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Methamphetamine (MA) dependence and HIV are associated with preferential injury to fronto-striatal-thalamo- cortical circuits and additive deleterious neurocognitive effects. However, their effects on social cognitive processes dependent upon these circuits (e.g., Theory of Mind; ToM) remain unknown. ToM describes the ability to mentalize beliefs and emotions of others in order to respond adaptively. As many HIV transmission risk scenarios are interpersonal, poorer ToM may bias individuals toward increased engagement in risk behaviors. This dissertation project aimed to: 1) examine separate and combined effects of HIV and MA on ToM; 2) evaluate relationships between ToM and risk behaviors; and 3) examine these relationships in the context of decision- making and other executive functions. Thirty-three HIV+/MA +, 32 HIV+/MA-, 31 HIV-/MA+, and 30 HIV-/MA- individuals completed ToM measures (Mind in the Eyes Task, Combined Stories Task, Questionnaire of Cognitive and Affective Empathy; QCAE), a psychiatric interview, self-report risk behavior questionnaires, and a full neuropsychological battery. Jonckheere-Terpstra tests evaluated whether results were consistent with an additive effect on ToM. Regression models were used to test for a moderating effect of decision-making on the relationship between ToM and HIV transmission risk behaviors in HIV+ individuals (independent of other clinical factors and executive functioning performance). Jonckheere-Terpstra tests were significant for Mind in the Eyes performance (healthy individuals outperformed each single-risk group, and dual- risk groups performed most poorly) and approached significance on Combined Stories Task items. Self-reported ToM (QCAE) did not significantly differ. HIV+MA+ individuals engaged in significantly elevated rates of sexual and substance-related risk behaviors. In HIV+ individuals, MA group status was the only significant independent predictor of risk behavior; ToM performance (Eyes RT, Eyes # correct) approached significance. A moderating role of decision-making was not supported by the data. These results held in the context of executive functioning performance. These analyses indicate that HIV infection and methamphetamine dependence are associated with poorer cognitive and affective ToM. Dual-risk groups performed more poorly than single-risk groups on ToM measures, demonstrated poorer decision-making, and engaged in elevated rates of risk behaviors. In HIV+ individuals, MA status robustly predicted risk behavior engagement, although aspects of ToM appear to play a role |
