SUPERVISORS DATE SUBMITTED

My sincere gratitude and appreciation is expressed to the following individuals, without whom this research endeavour would not have been made possible:-• Prof. E. Thomson, for her guidance, support and understanding throughout this research project. • Dr. Sanjana Brijball, for her continuous patience, enthusiasm and motivation. • Mr. Zubair Moomal, for his support with the statistical procedures, and other valuable comments. • Ms. Carolene Moonsamy, for her assistance, which is always appreciated. • Mrs. Lee da Rocha-Silva from the Centre for Drug and Alcohol Abuse, for her encouragement and valuable advice over the years. • My parents, Mannie and Naomi, brother Mark and sister Catherine, thank you for your endless support and inspiration, both during this work and over the many years. • To my many other friends and colleagues not mentioned here, my sincere gratitude for your contributions, which have been just as influential an