Frequent marijuana use can negatively affect the brains of teenagers and young adults.

That is according to a group of psychologists discussing public health at the American Psychological Association’s 122nd Annual Convention.

“It needs to be emphasised that regular cannabis use, which we consider once a week, is not safe and may result in addiction and neurocognitive damage, especially in youth,” said Krista Lisdahl, PhD, director of the brain imaging and neuropsychology lab at University of Wisconsin-Milwaukee.....