NEUROPSYCHOLOGIC, INTELLECTUAL, AND PERSONALITY CORRELATES OF CHRONIC MARIJUANA USE IN NATIVE COSTA RICANS*

Abstract
The present cross-cultural study investigated the effects of chronic marijuana usage on higher adaptive brain functions and personality in native Costa Ricans. After extensive standardization in Costa Rica, a battery of neuropsychologic, intelligence, and personality tests was administered to two carefully matched groups of marijuana users and controls (NU = NC = 41). Multivariate analyses of multiple combinations of variables, followed by separate univariate tests on each measure, revealed essentially no significant differences between users and nonusers on any of the neuropsychologic, intelligence, or personality tests. Furthermore, no relationship was found between level of daily use (high vs low) and test performance. These findings were discussed in terms of previous chronic and acute studies of changes in adaptive brain functions and personality as a function of marijuana intake.