UCLA

Co-occurring disorder (COD) refers to concurrent psychiatric and substance use disorders (SUD). Compared to those with a single disorder, individuals with COD often require more complex treatment, have poorer health outcomes, and incur higher treatment costs. Researchers have extensively studied both the high lifetime prevalence and age of onset for psychiatric disorders and SUD independently, but little is known about the social antecedents of COD, especially how these antecedents vary by race/ethnicity and gender.

I expect the antecedents do not behave universally, though they are currently treated that way. Guided by the Stress Process Model, the Theory of Fundamental Causes, and the Life Course Perspective, this dissertation aims to better understand the role of childhood poverty and childhood adversity in the occurrence of COD for males and females, and for different racial/ethnic groups. This dissertation employs a secondary analysis of existing community-based survey data recorded in the National Epidemiologic Survey of Alcohol and Related Conditions III.

Using multinomial logistic regression with a four-category variable for disorder (categories: COD, SUD only, psychiatric disorder only, no disorder), on a bivariate level, childhood poverty is associated with COD, however, with the addition of all other covariates there is no longer an association between poverty and COD. Childhood adversities are strongly associated with COD, net of other factors, in all of the models estimated.

There are clear race/ethnicity differences in prevalence of disorder when COD is studied in the whole population. For COD relative to no disorder, Blacks, Asian Americans, and Hispanics, are all approximately half as likely as Whites to have COD, net of other factors. There are no conditional race/ethnicity relationships for COD. There are, however, gender differences in both disorder prevalence and the associations between childhood poverty and COD as well as childhood adversity and COD. Childhood poverty is associated with COD in opposite directions for males and females: for males it increases the relative risk ratio of COD compared to SUD, and for females it decreases the relative risk for this same comparison. This study found no moderation of the childhood poverty and COD relationship by number of adversities in the regressions conducted.

Conducting a survival analysis with only respondents who have at least one disorder indicates that having psychiatric disorder compared to having SUD is associated with a 36% increase in the hazard ratio of subsequently developing COD overall. The significant conditional relationship between disorder sequence and gender shows that hazard of co-occurrence with a psychiatric disorder is higher for males than females. On the contrary, the hazard of co-occurrence when one has SUD is higher for females than it is for males.

This research has clear public health relevance: above and beyond the genetic risk incurred by having a parent with a disorder, experiencing adverse events in childhood is associated with COD. Efforts to help children and adolescents ameliorate the adversity they are exposed to are important and may be able to diminish the risk of COD associated with harmful early experiences.