Dr. Kyla McKay said the study of more than 1,200 patients found no link between anxiety or bipolar disorder and increased disability, however.
She presented the findings at the 7th Joint ECTRIMS-ACTRIMS Meeting in Paris, which started Oct. 25 and runs through Oct. 28.
Psychiatric problems are common in MS. While plenty of research has focused on whether physical illnesses can increase MS patients’ disability, few studies have looked at whether psychiatric conditions can do so.
The Canadian team decided to check for such a link. Their study was titled “Association between psychiatric comorbidity and disability progression of multiple sclerosis.”
They combed through healthcare databases in British Columbia, Canada’s third most populous province, to identify 1,250 MS patients. Three-fourths were women. Ninety-four percent had the relapsing form of MS when diagnosed.
The team used information on physician and hospital visits ranging from two years before a patient’s MS diagnosis to the end of their MS treatment to identify those with depression, anxiety, or bipolar disorder. The average length of treatment was nine years.
It turned out that about half the patients — or 49 percent — had a psychiatric disorder.
Using patients’ scores on an MS disability index, the researchers discovered that patients with a psychiatric disorder had higher levels of disability, even when factors such as sex, socioeconomic status, and additional physical illnesses were taken into account. The disability index they used was the Expanded Disability Status Scale, or EDSS.
The age when a patient developed MS, the progression of the disease, and its duration could not explain the link between the psychiatric conditions and patients’ disability levels, the team said. They also discovered that whether a psychiatric condition was diagnosed before or after an MS diagnosis made no difference in patients’ level of disability.
“Presence of psychiatric comorbidity [disorder] was associated with greater EDSS-related disability,” McKay said.
Interestingly, the link between psychiatric disorders and increased disability held true only for women. Men with any of the three psychiatric conditions did not have higher EDSS scores.
“The link between psychiatric conditions and EDSS may reflect biological factors and psychosocial factors,” McKay said. An example would be smoking.
McKay said the fact that the team found no link between anxiety and bipolar syndrome “could possibly [be due to] the small number of people affected” by those conditions.
The findings indicate that “optimizing management of psychiatric comorbidities should be explored as a means of potentially mitigating disability progression in MS,” the researchers wrote.