The Impact of a Registry-Based Environmental Risk Score on Episodes of Alcohol Use Disorder and Drug Use Disorder in Swedish National Samples.

Objective: Psychosocial stress increases the risk for subsequent episodes of alcohol use disorder (AUD) and drug use disorder (DUD), with most studies assessing stress exposure by questionnaire or interview methods. We developed an environmental risk score (ERS) using multiple classes of stressful life events (SLEs) obtained from national Swedish registries.

Method: We assessed, in the entire adult population of Sweden (n = 7,105,712), the occurrence of 51 categories of SLEs derived from registry information for the six months prior to 9/1/2010 and the risk for AUD and DUD registration over the subsequent 18 months. Weights for these two ERSs were obtained from a random half of our sample, and the relationship of ERS to AUD and DUD evaluated in the second half.

Results: The ERS strongly predicted subsequent AUD and DUD episodes. Men were more sensitive to the pathogenic effect of the ERS than women. Those with prior episodes of AUD and DUD had larger absolute increases in ERS-associated AUD and DUD risk than those without previous episodes. Genetic risk for AUD and DUD were associated with greater sensitivity to the pathogenic effects of the ERS. A co-sibling control analysis suggested that a large proportion of the ERS-AUD and ERS-DUD associations were causal.

Conclusions: Valid measures of environmental risks that predispose to AUD and DUD can be assessed from SLEs obtained from high quality national registry data. Importantly, this method avoids prior assessment problems of accurate dating and recall bias and can be performed in large samples.