Activist Post, July 27, 2011
Investigators at the University of Melbourne and the Australian National University, Center for Mental Health Research assessed the impact of cannabis use on various measures of memory and intelligence in over 2,000 self-identified marijuana consumers and non-users over an eight-year period. Among cannabis consumers, subjects were grouped into the following categories: ‘heavy’ (once a week or more) users, ‘light’ users, ‘former heavy’ users, ‘former light’ users, and ‘always former’ — a category that consisted of respondents who had ceased using marijuana prior to their entry into the study.
Researchers reported: “Only with respect to the immediate recall measure was there evidence of an improved performance associated with sustained abstinence from cannabis, with outcomes similar to those who had never used cannabis at the end point. On the remaining cognitive measures, after controlling for education and other characteristics, there were no significant differences associated with cannabis consumption.”
They concluded, “Therefore, the adverse impacts of cannabis use on cognitive functions either appear to be related to pre-existing factors or are reversible in this community cohort even after potentially extended periods of use.”