Association of depression, anxiety, and obsessive-compulsive disorder with substance misuse : examining the underlying mechanisms with epidemiological methods

Tutkimustuotos: OpinnäyteVäitöskirjaArtikkelikokoelma


Internalizing disorders such as depression, anxiety disorders, and obsessive-compulsive disorder (OCD) frequently co-occur with substance use disorders (SUDs). Causes for the comorbidity remain unclear, and could be explained by several, not mutually exclusive general mechanisms. For instance, shared genetic and/or environmental factors may increase the risk of both internalizing disorders and SUDs, or the risk of SUDs might be causally increased by internalizing disorders via self-medication. The overarching aim of this dissertation was to describe the association of these internalizing disorders with substance misuse during the lifetime as well as during the important developmental period from childhood to early adulthood, and to clarify the mechanisms underlying the comorbidity using quasi-experimental research designs. Sub-studies of this dissertation included two sources of data: Swedish nationwide registers and the Child and Adolescent Twin Study in Sweden (CATSS), a longitudinal twin cohort study. Population-based samples linked to nationwide registers were used in Studies I (n=2,996,398), II (n=1,768,516), III (n=6,304,188), and IV (n=146,114). CATSS data were utilized in Studies II (n=12,408) and III (n=9,230). To account for familial effects, we used stratified analyses within sibling and twin pairs (Studies I and II), and conducted a within-individual analysis (Study IV). We also estimated the contribution of shared genetic and environmental factors to the associations with quantitative genetic structural equation modeling (Studies I and III). Both lifetime and childhood-onset anxiety and depressive disorders were associated with a substantially elevated risk of SUDs and substance use-related criminal offenses. OCD was also associated with an elevated risk of substance misuse, and self-reported OCD symptoms at age 18 were associated with increased alcohol and drug dependence symptoms among people who used alcohol or drugs. Shared familial liabilities contributed to the associations, but the associations were not entirely explained by familial factors. Further, we found an elevated risk of acute intoxications, accidental poisonings by alcohol or drugs, and substance use-related criminal offenses in patients with anxiety and depressive disorders during a 1-month period preceding SSRI medication treatment initiation, when compared to the reference period of more than 1 month before treatment start. On-treatment estimates were consistently lower than the 1 month pre-treatment estimate, but still elevated compared to the reference period. In conclusion, depression, anxiety, and OCD are important correlates of substance misuse across development. Genetic factors play a major role in explaining comorbidity, but the associations were not entirely explained by familial confounding. This pattern of results suggests that the relationship between internalizing disorders and substance misuse partially reflects shared etiology, but the findings were also consistent with (partially) direct effects between the disorders as proposed by the self-medication hypothesis. Thus, it appears that the comorbidity of internalizing disorders and substance misuse arises via several, not mutually exclusive mechanisms.
  • Latvala, Antti, Valvoja
  • Suvisaari, Jaana, Valvoja, Ulkoinen henkilö
Myöntöpäivämäärä5 marrask. 2021
Painoksen ISBN978-951-51-7599-1
TilaJulkaistu - 2021
OKM-julkaisutyyppiG5 Tohtorinväitöskirja (artikkeli)


M1 - 99 s. + liitteet


  • 515 Psykologia

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