Richard A. Friedman, New York Times, March 6, 2015
Chances are that everyone on this planet has experienced anxiety, that distinct sense of unease and foreboding.
Most of us probably assume that anxiety always has a psychological trigger.
Yet clinicians have long known that there are plenty of people who experience anxiety in the absence of any danger or stress and haven’t a clue why they feel distressed. Despite years of psychotherapy, many experience little or no relief. It’s as if they suffer from a mental state that has no psychological origin or meaning, a notion that would seem heretical to many therapists, particularly psychoanalysts.
Recent neuroscience research explains why, in part, this may be the case. For the first time, scientists have demonstrated that a genetic variation in the brain makes some people inherently less anxious, and more able to forget fearful and unpleasant experiences. This lucky genetic mutation produces higher levels of anandamide–the so-called bliss molecule and our own natural marijuana–in our brains.
In short, some people are prone to be less anxious simply because they won the genetic sweepstakes and randomly got a genetic mutation that has nothing at all to do with strength of character. About 20 percent of adult Americans have this mutation. Those who do may also be less likely to become addicted to marijuana and, possibly, other drugs–presumably because they don’t need the calming effects that marijuana provides.
We all have anandamide, but those who have won the lucky gene have more of it because they have less of an enzyme called FAAH, which deactivates anandamide. It is a mutation in the FAAH gene that leads to more of the bliss molecule anandamide bathing the brain.
People with the variant FAAH gene are less anxious and are thus less inclined to like marijuana. They actually experience a decrease in happiness when smoking marijuana, compared with those with the normal FAAH gene, who find it pleasurable. If you naturally have more of the real thing you understandably have little use for marijuana.
Studies show that those without the variant gene suffer more severe withdrawal when they stop using cannabis. Here, at last, is an example of a mutation that confers an advantage: lower anxiety and protection against cannabis dependence–and possibly to addiction to some other drugs, too.
Interestingly, the frequency of the advantageous FAAH mutation differs widely among ethnic groups. According to recent data from the HapMap, an international project that studies genetic similarities and differences in humans, roughly 21 percent of Americans of European descent, 14 percent of Han Chinese living in China and 45 percent of Yoruban Nigerians have been found to carry this gene variant.