Depression in multiple sclerosis: a quantitative review of the evidence.

The published literature on depression in multiple sclerosis (MS) is reviewed quantitatively. The authors report mean effect sizes for 20 studies comparing depression scores of MS patients with those of healthy participants (d=1.07) and 21 studies comparing depression scores of MS patients with those of patients who have other chronic conditions (d=-0.14). The confidence interval for the mean overall MS-medical comparison included 0. However, subgroups of patients with chronic fatigue and spinal-neuromuscular conditions were more and less depressed than MS patients, respectively. Results indicate that a majority of MS patients with mild to moderate disability levels are distinguishable from healthy people in terms of depressive symptoms. However, the depression-disease link is complex and not specific to this form of demyelinating illness.