Do cognitive impairments recover following cessation of cannabis use ?

Our previous research with long term cannabis users established an impaired ability to focus attention and filter out irrelevant information, which was progressive with the cumulative duration of exposure to cannabis. The current study examined these processes in a group of ex-cannabis users. The results suggested a partial recovery of function but the past duration of cannabis use continued to have an adverse effect on the ability to effectively reject complex irrelevant information. There was no indication of improvement with increasing length of abstinence. Whilst relatively subtle in nature, the consequences of such an enduring deficit associated with cannabis use are worthy of further investigation. © 1995.