The American Journal on Addictions, 21: S43–S48, 2012 Copyright C  American Academy of Addiction Psychiatry ISSN: 1055-0496 print / 1521-0391 online DOI: 10.1111/j.1521-0391.2012.00301.x An Expanded Self-Medication Hypothesis Based on Cognitive-Behavioral Determinants for Heroin Abusers in Taiwan: A Cross-Sectional Study Kun-Hua Sam Lee, MS, 1,2 Sarah Bowen, PhD, 3 Tian P. S. Oei, PhD, 4 Cheng-Fang Yen, MD, PhD 5 1 Department of Psychology, Kaohsiung Medical University, Kaohsiung, Taiwan 2 Institute of Allied Health Science, National Cheng Kung University, Tainan, Taiwan 3 Department of Psychology, University of Washington, Seattle, Washington 4 School of Psychology, University of Queensland, Brisbane, Queensland, Australia 5 Department of Psychiatry, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan Background: This study proposed and examined an ex- panded self-medication hypothesis (eSMH) model based on cognitive behavioral determinants, including the direct effects of negative emotional states, positive outcome ex- pectancies and refusal self-efficacy on heroin use, and the mediating roles of positive outcome expectancies and re- fusal self-efficacy between negative emotional states and heroin use. Methods: A total of 360 male heroin abusers were recruited from a drug abuse treatment center in Taiwan. Participants were asked to complete a set of questionnaires on frequency of heroin use, anxious/depressive mood, positive outcome expectancies, and refusal self-efficacy. Structural equation modeling was used to examine the eSMH model. Results: Results showed that the eSMH model displayed proper goodness-of-fit. Positive outcome expectancies and negative emotional status were significant predictors of heroin use, whereas refusal self-efficacy was not a signif- icant predictor. Additionally, positive self-efficacy was a mediator between negative emotional status and heroin use. Conclusion: Results support a reduced eSMH model and suggest a significant role of positive self-efficacy in the re- lationship between negative affective states and heroin use. This relationship should be examined in the longitudinal study, and should be given clinical consideration in treat- ment of individuals struggling with heroin abuse and nega- tive affective states. (Am J Addict 2012;21:S43–S48) INTRODUCTION Heroin use has severe health and financial impacts worldwide. A total of 4.5% of adults reported using heroin Received June 17, 2011; revised July 9, 2011; accepted October 3, 2011. Address correspondence to Mr. Lee, Department of Psychol- ogy, Kaohsiung Medical University, 100, Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan. E-mail: kunhualee627@gmail.com. in the past year in the United States, 1 and the severity of heroin use is highly correlated with psychological distress. 2 Lu, Fang, and Wang indicated a similar climate of heroin use in China. 3 An increased number of heroin abusers were referred to drug abuse treatment, resulting in high annual government costs. 4 Due to the stable prevalence of heroin abuse and the substantial financial and health costs, there is a dire need for continued study of prevention and treat- ment. 5 A comprehensive and reliable psychosocial model of the etiology of heroin abuse is a necessary foundation for both prevention and treatment. However, there is a dearth of literature in this area. Heroin Use and Negative Emotional States Research suggests that individuals with substance use disorders often resume use after a period of abstinence as a means to relieve affective discomfort. 6 Indeed, the effect of negative emotional states (NES) on heroin use has been shown in several studies. 7 For example, in a 33-year follow- up of 242 heroin users, psychological distress and depressive symptoms were a frequent complaint during the recovery period. 8 Hall et al. suggested a prospective epidemiological study or longitudinal neuroimaging study should be con- ducted to clarify the relationship between NES and heroin use. 9 Until now, however, there was a lack of reliable or comprehensive models of a psychosocial model to explain the relationship between heroin use and NES. Self-Medication Hypothesis, Substance Abuse and NES Currently, the self-medication hypothesis (SMH) is a commonly cited explanation of the relationship be- tween NES and heroin use. 10,11 The SMH purports that S43