Preliminary data from the Australian Genetics of Depression Study shows that two-thirds of Australians with clinical depression have used more than one antidepressant to try to manage the condition.

Earlier this year, researchers in Australia launched the largest genome-wide association study (GWAS) into clinical depression in the world so far. Roughly one in seven Australians will suffer from clinical depression during their lifetimes and yet the genetic roots of the disease are still very poorly understood. Currently, treatments are limited to ‘blind’ prescriptions in the hopes that the drug in question will be effective and not cause side effects. The outcomes of these prescriptions will often not be identified for several weeks after the initial dosage and treatment failures are both common and unpredictable, as clinicians cannot identify why the treatment is ineffective.

“In psychiatry, we have really suffered because we’ve been stuck with clinical categories that don’t predict very well the response to treatment,” said Professor Ian Hickie, AM, co-investigator, when speaking with the Australia Associated Press at the time of launch. “Bipolar depression is a great example of that because within that group you have people who do really well with anti-depressants and some people who do hopelessly and only have severe side-effects.”

More than 10,000 adults living with the mental illness have so far enrolled in the Australian Genetics of Depression Study and researchers have released some of the preliminary data that has shown that two-thirds of Australians are with clinical depression have used more than one antidepressant to try to manage the condition.

Lead investigator Nick Martin at the QIMR Berghofer Medical Research Institute says the data highlights that current treatments are far from perfect and that there is room for improvement.

“About 30 per cent of people say that antidepressants work but a large proportion of those have had trouble with them in terms of side-effects so they’ve had to swap prescriptions a number of times to actually find one that works for them,” Professor Martin said.

“In no way is this dissing the profession or the medications that are available at the moment – they are the best we’ve got.”

Professor Ian Hickie says the data confirms what has been frustrating many in the field for a long time.

“We’ve reached the limit of our current knowledge of treating clinical depression,” he said.

“Given our lack of diagnostic methods to predict different responses to antidepressants, or forecast the potential for intolerable side-effects, we are exposing those battling clinical depression, to trial and error, which is often slow to deliver significant benefits.

“To date, we have failed to move effectively from the general principles of treating clinical depression, to much more personalised and targeted approaches that minimise risk to maximise benefit.”

Genetics is the key to fixing this problem, Professor Martin said.

The geneticist is urging more Australians living with the mental illness to enrol in the study that requires a total of 20,000 Australian study volunteers aged 18 and over.

“The link between genetics and clinical depression is very clear. Approximately 20,000 genes make up the human genome,” he said.

“Alterations in some genes cause clinical depression. But right now, we don’t know what they are. What we do know, however, is how to find them.

“We just need a large enough study, performed the right way, to identify them.”

It is hoped the “groundbreaking” research will lead to the identification of between 50 to 100 genes that influence a person’s risks of developing depression.

“Only then, through cracking the genetic code of clinical depression, will we be able to develop new, and more effective, personalised treatments that target the problem directly,” Professor Martin said.

 

 

To volunteer for the study or to find out more, you can visit their website or email the team.