Depression increases in some patients with multiple sclerosis over time, according to neuropsychologists, and this research finding could help reduce depression in patients and aid in better treatment strategies.
"Depressed mood in patients with multiple sclerosis changes more significantly over time than other stable depression symptoms such as a negative view of oneself or problems in sleep, fatigue, concentration, and appetite," said Peter Arnett, associate professor of psychology at Penn State.
In addition, data from the tests show that a larger number of patients in the increased depressed mood group were also using interferon beta drugs to slow down progression of the disease, but researchers say it is too early to say whether the drugs might be causing the depression.
"At this point we can only make an inference, but not a causal connection," said Arnett, a faculty member in the College of the Liberal Arts. He published his findings in the current (May) issue of the Journal of Neurology, Neurosurgery and Psychiatry.
Statistical analyses suggest that while symptoms such as negative outlook, sleep problems and concentration remained stable over time, depressed mood changed significantly.
Depression is very common in multiple sclerosis. Around half of all MS patients are diagnosed with clinically significant depression at some time during the course of the disease. This may not only affect patients' cognitive ability but also their daily functions and quality of life, Arnett explained. However, the way in which depression progresses is still unclear because previous studies focused on a single measure of depression, rather than several symptoms such as mood, a negative outlook, and problems with sleep, fatigue, concentration, and appetite.
"We have to understand the characteristics of how depression changes and evolves over time," said Arnett. "A better understanding of the natural history of these changes might help inform better treatment strategies. This is the first study to have done this."
Working with John Randolph of Dartmouth Medical School, Arnett chose 53 patients who were diagnosed with definite or probable multiple sclerosis. Patients were tested twice over a gap of three years to see what effect changes in coping strategies had on the patients' depression, and whether an increase in depression symptoms was linked to interferon beta treatments.