Background: The effect of referring patients from a clinical setting to a pragmatic exercise intervention for depressive symptoms, cognitive function, and metabolic variables has yet to be determined.
Methods: Outpatients with major depression (DSM-IV) were allocated to supervised aerobic or stretching exercise groups during a three months period. The primary outcome was the Hamilton depression score (HAM-D(17)). Secondary outcomes were cognitive function, cardiovascular risk markers, and employment related outcomes.
Results: 56 participants were allocated to the aerobic exercise intervention versus 59 participants to the stretching exercise group. Post intervention the mean difference between groups was -0.78 points on the HAM-D(17) (95% CI -3.2 to 1.6; P = .52). At follow-up, the participants in the aerobic exercise group had higher maximal oxygen uptake (mean difference 4.4 l/kg/min; 95% CI 1.7 to 7.0; P = .001) and visuospatial memory on Rey's Complex Figure Test (mean difference 3.2 points; 95% CI 0.9 to 5.5; P = .007) and lower blood glucose levels (mean difference 0.2 mmol/l; 95% CI 0.0 to 0.5; P = .04) and waist circumference (mean difference 2.2 cm; 95% CI 0.3 to 4.1; P = .02) compared with the stretching exercise group.
Conclusions: The results of this trial does not support any antidepressant effect of referring patients with major depression to a three months aerobic exercise program. Due to lower recruitment than anticipated, the trial was terminated prior to reaching the pre-defined sample size of 212 participants; therefore the results should be interpreted in that context. However, the DEMO-II trial does suggest that an exercise program for patients with depression offer positive short-term effects on maximal oxygen uptake, visuospatial memory, fasting glucose levels, and waist circumference.
Trial registration: ClinicalTrials.gov NCT00695552.