The first study on the topic of residual effects of cannabis use on neuropsychological functioning was published back in 2011, and it has been followed up by several studies, confirming the high level of evidence for the absence of residual effects of cannabis use on neuropsychological functioning. There are two main arguments for the lack of residual effects of cannabis use on neuropsychological functioning: 1) cannabis use is associated with improved cognitive functioning; 2) cannabis use is associated with improved neuropsychological functioning.
Long-term cannabis use is associated with cognitive impairments that persist after the use of cannabinoids is discontinued. However, these impairments may not be due to residual cannabinoid effects, as the recent literature suggests that residual cannabinoid effects are limited to a few measures of cognitive functioning. In a prospective longitudinal study, we found that cannabis use over 7 years was not associated with changes in measures of neuropsychological functioning.