Abstract
Sex differences in opportunities to use alcohol or drugs, and transition to use, were investigated in 15 surveys, in 2001-2004 (Europe 6; Americas 3; Africa 2, Asia 3; Oceania 1). The paper focuses on 18-29 year olds (N = 9,873). The World Mental Health Survey Initiative oversaw the surveys; each country obtained its own funding. A complex picture emerged with different results for alcohol and for drugs and for opportunity to use and the transition to use. Sex differences in opportunity to use alcohol were small except in Lebanon and Nigeria, whereas for drugs, the largest differences were in Mexico and Colombia.