This Article  • Full text  • PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Contact me when this article is cited  Related Content  • Similar articles in JAMA  Topic Collections  • Pediatrics  • Adolescent Medicine  • Substance Abuse/ Alcoholism  • Alert me on articles by topic  Social Bookmarking   What's this?

	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

To the Editor: Dr Lynskey and colleagues¹ concluded that early cannabis use is associated with an increased risk for later use and dependence on other drugs. Although the authors used both monozygotic and dizygotic same-sex twins to ensure similar environmental influences, we are concerned that the sample may not be representative of the population, as there was an unusually high prevalence of alcohol dependence in both cannabis users and their co-twin controls compared with that of the general population.^2-3 Early cannabis users in the study of Lynskey et al had a 42.8% prevalence of alcohol dependence, whereas their co-twin controls had a prevalence of 29.6%. By contrast, the prevalence of alcohol abuse among Australian adults has been reported to be about 6.5%,^{2, 4} with a 4.1% prevalence of alcohol dependence.² About 8.3% of Australians aged 14 years and older report daily alcohol use.⁵ Similarly, the prevalence of alcohol dependence in the . . . [Full Text of this Article]

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter     What's this?