Abstract
There is growing evidence that early onset substance use increases risk for later mental disorder, however little is known about the beliefs of young people themselves. In 2006, 3,746 Australians (aged 12–25 years) and 2,005 parents were presented with a case vignette portraying psychosis, depression, depression with alcohol misuse, or social phobia. Over 85% agreed that alcohol, tobacco and marijuana were harmful for young people in the vignettes, and that not using substances would reduce the risk of developing such a problem. These findings have important implications for public health campaigns focused on reducing the consequences of adolescent substance use.