Background and Aims: Substance use disorder (SUD) is related to widespread adverse consequences, including higher suicidality. Shared genetic liability has been demonstrated between SUD and suicidality. Here, we measured the factors that contribute to increased risk of non-fatal suicide attempt among individuals with SUD by focusing upon aggregate genetic risks and both childhood and past-year environmental factors.Design: Longitudinal study. Family genetic risk scores and environmental factors (childhood, aged from 0 to 15 years, and the year preceding SUD registration) were used to predict the relative risk of non-fatal suicide attempt using Cox proportional hazards models. Additional analyses employed a co-relative design, accounting for genetic factors and shared familial environment, to test for potential causality.Setting and participants: Based on longitudinal Swedish registry data, 228 617 individuals with SUD registrations from 1991 to 2015 were included.Measurements: SUD and suicide attempts were identified using medical records (International Classification of Diseases codes). SUD was also identified using pharmacy and criminal registries.Findings: In multivariable analyses that jointly accounted for all the selected potential predictors, individuals with SUD were at higher risk for non-fatal suicide attempt if they had experienced a parental death [hazard ratio (HR) = 1.58; 95% confidence interval (

Risk of suicidal behavior as a function of alcohol use disorder typologies: A Swedish population‐based study

“…Results reveal the roles of family disruption (e.g. having lived in a non-intact family before age 15 years) and low educational attainment, as well as genetic liability for both AUD and suicide attempt [ 10 ].…”

“…Some of the factors associated with suicide attempt within individuals with substance use disorders (e.g. family disruption and low education) [ 10 ] seem to characterize the subgroup with AUD and externalizing disorders. Therefore, examining whether this group would be more at risk of engaging in suicidal behavior is of interest.…”

“…Then, we focused upon each of the three subtypes of AUD (externalizing disorders, minimal psychopathology and internalizing disorders) and compared their risks of non-fatal suicide attempt and suicide death. Finally, we investigated whether distinct risks of suicide attempt and death across AUD typologies were related to specific confounding factors such as AUD characteristics (age of onset and number of registrations), family status, education or genetic risks, as these were identified as good external validators between AUD typologies [ 18 ] and risk factors that explained suicide attempt among individuals with substance use disorders [ 10 ] and suicide death [ 20 ]. We also accounted for suicide attempt prior to AUD, as this is a strong predictor of further attempts and death [ 21 , 22 ].…”

Commentary on Lannoy et al.: The continued value of within‐family designs in addiction and psychiatric research

“…In this issue of Addiction, Lannoy et al [6] The involvement of SES in the relationships between genetic liability for SUDs and psychiatric traits is an important question [7][8][9], with recent studies finding significant changes in heritability [8] and patterns of genetic correlations [7] after accounting for SES. The findings from Lannoy et al add another piece to this puzzle.…”

“…In this issue of Addiction , Lannoy et al [6] employ a clever co‐relative design to investigate potential causal effects on risk for suicide attempt in individuals with SUD. They leverage the fact that their large sample ( n = 228 617) from the Swedish population registries, while not a family‐based sample per se , includes closely related individuals.…”