Combat veterans with Posttraumatic Stress Disorder (PTSD) commonly present with comorbid alcohol misuse. However, factors that contribute to PTSD and alcohol problems, as well as their resolution, remain unclear. Several hypothesised models of PTSD and alcohol misuse comorbidity propose that the tension reduction properties of alcohol have an important functional role in managing PTSD symptoms. By extension, it has also been hypothesised that individuals with PTSD who have tension reduction alcohol expectancies are more likely to misuse alcohol. This latter proposition has not been thoroughly empirically investigated. The purpose of the current body of work is to examine this role of tension reduction expectancies in PTSD and alcohol misuse comorbidity and develop a model of this comorbidity that incorporates expectancy along with other more established constructs.
In Study One, 608 combat veterans diagnosed with PTSD were assessed for PTSD symptoms and alcohol problems prior to group cognitive-behavioural treatment. They were reassessed three and nine months after treatment. Participants were classified into low-risk and hazardous drinkers at each time point. Drinking status at intake did not predict PTSD symptoms at intake or follow-up. However, drinking status was associated with PTSD symptoms when both were assessed at follow-up. PTSD hyperarousal symptoms were the only symptom cluster to differentiate drinking groups. Based on these findings, it was proposed that tension reduction alcohol expectancies and emotional relief drinking refusal self-efficacy may be important in this relationship between PTSD hyperarousal symptoms and alcohol misuse.
In addition to the effects of alcohol refusal self-efficacy, the role of more general coping self-efficacy has not been formally investigated in the development and treatment of problem drinking. In Study Two, 289 alcohol dependent or community participants completed the Coping Self-Efficacy Questionnaire (CSEQ). Principal components analysis produced a 20-item questionnaire composed of three psychometrically sound coping self-efficacy factors: coping with anxiety and depression (CAD), coping with interpersonal challenge (CIC), and coping with frustration and anger (CFA). Consistent with hypotheses, the alcohol dependent sample had lower coping self-efficacy than the community sample. CAD also added variance to the prediction of alcohol consumption beyond alcohol expectancies and drinking refusal self-efficacy, although social pressure and emotional relief drinking refusal self-efficacy were also significant predictors. This study confirmed the importance of both specific and general self-efficacy in alcohol misuse.
Study Three examined psychological factors, including expectancies and self-efficacy, the coping self-efficacy scale produced in Study Two, personality and trauma, associated with cognitive-behavioural treatment outcome for PTSD and alcohol misuse. In 122 male combat veterans, significant predictors of PTSD at intake were alcohol use, combat exposure, psychoticism and coping self-efficacy regarding interpersonal challenges. A broader range of factors predicted alcohol use, including PTSD, alcohol expectancies, drinking refusal self-efficacy, and coping self-efficacy regarding frustration and anger and anxiety and depression. At follow-up, PTSD was predicted by alcohol use and intake psychoticism, while alcohol use was predicted by PTSD, tension reduction alcohol expectancies, subjective dependence, and overall drinking refusal self-efficacy. The results highlight the importance of targeting alcohol misuse in PTSD recovery and support an expectancy tension reduction hypothesis of alcohol misuse in PTSD. Treatment implications are discussed.
In order to explore the kinds of individual differences that may contribute to the role of expectancies in alcohol misuse among veterans with PTSD, Study Four investigated genetic markers associated with both PTSD and alcohol problems in a subset of 45 participants from Study Three. The A1 allele of the Dopamine D2 receptor gene (DRD2) has been found to interact with stress in predicting alcohol misuse. It has also been associated with combat veteran PTSD and drinking at harmful levels and previous research has found that veterans with PTSD who were drinking at harmful levels had a higher frequency of A1 allele than those with low-risk drinking. It was hypothesised that genetic status would predict alcohol use among veterans with PTSD. This hypothesis was not supported by the results. However, participants with PTSD were found to have a higher frequency of the A1 allele of the DRD2 than a previously reported control group. A number of issues regarding sampling and consent are discussed regarding this study.
The Expectancy Tension Reduction Model for PTSD and alcohol misuse comorbidity is presented incorporating social-cognitive theory, trauma variables, personality and genetic status. The implications of this model for prevention and treatment approaches as well as future research are discussed.