The Canadian Journal of Diagnosis / November 2004 35 Complementary Medicine

evidence-based review of alternative therapies Depression is one of the mostcommon problems treated inclinical practice. Even though drug therapy and psychothera-py are effective at alleviating symptoms, many cases of depression remain undiag-nosed and inadequately treated. Sometimes we are faced with patients who refuse to take medications. Oftentimes, com-bining psychotherapy, medica-tion, and other treatment modalities gives better results. How does exercise work? Exercise may have biochemical effects via release of endorphins and other neu-rotransmitters. Often, exercise is done in groups or with a trainer and, thus, the social contact may be critical. If the exercise is done outside the person’s home, the very act of getting out and doing something may be therapeutic. Exercise also acts as a diversion for negative thinking and helps take the patient out of the helpless, withdrawn, state of mind. What’s the evidence? 1. North, et al. A meta-analysis of 80 studies showed exercise decreased depres-sion scores significantly when com-pared to controls. The antidepressant effect increased with the duration of therapy and occurred with all types of regular exercise, independent of sex or age.1 2. Lawlor, et al. Another meta-analysis looked at 72 potentially relevant studies, but only 14 of these fulfilled the inclusion criteria. Methodologic weaknesses included: • randomization was adequately concealed in only three studies, • intention to treat analysis was undertaken in only two, and • assessment of outcome was blinded in only one. When compared with no treat-ment, exercise significantly reduced symptoms of depression. The effec