People with multiple sclerosis who also have depression are more likely to suffer debilitating symptoms early than people with MS who are not depressed, according to a new study. The findings highlight the need for early recognition and treatment of depressive symptoms in patients with MS.

In this study, the researchers at Karolinska Institutet, in Sweden, compared the course of the disease in nearly 1,800 MS patients who were depressed with that of about 7,900 MS patients who were not depressed during a period of up to 13 years. They found that depressed MS patients had an almost 90 percent higher risk of reaching a state where they needed a cane to walk 100 meters than those who were not depressed. This was also the case for those who were diagnosed with depression before their MS onset, which suggests that the MS disease in itself is not necessarily the cause of the depression, according to the researchers.

The observed links may be interpreted in several ways. For example, MS patients with depression are more likely to smoke than nondepressed and are more inclined to neglect taking their medications. Depressed people are also less eager to exercise, and a lack of physical activity could lead to a more rapid deterioration. It is also possible that depression and MS have shared disease mechanisms that enhance each other. In that case, treatment of depression is a particularly important part of MS care. More research is needed to determine the causality between depression and MS worsening.

The study was published in the journal Neurology.