lundi 30 janvier 2012

EXERCISE AND DEPRESSION

Depression is a prevalent problem in today’s society. Clinical depression affects 2–5% of Americans each year (Kessler et al., 1994) and it is estimated that patients suffering from clinical depression make up 6–8% of general medical practices (Katon & Schulberg, 1992). Depression is also costly to the health care system in that depressed individuals annually spend 1.5 times more on health care than nondepressed individuals, and those being treated with antidepressants spend three times more on outpatient pharmacy costs than those not on drug therapy (Simon, VonKorff, & Barlow, 1995). These costs have led to increased governmental pressure to reduce health care costs in America. If available and effective, alternative low-cost therapies that do not have negative side effects need to be incorporated into treatment plans. Exercise has been proposed as an alternative or adjunct to more traditional approaches for treating depression (Hales & Travis, 1987; Martinsen, 1987, 1990).
     The research on exercise and depression has a long history of investigators (Franz & Hamilton, 1905; Vaux, 1926) suggesting a relationship between exercise and decreased depression. Since the early 1900s, there have been over 100 studies examining this relationship, and many narrative reviews on this topic have also been conducted. During the 1990s there have been at least five meta-analytic reviews (Craft, 1997; Calfas & Taylor, 1994; Kugler et al., 1994; McDonald & Hodgdon, 1991; North, McCullagh, & Tran, 1990) that have examined studies ranging from as few as nine (Calfas & Taylor, 1994) to as many as 80 (North et al., 1990). Across these five meta-analytic reviews, the results consistently show that both acute and chronic exercise are related to a significant reduction in depression. These effects are generally “moderate” in magnitude (i.e., larger than the anxiety-reducing effects noted earlier) and occur for subjects who were classified as nondepressed, clinically depressed, or mentally ill. The findings indicate that the antidepressant effect of exercise begins as early as the first session of exercise and persists beyond the end of the exercise program (Craft, 1997; North et al., 1990). These effects are also consistent across age, gender, exercise group size, and type of depression inventory.
     Exercise was shown to produce larger antidepressant effects when: (a) the exercise training program was longer than nine weeks and involved more sessions (Craft, 1997; North et al., 1990); (b) exercise was of longer duration, higher intensity, and performed a greater number of days per week (Craft, 1997); and (c) subjects were classified as medical rehabilitation patients (North et al., 1991) and, based on questionnaire instruments, were classified as moderately/severely depressed compared to mildly/moderately depressed (Craft, 1997). The latter effect is limited since only one study used individuals who were classified as severely depressed and only two studies used individuals who were classified as moderately to severely depressed. Although limited at this time, this finding calls into question the conclusions of several narrative reviews (Gleser & Mendelberg, 1990; Martinsen, 1987, 1993, 1994), which indicate that exercise has antidepressant effects only for those who are initially mild to moderately depressed.
     The meta-analyses are inconsistent when comparing exercise to the more traditional treatments for depression, such as psychotherapy and behavioral interventions (e.g., relaxation, meditation), and this may be related to the types of subjects employed. In examining all types of subjects, North et al. (1990) found that exercise decreased depression more than relaxation training or engaging in enjoyable activities, but did not produce effects that were different from psychotherapy. Craft (1997), using only clinically depressed subjects, found that exercise produced the same effects as psychotherapy, behavioral interventions, and social contact. Exercise used in combination with individual psychotherapy or exercise together with drug therapy produced the largest effects; however, these effects were not significantly different from the effect produced by exercise alone (Craft, 1997).
     That exercise is at least as effective as more traditional therapies is encouraging, especially considering the time and cost involved with treatments like psychotherapy. Exercise may be a positive adjunct for the treatment of depression since exercise provides additional health benefits (e.g., increase in muscle tone and decreased incidence of heart disease and obesity) that behavioral interventions do not. Thus, since exercise is cost effective, has positive health benefits, and is effective in alleviating depression, it is a viable adjunct or alternative to many of the more traditional therapies. Future research also needs to examine the possibility of systematically lowering antidepressant medication dosages while concurrently supplementing treatment with exercise.

Aucun commentaire:

Enregistrer un commentaire