• Depression and multiple sclerosis (MS) can have overlapping symptoms, making it hard for some people to differentiate which condition is prompting their symptoms.
• Data indicates that, among individuals with MS and severe depression, 78 percent also had moderate to severe anxiety.
• Depression has been found to negatively impact cognitive functioning in people with MS.

Depression occurs in about half of all people with multiple sclerosis, and it can affect or worsen cognitive functioning in individuals with the neurological condition. In addition, people with both mental health conditions and MS may find it challenging to differentiate which condition is causing their symptoms, since many of the markers of these diseases overlap. Dr. Sarah Morrow, an associate professor of neurology at the University of Western Ontario, discussed these topics at the Consortium of Multiple Sclerosis Centers (CMSC) Annual Meeting on Oct. 27.

Symptoms like poor concentration, memory issues, and cognitive dysfunction are common in both MS and in depression — and anxiety often accompanies depression, Morrow said. In fact, she noted, 78 percent of people with MS and severe depression also had moderate to severe anxiety.

Studies have indicated that depression can affect or worsen cognitive functioning in people with MS. For instance, depression can impact attention, fatigue, motor function, memory, and information processing speed. These symptoms are also common among individuals with MS. During the CMSC meeting, Morrow noted that it’s possible these symptoms relate to how the body allocates resources to perform tasks.

“The capacity-reduction theory suggests that depression reduces one’s overall capacity to process information,” Morrow noted. “Patients who are depressed allocate more resources to processing negative information, leaving less resources available for other tasks.”

She pointed to the results of a study of people who had MS. Among 69 people in the study who weren’t considered cognitively impaired (based on test results), 51 actually ranked themselves as impaired. The study indicated that mental health conditions such as anxiety and depression could be the reason people were feeling cognitively impaired, even though they weren’t.

Morrow encouraged neurologists to analyze what other factors might be involved when people with MS present with such symptoms as fatigue and cognitive impairment. It’s possible, she noted, that individuals might present with depression and anxiety but won’t necessarily self-identify it.