Anxiety and depression are associated with lower cognitive abilities in patients with multiple sclerosis (MS) other and immune-mediated inflammatory diseases such as inflammatory bowel disease (IBD) and rheumatoid arthritis, a study shows.
These findings indicate the importance of managing symptoms of anxiety and depression in MS, as well as in other inflammatory diseases, to protect brain function.
The study, “Comorbid anxiety, depression, and cognition in multiple sclerosis and other immune-mediated disorders,” was published in the journal Neurology.
According to a press release from the National MS Society, MS patients commonly experience a decline in cognitive abilities, which has a major impact on their quality of life. Furthermore, anxiety and depression have been shown to affect the brain function of MS patients, but results from these studies have been inconsistent.
Similar to MS, patients with immune-mediated inflammatory diseases, such as IBD and rheumatoid arthritis, are also commonly affected by anxiety and depression. However, if and how depression and anxiety affect cognition in immune-mediated inflammatory diseases has not been clearly established.
To investigate a possible link between these health conditions and brain function, a team of researchers from Dalhousie University, Nova Scotia Health Authority, and St. Francis Xavier University in Canada analyzed cognition problems specific to MS and compared them with other immune-mediated inflammatory diseases.
They examined and compared nearly 1,000 participants, mostly Caucasian women in their 40s and 50s. Four diseases were analyzed: MS (255 patients), IBD (247 patients), rheumatoid arthritis (154 patients), and anxiety/depression alone (with no associated inflammatory disorder; 308 patients).
Researchers determined the severity of depression and anxiety in all participants. Additionally, neuropsychological tests were used to broadly assess the core domains of cognitive abilities in the test groups — aptitude for learning and remembering verbal information, working memory capacity, and cognitive processing speed.
Results showed that all four groups tested had higher levels of anxiety and depression than what is seen in the general population.
Anxiety symptoms were linked to reduced cognitive abilities; specifically, slower processing speed, lower working memory performance, and reduced verbal learning. Notably, the influence of anxiety on cognitive function did not differ across the patient groups.
Higher levels of depression were also found to be linked to reduced processing speed.
“Anxiety and depression are associated with lower cognitive function in MS, with a similar pattern observed in persons with other IMID [immune-mediated inflammatory disease], including IBD and [rheumatoid arthritis], and persons without an IMID,” the researchers wrote.
According to them, the findings suggest that “managing symptoms of anxiety and of depression in MS, as well as other IMIDs, is important to mitigate their effect on cognition.”
Further research is nonetheless needed to determine whether successfully treating anxiety and depression can reduce their impact on cognitive function in these patients.