Morgan, Nirvana2021-10-262021-10-262020https://hdl.handle.net/10539/31783A thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, 2020Heroin dependence is associated with significant harms, including comorbid psychopathology, HIV, hepatitis, death by overdose and suicide. Studies from developed countries have measured the effectiveness of different treatment models in heroin users. Data suggests that, even though some heroin users are unable to remain heroin abstinent in the short-term, a significant proportion have successful treatment outcomes. In South Africa, detoxification and an abstinence-based model of care is offered by state sector substance rehabilitation facilities. There are no prospective studies evaluating the outcomes of treatment in heroin users who have accessed these facilities. Here we present the results of a longitudinal cohort study. We measured drug use, psychopathology, injecting and sexual behaviour, social functioning, criminality and general health in 300 heroin users admitted to inpatient rehabilitation facilities. We then repeated these measures three months and nine months after treatment. We also measured the DNA methylation status of heroin users and compared them to a healthy matched control group. Chapter One comprises the literature review and study objectives. Chapter One offers a critical analysis of the current body of research in the field of heroin dependence and treatment outcomes and builds a rational for the objectives of the PhD.enThesis