Degree Name

Doctor of Philosophy


Department of Psychology


Substance use in Australia and Iran is a serious threat to the health of young people and the extent of the drug problem is generally underestimated. Financial costs associated with hospitalisation and medical treatment, and social problems such as violence, marital breakdown and delinquency or crime confirm the view that health risk behaviours conducted by young people pose a challenge to Australia's social, environmental and legal systems. Drug education and clinical intervention programs designed to prevent or decrease adolescent drug use need to be based on a clear understanding of the risk factors. Any health risk behaviour stems from positive perceptions of the behaviour. High risk youth who engage in risk taking activities are influenced by normative beliefs and are unduly optimistic about their ability to keep themselves healthy, even though they engage in such behaviours. These youth seem to be oblivious to the risks posed by their behaviour and do not regard such behaviour as creating serious health problems. The present investigation was designed to explore the extent to which the elements of the Integrated Psychosocial Model (IPM) predict substance use in adolescents and young adults in two different cultures. It was also designed to identify to what extent the inclusion of subjective norms would improve the capability of the components derived from the Health Belief Model (HBM) to discriminate between high and low risk youth. This study set out to examine the attitudes and perceptions of high and low risk youth, regarding health risk behaviours such as drinking alcohol, smoking tobacco and using marijuana. At the time this research was planned few cross-cultural studies in this area had been reported using accepted health models. To date, no work of this nature using formal scientific theories has been reported using Iranian subjects. The IPM developed in this research was derived from an analysis of the literature on adolescent health risk behaviours. Theoretical components of the model were extracted from value expectancy theories (specifically the HBM and the Theory of Reasoned Action) which explain behaviour as a function of the subjective value of an outcome and of the subjective probability or expectation that specific performance will achieve that outcome. In line with the literature, and in order to evaluate the effectiveness of the developed integrated psychological model, a self report research instrument was developed and used to obtain data in Wollongong and Tehran. A cross-sectional design was used to test the applicability of the developed model. The research measure included four scales (i) personal information (ii) alcohol use (iii) tobacco smoking and (iv) marijuana use. Four research studies are reported here, examining the robustness and feasibility of the research instrument and assessing the predictive ability of the theoretical components of the IPM.