Genetic risk for clinical depression linked to physical symptoms

People with higher genetic risk of clinical depression are more likely to have physical symptoms such as chronic pain, fatigue and migraine, University of Queensland researchers have found.

Dr. Enda Byrne conducted the research at UQ's Institute for Molecular Bioscience, finding that depression was a serious disorder with lifetime risks of poor health.

"A large proportion of people with clinically-diagnosed depression present initially to doctors with physical symptoms that cause distress and can severely impact on people's quality of life," he said.

"Our research aimed to better understand the biological basis of depression and found that assessing a broad range of symptoms was important," Dr. Byrne said.

"Ultimately, our research aimed to better understand the genetic risks and generate more accurate risk scores for use in research and healthcare."

Despite recent breakthroughs, Dr. Byrne said finding additional genetic risk factors was difficult because of the variety of patient ages, their symptoms, responses to treatment and additional mental and physical disorders.

"Previous genetic studies have included participants who report having seen a doctor for worries or tension—but who may not meet the 'official' criteria for a diagnosis of depression," Dr. Byrne said

In collaboration with QIMR Berghofer Medical Research Institute, his team analyzed data from more than 15,000 volunteers who provided details of their mental health history, symptoms of depression and a DNA sample using a saliva kit.

"We wanted to see how genetic risk factors based on clinical definitions of depression differed—from those based on a single question to those based on a doctor's consultation about mental health problems," Dr. Byrne said.

The research found that participants with higher genetic risk for clinical depression are more likely to experience physical symptoms such as chronic pain, fatigue and migraine.

"It is also linked to higher rates of somatic symptoms—that is, physical symptoms that cause distress and can severely impact on people's quality of life," Dr. Byrne said.

"Our results highlight the need for larger studies investigating the broad range of symptoms experienced by people with depression."