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- Amstadter, Ananda B., et al.
(author)
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Post-traumatic stress disorder and drug use disorder : examination of aetiological models in a Swedish population-based cohort
- 2023
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In: European Journal of Psychotraumatology. - 2000-8066. ; 14:2
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Journal article (peer-reviewed)abstract
- Background: There are two primary phenotypic models of comorbidity between post-traumatic stress disorder (PTSD) and drug use disorder (DUD), i.e. self-medication (PTSD precedes and causes DUD) and susceptibility (DUD precedes and causes PTSD). We sought to clarify the longitudinal relationship between PTSD and DUD, while examining sex differences. Method: We used approximately 23 years of longitudinal data from Swedish population registries to conduct two complementary statistical models: Cox proportional hazard models (N ≈ 1.5 million) and a cross-lagged panel model (N ≈ 3.8 million). Results: Cox proportional hazards models, adjusting for cohort and socioeconomic status, found strong evidence for the self-medication hypothesis, as PTSD predicted increased risk for DUD among both women [hazard ratio (HR) = 5.34, 95% confidence interval (CI) 5.18, 5.51] and men (HR = 3.65, 95% CI 3.54, 3.77), and moreover, that the PTSD to DUD association was significantly higher among women (interaction term 0.68, 95% CI 0.65, 0.71). The results of the susceptibility model were significant, but not as strong as the self-medication model. DUD predicted risk for PTSD among both women (HR = 2.43, 95% CI 2.38, 2.50) and men (HR = 2.55, 95% CI 2.50, 2.60), and HR was significantly higher in men (interaction term 1.05, 95% CI 1.02, 1.08). Investigating the pathways simultaneously in the cross-lagged model yielded support for both pathways of risk. The cross-paths instantiating the susceptibility model (0.10–0.22 in females, 0.12–0.19 in males) were mostly larger than those capturing the self-medication model (0.01–0.16 in females, 0.04–0.22 in males). Conclusions: We demonstrate that the relationship between PTSD and DUD is bidirectional, with evidence that future research should prioritize examining specific pathways of risk that may differ between men and women.
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| 2. |
- Amstadter, Ananda B., et al.
(author)
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Testing Phenotypic Models of Posttraumatic Stress Disorder and Alcohol Use Disorder Comorbidity Using Longitudinal Registry Data
- 2023
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In: Journal of Studies on Alcohol and Drugs. - : Alcohol Research Documentation, Inc.. - 1937-1888 .- 1938-4114. ; 84:3, s. 378-388
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Journal article (peer-reviewed)abstract
- Objective: Two predominant phenotypic models of causality exist to explain the high co-occurrence of posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD): the self-medication and susceptibility models. Population-based longitudinal studies that simultaneously examine both models are needed. Thus, the goal of the pres-ent study is to test these models using the Swedish National Registries. Method: Registries were used to conduct longitudinal Cox proportional hazard models (n ≈ 1.5 million) and cross-lagged panel models (N ≈ 3.8 million) with follow-up periods of ~23 years. Results: Covarying for cohort and socioeconomic status, Cox proportional hazards model results found strong support for the self-medication model. Results showed that PTSD predicted increased risk for AUD among both men (HR = 4.58 [4.42, 4.74]) and women (HR = 4.14 [3.99, 4.30]), significantly more so for men (interaction HR = 1.11 [1.05, 1.16]). Support was also found for the susceptibility model, although the effects were lower in magnitude than those for the self-medication model. AUD increased risk for PTSD among men (HR = 2.53 [2.47, 2.60]) and women (HR = 2.06 [2.01, 2.12]), and significantly more so for men (interaction term HR = 1.23 [1.18, 1.28]). Cross-lagged model results of simultaneously testing both models found support for bidirectionality. The PTSD-to-AUD paths and the AUD-to-PTSD paths were of modest effect for men and women. Conclusions: The results from both complementary statistical approaches demonstrate that the models of comorbidity are not mutually exclusive. Although the Cox model results evidenced more support for the self-medication pathway, the cross-lagged model results suggest that the prospective relationships between these disorders are nuanced across development. (J. Stud. Alcohol Drugs, 84, 378–388, 2023).
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