Researchers discover hundreds of new genes linked to depression

ABC NEWS (Australia)

An international team of researchers have found hundreds of new genetic variants linked to depression. The study highlights unknown biological factors that underpin the illness.

Transcript

00:00Hi Lono, thank you for having me.

00:04This was a really big international effort in trying to understand the causes of depression.

00:10And so it pulled data from researchers from 29 countries around the world, where we ended

00:15up with a really large sample size, looking at about 680,000 people that had suffered

00:20from depression, and then comparing their DNA to over 4 million people that hadn't had

00:24depression before.

00:25So it's really the world's largest study into the genetics of depression.

00:28Gosh, it is big, and compiling all that data must have caused quite a headache.

00:32What did you find?

00:37We uncovered about 697 small genetic variants, so these are variations in genes that seem

00:44to be associated with risk of depression, and we're really excited about this because

00:47of 300 of these were previously unknown, so it's really increased our understanding of

00:52how biology plays a role in depression risk.

00:55So each thing that you found, on its own, can be a cause of depression, or is it a combination?

01:06It's a combination.

01:07So each of these genetic risk variants have a very small effect on their own, so no one

01:12of them is going to cause depression, but cumulatively they can increase your risk.

01:17But I think it's also important to bear in mind that even if you have a lot of these

01:22genetic variants, that that's not deterministic.

01:24That doesn't mean you will definitely get depression, it just means that you might have

01:28an elevated risk, but obviously things like environment, lifestyle, traumatic experiences,

01:34we know that those also play a really big role in the causes of depression.

01:38So Brittany, what does having this information give us?

01:44How will it benefit how we go from here?

01:50We're really excited about understanding the biology more, because this is really one of

01:55the first steps in providing better treatment.

01:57So if we know what's happening in the brain, and we know what pathways are being enriched

02:01or being activated when people suffer from depression, we can develop drugs that target

02:06these pathways and provide more tailored treatments, or potentially reuse drugs that are already

02:11on the market that are maybe used to treat other disorders, but work on those same pathways

02:17that we now know play a role in depression, and these drugs might then also provide new

02:21treatment avenues for people.

02:22Oh, that's interesting.

02:24So some of the genetic mutations or the genetics that are there can be treated with drugs that

02:30are currently on the market, but just not for depression?

02:33Yes, so that's a really kind of novel and exciting aspect of the study is what we did

02:40was by understanding the genetic variants that are linked to depression and kind of

02:45what biological processes they're involved in in the body, we've been able to map back

02:49to medications that are currently on the market.

02:53So one of the common ones that we highlight in the paper is a medication called modafinil.

02:59It's prescribed to treat narcolepsy and is often prescribed to shift workers that need

03:03to stay up through the night, and we know that that drug targets a lot of the similar

03:09pathways that occur in depression.

03:11So there's potential that this may end up being able to be used for depression.

03:16We're obviously a little way off and we don't want everyone to rush out and buy modafinil

03:22to treat their depression now, but we're very excited by that because it obviously cuts

03:26down the time significantly in getting a new treatment to patients rather than developing

03:33drugs from scratch and having to go through all the clinical trial basis.

03:37We know that it's safe, it's available, it's on the market.

03:40We just don't know if it's going to help with depression, but that's the next step

03:43in the research.

03:44Okay.

03:45We know that with depression, prevention is key.

03:48How does the research that you've been part of, how does it play into that, the prevention

03:54aspect?

03:58I think showing that the biology does play a significant role in depression risk for

04:02some people is really promising, and we've shown that if we create a genetic risk score

04:08from these identified genes that we've found, that this risk score is predictive of depression

04:14and it is able to significantly associate with people that have depression.

04:19And so the ultimate goal would be that this ends up in the healthcare system down the

04:24line and that can then be used with healthcare professionals to match if you know you're

04:30at high risk to help interventions or prevention strategies early on so we can start talking

04:36about preventing depression rather than just treating it once it's occurred.

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