Marijuana use and its relationship to were investigated in 984 students between the eighth and twelfth grades. Increasing frequency of marijuana use was found to be significantly related to increased creativity, adventuresomeness, internal sensation novelty seeking and impulsivity, and decreased authoritarianism. No differences were noted in manifest anxiety among user groups, but heavier marijuana users earned lower grades in school. Catholics used marijuana the most, Jews were slightly above the mean in usage, and Protestants were lowest. More frequent marijuana use was associated with increased experimentation with other drugs. Multiple-drug users demonstrated increased manifest anxiety and lower grades. College- versus non-college-oriented differences are discussed. The profile of the marijuana user is discussed in terms of an openness to concept, and its value as possibly being predictive of future drug experimentation in present nonusers is mentioned. In recent years, public concern over the increasing incidence of marijuana use has prompted researchers to try and determine if marijuana use is associated with psychopathology. Most results indicate that individuals who are only casually or moderately involved with marijuana do not differ from those who do not use the drug in incidence of psychopathology. It is only when use becomes more frequent or other drugs are involved that differences emerge. In some studies, excessive marijuana use has been found to be significantly related to increased likelihood of involvement with other drugs, poor social and work adjustment, increased hostility, greater difficulty in mastering new problems, and the desire for a psychotomimet ic experience in marijuana use, rather than simple tension reduction or pleasurable stimulation (Keeler, 1968; Mirin, Shapiro, Meyer, Pillard, & Fisher, 1971). Frequent marijuana users and multipledrug users have been found to score significantly more pathological than controls on the Minnesota Multiphasic Personality Inventory (Brill, Crumpton, & Grayson, 1971; McAree, Steffenhagen, & Zheutlin, 1969). Chronic marijuana users have been described as having more personality aberrations, being more