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Abstract
Child maltreatment is associated with increased liability for a range of mental disorders. Some researchers have argued that child maltreatment is a non-specific risk factor for mental disorder, whereas others have suggested particular types of maltreatment are associated with particular mental disorders. The present thesis examines the relationship between child maltreatment and comorbid mental disorder among an opioid-dependent sample and a comparison group with similar social disadvantage. The thesis extends previous research by examining four types of child maltreatment concurrently, controlling for exposure to other family adversity and other drug dependence, and accounting for the comorbidity among the three mental disorders studied: posttraumatic stress disorder (PTSD), major depressive episode (MDE), and alcohol dependence (AD).
The thesis comprises three empirical studies: 1) an initial examination of the measurement structure of child maltreatment and other family adversity; 2) a test of the association between child maltreatment and opioid dependence accounting for other family adversity and other drug dependence; and 2) a series of studies examining the association of child maltreatment with three mental disorders – PTSD, MDE and AD – and testing potential differences between participants with and without opioid dependence. The sample comprised 1394 opioid-dependent participants (61% male) and 384 non-opioid-dependent participants (lifetime opioid use less than five times) (47% male). Data was collected by way of a face-to-face structured clinical interview and analysed using structural equation modeling (SEM).
All four types of child maltreatment were found to be significantly associated with lifetime opioid dependence. The types of maltreatment significantly associated with AD, however, differed for participants with and without opioid dependence, indicating the mechanism by which child maltreatment confers vulnerability for substance dependence differs for alcohol versus other drugs. Opioid-dependent and non-opioid-dependent participants were similar regarding the maltreatment types associated with PTSD and MDE: sexual abuse and physical abuse were correlated with both disorders while emotional abuse was strongly associated with MDE only. Findings are discussed in relation to an internalising-externalising framework of comorbidity, epigenetic influences and cognitive vulnerability for mental disorder, and the need for a trauma-focused drug treatment system.