cate that some people who experiment with marijuana may be genetically predisposed to becoming regular users. Whether a person ever tries marijuana, however, appears to be most strongly influenced by one 's family and social environment.
Although marijuana seems to pose an increased risk of abuse for some people, it is generally considered to be only mildly addictive. Compared with users of several other addicting substances, few people who use marijuana become dependent on it (see Figure 3.2). Thus, while many more people try—and use—marijuana than other illicit drugs such as cocaine or heroin, marijuana abuse cases are relatively rare. Two large-scale surveys—the National Comorbidity Survey24 and the Epidemiological Catchment Area Program25—have found that about 5 percent of the U.S. population has been dependent on marijuana at some