Depression results in disability through decreases in emotional, physical, and cognitive function. Because of a decline in functional reserve in older patients, it is especially important to treat reversible causes of disability. Previous studies have indicated that treatment of depression improves role and emotional functioning but not physical functioning. The Improving Mood: Promoting Access to Collaborative Treatment trial studied the effect of collaborative treatment of depression on physical functioning in older adults.

This multicenter study enrolled 1,801 depressed primary care patients 60 years and older. Patients were randomized to usual care or an educational intervention on depression managed by a depression clinical specialist who collaborated with the patient and his or her regular physician to develop a treatment plan. These patients received a stepped-care plan based on treatment response. All patients received a baseline interview and 12-month follow-up. Outcome measures for physical function were based on the assessment of instrumental activities of daily living (IADLs) and a 12-item scale based on the Short Form Health Survey. Burden of illness and self-rated health also were measured.

The average age of patients in the study was 71 years, with 30 percent reporting impairment of at least one activity of daily living at baseline and 45 percent of participants rating their overall health as fair or poor, indicating a high rate of comorbid conditions. Of the usual care group, 19.3 percent had substantial improvement in depressive symptoms over one year, compared with 44.6 percent of the intervention group. The mean between-group differences in functional status scores were 0.33 at baseline, 1.08 at three months, 1.57 at six months, and 1.71 at one year. Difference in score on IADLs were 0.08, 0.03, –0.06, and –0.15, respectively (indicating no loss of IADLs function in the treatment group).

The authors conclude that collaborative care for depression management improves functional status in older adults better than usual care. Improvement in depression was proportionate with functional status. IADLs functioning was preserved in the intervention group, as opposed to loss of IADLs functioning in the usual care group over one year. These findings suggest that effective treatment of depression can reverse functional status. However, only one half of the patients in the intervention group had resolution of their depression during the study, and the differences between groups, though statistically significant, were small. Over a large population, however, these small differences might have substantial positive public health implications.