Research discovers potential causes of antidepressant side effects

There is new hope for people who experience side effects from antidepressant medication, with QIMR Berghofer research revealing a person’s genes play an important role in whether they develop headaches, insomnia and weight gain.

The study could lead to more personalised and effective treatment for people with depression.

QIMR Berghofer researcher Adrian Campos said by understanding the side effects better, researchers can work towards preventing them.

“I think we’re nearing a time when doctors will be able to warn patients when they’re at a higher risk of specific side effects, so they better manage them,” Mr Campos said.

“While further research is needed, we were quite surprised to find that antidepressant side effects could be partly influenced by an individual’s genetic makeup. Our findings suggest they can’t be explained by drug exposure alone.”

Mr Campos says they found that people who had tried multiple antidepressants reported the same side effect across the different medications.

“Antidepressant medications are widely prescribed but people often stop treatment over adverse side effects,” he said.

“We wanted to address a lack of research into the issue by investigating the prevalence and risk factors for 23 side effects across ten commonly prescribed antidepressant medications.”

Some of the side effects of antidepressants include reduced sex drive, headaches, insomnia and weight changes.

Lead researcher Miguel Renteria, from QIMR Berghofer’s Department of Genetics and Computational Biology, said they were motivated to take a closer look at potential genetic factors underlying the side effects.

“Our initial findings suggested that there may be common risk factors that made some study participants susceptible to side effects, regardless of which antidepressant they took,” Dr Renteria said.

“We then drew on genetic data from other studies to create risk scores which predict a person’s genetic susceptibility to a specific condition or trait. In this case, we used risk scores for depression, insomnia, weight gain and headaches.

“We found an association between a person’s risk for a trait and their susceptibility to similar or related antidepressant side effects, which suggests these side effects were partly caused by the genes these participants were born with.”

Study co-investigator, Professor Ian Hickie from the University of Sydney’s Brain and Mind Centre said although many people benefit from antidepressant medications, specific side-effects such as weight gain and sexual dysfunction commonly lead people to quit effective treatments.

“Increased understanding of who is most at risk, on the basis of their genetic make-up, is potentially a very important clinical advance. We hope to be able to predict soon who is most at risk, and know this before we commence treatment,” Professor Hickie said.

“That means that we can make appropriate adjustments in the dose or type of medication, thereby giving the greatest chance of delivering real benefits with minimum risk of serious side-effects”. 

The study was published in the journal Communications Medicine, and researchers used data from the Australian Genetics of Depression Study (AGDS).

The study is one of the first major pieces of research produced from the AGDS, the local arm of an international scientific collaboration aiming to better understand clinical depression.

Professor Nick Martin, the lead Australian investigator on the AGDS and the head of QIMR Berghofer’s Genetic Epidemiology Laboratory, said thousands of participants made the ground-breaking research possible.

“The Australian Genetics of Depression Study aims to identify specific genes linked to clinical depression, so we can hopefully develop new and effective treatments for the millions of Australians who will experience this serious condition,” Professor Martin said.

“Australians who have been, or are being treated for clinical depression can still contribute to this important genetic investigation into the illness and its treatment. Volunteering for the study is easy – it all starts with a short survey.”

The AGDS receives funding from the National Health and Medical Research Council. For more information on the AGDS or to volunteer, visit: www.geneticsofdepression.org.au.

If you need support, you can contact Lifeline (13 11 14), Kids Helpline (1800 55 1800), Suicide Call Back Service (1300 659 467), Headspace or Beyond Blue.