BDNF and major depressive disorder: In a randomised clinical trial of patients with depression, subjects were randomised to an aerobic exercise plus treatment-as-usual group and treatment-as-usual only group, where treatment as usual included antidepressant treatment and psychotherapy; as a result, a significant increase in serum BDNF was observed in the exercise plus treatment-as-usual group compared with the treatment-as-usual only group (34).