“Depression gene” has potential for great happiness too, says study

Depression is a complicated beast. In some ways, the more enlightened we’ve become, the less confident we’ve been of its complicated causes. Say what you like for the ancient Greek assumption that all medical ailments were due to an imbalance of the four humors, it was certainly a quick and easy diagnosis.

Nowadays we know there are a whole bunch of likely causes and triggers for depression. The size of the hippocampus is one, the patient’s circadian rhythm is another, and of course there are genes inherited from our family line that may make you more susceptible to the black dog than others.

Combine these risk factors with traumatic life experiences, and you’ve been dealt a terrible hand in life. But what if you get by without any serious traumas to trigger depression? Could it be that, despite biological susceptibility, some people make it through?

That’s the finding of a fascinating study from the University of Melbourne, which looked at the SLC6A4 gene (“SERT”) – a transporter of serotonin, the well-known mood-regulating neurotransmitter. There are three types of SERT gene: long-long (l/l), short-long (s/l) and short-short (s/s).

It’s the last of these that is typically associated with depression. But the researchers found something surprising: while s/s patients with unhappy childhoods did indeed show serious symptoms of depression, those not only were those that had a normal childhood not depressed – they were thriving.

The findings came from studying 333 middle-aged Australians, 23% of which had the s/s gene. Of that 23%, those who had endured sexual or physical abuse in childhood were more likely to experience severe depression in later life – but those that didn’t were statistically happier than the rest of the population, even happier than those with the l/l gene.

What this seems to suggest is that these s/s subjects feel the effects of life, both good and bad, more vibrantly. As Dr Chad Bousman, one of the researchers in the study, said: “Our results suggest some people have a genetic makeup that makes them more susceptible to negative environments, but if put in a supportive environment these same people are likely to thrive.”

“You can’t change your genotype or go back and change your childhood, but you can take steps to modify your current environment.”

This raises even more questions, of course, but it should at least give depressives some cause for much-needed cheer. As Dr Bousman points out, “it’s not as clear-cut as telling a person that because they have a risk gene, they’re doomed. This research is showing that’s not the case at all.”

The team is now looking further into “life experience sensitivity” by examining multiple genes, but for the moment, the science of depression remains murky and open to interpretation. Sometimes, don’t you just wish the Greeks had it nailed with their “excessive black bile” treatments?

Images: Delores and Ulisse Albiati used under Creative Commons