Discovery of genes that cause clinical depression could help ease GP medication concerns

The discovery of the genes that cause clinical depression could help GPs and other healthcare professionals to more accurately prescribe medication as a result of individual genetic profiling.

The use of antidepressants to treat clinical depression tends to be a complex process riddled with guesswork.

Our own interim data from the Australian Genetics of Depression Study revealed more than two-thirds of Australian study participants have had to rely upon multiple antidepressants to treat their clinical depression.

GPs clearly face a challenging process due to the lack of tools they have to accurately prescribe the most appropriate medications to individuals living with clinical depression. Professor John W.G. Tiller, Professor Emeritus of Psychiatry, The University of Melbourne, recently discussed the issue in a peer reviewed article for the November 2017 Medicine Today issue.

Prof Tiller says antidepressants are not a “one-size-fits-all solution”, and ideally should be used together with psychotherapy and social rehabilitation. Often, a GP will have to withdraw a patient from medication, or switch them to something else. Should they choose to switch or withdraw a patient from antidepressants, there are a number of factors that must be considered, including:

• Adverse effects and whether or not they are transient or related to excessive dosing or drug interactions;
• Dosage;
• Duration of use;
• Whether the diagnosis is correct; and
• Whether the patient has responded well to treatment.

The difficult decision making process of which antidepressant to use for which patient varies significantly from one patient to the next, according to Prof Tiller.

“In general, there is no investigation that can particularly help with optimising antidepressant treatment. Genetic studies of hepatic metabolism of antidepressants have been available for some years, but have had limited clinical uptake.”

By testing the DNA of thousands of Australians, The Australian Genetics of Depression Study is hoping to isolate the genes that influence a person’s risk of developing clinical depression. This could also assist with individual genetic profiling before medication is prescribed.

According to Professor Ian Hickie AM, Australian Genetics of Depression Study Co-Investigator and Co-Director for Health and Policy, Brain and Mind Centre, The University of Sydney, the study could drive a breakthrough in how GPs and other healthcare professionals prescribe antidepressants.

“Our interim data reveals better targeting of existing treatments through individual genetic profiling before commencing medication, would drive a major advance in clinical therapy.

“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,” said Prof Hickie.

If you, or someone you know, has been diagnosed with clinical depression and wishes to volunteer for our groundbreaking genetics of depression study, head here: www.geneticsofdepression.org.au/