Marijuana caused more damage to teens' brains than alcohol, study finds

Joel Shannon  10.6.18
   www.usatoday.com/story/news/nation-now/2018/10/06/marijuana-damaged-teenagers-brains-more-than-alcohol-study-finds/1539574002
   
Marijuana use may pose a greater risk to the developing brains of teenagers than alcohol consumption, according to a new study this week. The analysis, published Wed in the Am J of Psychiatry, found that cannabis had greater short & long-term consequences than alcohol on 4 key components of teens' memory, finding greatly surprised researchers. "We initially suspected alcohol would have a bigger effect," Patricia Conrod, lead author & Prof of Psychiatry at U Montreal told USA TODAY
Researchers looked at 4 cognitive effects: Problem solving, long-term memory, short-term memory manipulation & the ability to stop a habitual behavior when needed. Marijuana had "significant" negative effects on all 4, while the study could not tie alcohol to negative effects, Conrod said. However, alcohol's effects may be greater as teens drink more later in life, Conrod said. Authors examined nearly 4000 students in the Montreal region over 4 years, starting when the average participant was about 13 years old. The students took yearly memory tests & self-reported their alcohol & marijuana use. Those reports were kept confidential "unless such info indicated imminent risk of harm," authors wrote. By the 4th year, 75% of the students had consumed alcohol at least occasionally, while only 30% of subjects had used marijuana. Study observed more daily marijuana users than alcohol users, Conrod said
Study found some of marijuana's negative effects were short-term, while others were lasting. A particularly troubling finding: Young cannabis users may cause long-term damage to a brain function associated with substance abuse. When studying response inhibition —that's an individual's ability to change their actions to help meet a goal —researchers found that teens using marijuana caused long-term damage to their brains. Conrod said that finding may help explain a previously "perplexing" phenomenon: Young cannabis users have been shown to be at a greater risk for addiction later in life.