By Pat Anson, PNN Editor

Anxiety, depression and other mood disorders have long been associated with fibromyalgia, irritable bowel syndrome (IBS), and chronic fatigue syndrome (CFS). That’s not altogether surprising, since the three chronic illnesses cause body pain, insomnia, fatigue, and other stressful symptoms that can trigger a psychological reaction. No one likes being sick, after all.  

But a large new study found that psychiatric disorders preceded the development of fibromyalgia, IBS and CFS in about a quarter of the people who have the conditions – more than those who suffer from similar chronic illnesses. Anxiety and depression were significantly more common in people who were later diagnosed with chronic fatigue.

"This work provides evidence that for many people, a wide variety of physical and psychological factors are associated with these debilitating conditions," says Francis Creed, a professor emeritus of psychiatry at The University of Manchester.

Creed analyzed over two years of health data from over 120,000 people who participated in the Dutch Lifelines cohort study; comparing the data of people with fibromyalgia, IBS and CFS to those with diabetes, inflammatory bowel disease (IBD) and rheumatoid arthritis. The latter group had similar symptoms and served as a control.

Creed’s findings, recently published in the journals PLOS ONE and Frontiers in Psychiatry, showed that psychiatric disorders were more common (17–27%) in the first group than in the control group (10.4–11.7%).

General anxiety disorder (GAD), panic disorder, dysthymia, major depressive disorder (MDD) and agoraphobia were particularly more common in people who were later diagnosed with CFS.  

Creed says a number of physical and mental health issues may be at work in the development of fibromyalgia, IBS and CFS. He favors a holistic approach to treating them, including a mental health evaluation.   

"When people suffering from CFS/ME, IBS and fibromyalgia come into contact with health professionals, negative attitudes can sometimes get in the way of treatment. but by understanding these complex conditions better, the stigma and mystery around them can be eased," he said.

"Although there are symptomatic treatments which may help these unexplained disorders, we should aim to understand fully their underlying causes. There are probably several different ways they may develop; a whole range of physical and mental factors are probably involved. Treatment approaches will become more effective as our understanding of the causes improves."

Association is not causation, and it’s important to note that about three-quarters of the people who developed fibromyalgia, IBS and CFS did not have any mood disorders prior to the onset of their illnesses.   

Creed says future research and clinical work should focus on possible interactions between psychiatric disorders and other behavioral variables to identify the true role of anxiety and depression in chronic illness.