The medical debate over pot continues. Long-term use of marijuana causes only minimal permanent damage to neurocognitive functioning. Researchers at the University of California at San Diego (UCSD) found among habitual users, the central nervous system suffered only minor problems of recollection and learning.
The UCSD analysis, published in the Journal of the International Neuropsychological Society, is a synthesis of 15 research studies on the matter. In total, 704 long-term users and 484 non-users were tested for neurocognitive performance including reaction time, attention, motor skills and short-term memory.
Study author Igor Grant, M.D., a professor of psychiatry at UCSD, found little damage in the brain of users. However, users did have selective memory lapses and trouble with learning. He notes that these defects were minor.
While these difficulties could be attributed to alcohol and other drug use, limited information about other drug use by subjects. The researchers were also unable to access how psychological issues, such as depression and personality disorders, factor into marijuana use.