The most common self-reported factors related to beginning cocaine and heroin use were the desire to experience emotions they believed would accompany the drugs' consumption, the drugs' availability, curiosity about their effects, the desire to fit into a drug-using peer group, misinformation about the drugs' benefits and harms, the desire for energy, and the desire to suppress negative emotions. Because drug use is largely motivated by the desire to suppress negative emotions and stimulate desired emotions, prevention and treatment strategies should focus on the nature and causes of the mental and emotional states from which youth want to escape, as well as constructive means of developing desired emotional states. In the current sample, the alleviation of family-related grief was the most mentioned factor. The provision of information to parents in order to help them develop parenting skills that facilitate caring, attention, and supervision could help youth better manage painful emotions. Youth must also be guided toward positive socializing opportunities and activities with peers. Further, misinformation about the positive benefits of drug use must be challenged with accurate information about the harmful consequences of drug use. This study, called the Young Drug Users in Amsterdam study involved an open cohort of 50 young problem drug users. Eligibility criteria were being 18-30 years old; the use of any form of heroin, cocaine, amphetamine, and/or methadone at least 3 days a week for at least 2 months prior to treatment intake; and Dutch nationality and living in Amsterdam more than 1 year or non-Dutch nationality and living in Amsterdam for more than 3 years. 3 tables and 42 references