In a study carried out on users of Ecstasy (MDMA as it is known to doctors, and “E†to its consumers), Jonathan Roiser and his colleagues at Cambridge University have shown that someone's risk of developing long-term depression as a result of taking Ecstasy depends critically on his genes.
...
Ecstasy works its magic by affecting the concentration in the brain of a substance called serotonin. ...
Serotonin transporters, however, come in two varieties—the result of there being two versions of the gene that encodes them. These varieties are known as “long†and “shortâ€, and since everyone has two serotonin-transporter genes, one inherited from each parent, a brain may have only long transporters, only short ones, or a mixture of the two....
Dr Roiser and his colleagues invited 66 heavy users—people who had taken the drug at least 30 times—to participate in their study. These volunteers agreed to abstain from their pleasure in the three weeks prior to the tests being carried out, so that the effect of the drug itself, or its immediate aftermath, were not accidentally measured. For comparison, they asked 28 people who had never taken illegal drugs to join in and, for good measure, they had 30 regular cannabis users as well.
Using the depression inventory, the team found that people who employ Ecstasy regularly, and who have two short versions of the gene, are significantly more likely to suffer from mild or serious depression than the others. Importantly, the double-shorted folks who did not use Ecstasy were not more likely to have depression, and neither were double-shorted cannabis users.
