This is the Washington post today:
A study in The Journal of Neuroscience says even casual marijuana smokers showed significant abnormalities in two vital brain regions important in motivation and emotion.
“Some of these people only used marijuana to get high once or twice a week,” said co-author Hans Breiter, quoted in Northwestern University’s Science Newsline. Breiter hailed the study as the first to analyze the effects of light marijuana use. “People think a little recreational use shouldn’t cause a problem, if someone is doing OK with work or school,” he said. “Our data directly says this is not the case.”
Below is the section of The Truth About Drugs documentary on marijuana. Moving stories from former addicts who tell how “casual” marijuana use led to their demise.