In 2005, we received a 5-year independent investigator grant (R01) from National Institute on Drug Abuse (DA18267), the principal aims of which were to examine the links between age of onset of cannabis use and risks for the subsequent development of other drug use and abuse/dependence. A key goal of the current study was to collect extensive data on patterns of early onset cannabis use and subsequent use and abuse/dependence on other illicit drugs to provide a rigorous test of the gateway hypothesis within a genetically informative research design.
