An investigation into the effect of exercise on clinical depression
- Problems with depression.
- Profile of Mood States (POMS).
- Traditional treatments for depression.
- Epidemiological evidence.
- The first study conducted by William Morgan.
- The second study: Conducted by Camacho, Roberts, Lazarus, Kaplan and Cohen.
- The work of Lawlor & Hopker.
- Psychological mechanisms.
- Critique and future directions.
- Dichotomous outcomes along with continuous ones.
Problems with depression are by no means limited to those who are clinically diagnosed as being so. Generalised, negative affect is experienced by everyone throughout the course of a lifetime. Usually, non clinical depression is linked to some kind of stressor in the environment which can be clearly identified, for example, the termination of a job. It is only when these depressive episodes go further than certain boundaries of intensity, duration and frequency can the disorder can be labelled clinical depression. Depressive symptoms, e.g. sadness, disturbed sleep and fatigue can also be symptoms of other medical conditions (for example stroke) however, in this situation depression may not require a separate diagnosis. Clinical depression is a very prevalent problem in today's society; 15% of people will have an episode of major depression in their lives and it is said to be the fourth most common cause of disability worldwide (NHS Website 2004).
[...] Lawlor et al also state that they do not think it is possible to define the effectiveness of exercise in treating depression from the available literature although it may alleviate some of the symptoms Until more is known about the effectiveness of exercise on depression standard treatment should continue especially in the more severe cases. More longitudinal designs are needed (for 12 months or more) (Craft and Landers 1998) within the area. In a study by (Martinsen, Medhus, & Sandvik, 1985) subjects who had fitness gains of over 30% had greater reductions in depression than those in the 15-30% bracket. [...]
[...] The effect of exercise on clinical depression and depression resulting from mental illness: A meta analysis. Journal of sport and exercise psychology 339-357. Diagnostic and Statistical Manual of Mental Disorders. American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed., text revision). Washington, DC: Author. Dimeo, F., Bauer, M., Varahram, I., Proest, G., & Halter, U. (2001). Benefits from aerobic exercise in patients with major depression: a pilot study. British journal of sports medicine, 35(2) 114-117. Dishman, R.K. [...]
[...] North et al (1990) examined the relationship between exercise and depression in a total of 80 studies and found an overall effect size of - This indicated that depression decreased more in the exercise groups than the comparison groups. Craft and Landers (1998) found similar effects to these in their meta analysis on clinical depression and depression resulting from mental illness. Results from 30 studies, many of which were on unpublished dissertations, showed an effect size of -.72, therefore depressed individuals who exercised were -.72 of a standard deviation less depressed than those who did not exercise. [...]