There continues to be conflicting evidence about the effects of adolescent cannabis use on behavior, neuropsychological functioning, and neurocognitive development. Two new papers on the subject add to the murkiness.
The first paper, which was written by Wendel and colleagues and will be published in Cognitive Development in September 2021, studied the effects of light versus heavy cannabis use on cognitive test performance from age 14 to 19 found no evidence to support the belief that cannabis consumption necessarily leads to a decline in attention, working memory, short-term memory, or risk aversion. In fact, light cannabis users (defined as using cannabis less than 20 times in the previous month) performed better than the control group at follow-up.
The second paper, which was written by Albaugh and colleagues and was published through JAMA Psychiatry online June 16, 2021, was a neuroimaging study that examined the effects of adolescent cannabis use on cortical thickness. They found that cannabis use in mid- to late-adolescence was associated with alterations in cortical development, especially in prefrontal regions where CB1 receptors are highly expressed. They found that the effects were dose dependent.
More research will be needed to determine if there is another factor influencing how cannabis use affects the adolescent brain.