The chronic cerebral effects of cannabis use. I. Methodological issues and neurological findings.

This paper examines the research evidence relating sustained use of marijuana to chronic cerebral impairment. Evidence from both American and cross-cultural studies is reviewed, with a particular emphasis on methodological problems in the research. The focus of this paper is on neurological findings while another paper focuses on neuropsychological findings. On the basis of available research, it was concluded that there is no evidence that marijuana produces gross structural cerebral changes and little evidence that it leads to functional impairment, although subtle impairment cannot be ruled out.