Dr. Phyllis Ellickson, of the Rand Corporation's Drug Policy Research Center, and her colleagues analyzed survey data from 5,833 California and Oregon middle school students. The participants completed surveys six times over a 10-year period between the ages of 13 and 23. Later, 44 percent of them responded to survey questions at age 29.
Of the 5,833 participants, 3,185 identified themselves as marijuana users, while 2,648 reported they did not use marijuana. The scientists divided the marijuana smokers into four groups, based on the age at which they began using and their subsequent level of use.
Pot Smokers Have Lower IncomesCompared responses from the marijuana users at age 29 with data from age-matched abstainers, researchers found that abstainers had an overall higher level of educational attainment, better health, greater life satisfaction, and a lower rate of other drug use.
In contrast, those who had reported a relatively high level of marijuana use at age 13 fared significantly worse than all other groups on overall health and yearly earnings.
People underestimate the harm marijuana can cause on many aspects of their lives, the study authors said.
Source: The study was published in the May 2004 issue of Health Psychology.