Casual Pot Smoking Causes Brain Damage

[liveonearth]

OK, maybe that's a little exaggerated, but basically any drug causes a dopamine surge that changes your brain such that the rewards of normal life don't seem good enough anymore. This study actually found that pot smokers have a bigger nucleus accumbens (the brain area associated with pleasure, reward, and reinforcement learning). They say that 19 million Americans have smoked pot recently. That's a lot.

Here's the article:
http://www.washingtonpost.com/news/morning-mix/wp/2014/04/16/even-casually-smoking-marijuana-can-change-your-brain-study-says/

Even casually smoking marijuana can change your brain, study says
BY TERRENCE MCCOY
April 16 at 3:11 am

The days when people thought only heavy Cheech-and-Chong pot smokers suffered cognitive consequences may be over. 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.”

“This study raises a strong challenge to the idea that casual marijuana use isn’t associated with bad consequences,” he added.

The study analyzed 20 pot smokers and 20 non-pot smokers between 18 and 25. Scientists asked them to estimate how much marijuana they smoked and how often they lit up over a three-month test period. Even those who smoked once a week showed brain abnormalities, while larger changes were seen in those who smoked more.

Marijuana is by far the most recognizable drug in the United States, with almost 19 million people reporting recent use, according to the National Survey on Drug Use. Cultural attitudes toward the drug are changing fast. What would have been inconceivable a generation ago — the decriminalization and legalization of marijuana — has happened in several states over the last several years. Nascent industries around the plant have sprouted in Colorado and Washington since they legalized the drug.
The study did not look at the behavior of the pot smokers, only their brains. What effect, if any, Wednesday’s findings will have on future legislation remains unclear.

The drug’s effect on the human brain, however, is substantially more clear, researchers say. In the study, scientists compared the size, shape and density of the nucleus accumbens and the amygdala, which control emotion. Those who had smoked had abnormally large nucleus accumbens, an area of the brain that controls pleasure, reward, and reinforcement learning.

In the brains of marijuana users, natural rewards are less satisfying.

“Drugs of abuse can cause more dopamine release than natural rewards like food, sex and social interaction,” said lead author Jodi Gilman. “In those you also get a burst of dopamine but not as much as in many drugs of abuse. That is why drugs take on so much salience, and everything else loses its importance.”

*new tag for motivation created today

Comments

[hausfrauatu.livejournal.com]

It's a 40 person study isn't it? 4 times a week is kind of a lot. The assumption that difference is always bad is also specious. People are always going to use intoxicants. They always have. Pot seems the better choice as far as general health compared to other drugs. Nothing is ever going to be perfect.

[liveonearth.livejournal.com]

I agree. Difference is not always bad. Perhaps an enlarged nucleus accumbens makes one more capable of enjoying life. We just don't know. As for which intoxicant is best, pot does seem high on the list for relative harmlessness and enjoyability. Nobody gets away scott free from their choices. It is more harmful to children than is widely appreciated, however, and I agree with measures to keep it out of the hands of minors.

[anais-pf.livejournal.com]

Based on the abstract (since the full article is behind a paywall) it seems as though they didn't study the brains over time . . . just compared pot-smoker's brains to "normal" brains. I wonder if there's any chance that the enlarged nucleus accumbens were pre-existing, and encouraged those people to smoke marijuana more often. In other words, is there any way cause and effect have been reversed?

[liveonearth.livejournal.com]

You are correct, the study does not confirm causality, only association. I had a similar thought, and also the question: what does an enlarged nucleus accumbens mean, functionally?

FYI: I stuck the text of the article behind the "text" cut.

[anais-pf.livejournal.com]

I read the text of the Washington Post article; it's the paywall at The Journal of Neuroscience that stopped me. And yes, I'd be interested in knowing more about the function of the nucleus accumbens in its "normal" and enlarged states.