科学美国人60秒:Marijuana Muddies Memory and Mixes with Alcohol to Make Trouble

Marijuana is the drug of choice for people who drink alcohol. And people who use both are twice as likely to do so at the same time than to indulge in just one or the other. That’s according to a study in the journal Alcoholism: Clinical and Experimental Research. [Meenakshi S. Subbaraman and William C. Kerr, Simultaneous Versus Concurrent Use of Alcohol and Cannabis in the National Alcohol Survey

The data came from self-reported answers that more than 8,600 people provided to what’s called the National Alcohol Surveys, done by phone in 2005 and 2010.

People who used pot and alcohol were about twice as likely to drive drunk than those who just drank. And they doubled their chances of what are referred to as negative social consequences, such as arrests, fights and job problems.  

Meanwhile, another new study finds that if you’re chronically stoned, you’re more likely to remember things differently from how they happened, or not at all.  

Researchers showed a series of words to people who do not use marijuana and to regular pot users who had not partaken in a month. A few minutes later, all participants were shown the same list of words along with other words. The volunteers were then asked to identify only the original words. The pot smokers thought more of the new words were in the original list than did the nonusers. And brain scans revealed that the regular pot users showed less activity in brain regions associated with memory and cognitive resources than did the nonusers. The study is in the journal Molecular Psychiatry. [J. Riba et al, Telling true from false: cannabis users show increased susceptibility to false memories]

Marijuana use is much more acceptable than it used to be, both socially and legally. But these two studies show that pot, especially when mixed with alcohol, can affect the brain in negative ways, both immediately and in the long run.

—Erika Beras