The largest study yet into the effects of cannabis on the brains of 18- to 36-year-olds has found that the drug can reduce brain function during cognitive tests. The findings will help people to make an informed decision about the pros and cons of using cannabis.

Cannabis use can significantly impact the part of the brain responsible for following instructions, responding during conversations, or remembering a question long enough to answer it. This type of cognitive function is a form of short-term memory called working memory.