“In the United States, burnout is not considered a clinical disorder. It is a syn- drome fundamentally linked to the workplace and, in the popular culture, to parenting and athletic performance. There is a lack of U.S. national data on burnout, but some studies of single occupations show that the prevalence of burnout in the work context is particularly high within human service occupations. Figures range from 9% among nurses  to as high as 45% among medical students . Burnout is the result of prolonged exposure to chronic job stressors . Christina Maslach developed an instrument to measure burnout which consists of three parts: emotional exhaustion, depersonalization or cynicism, and lack of professional efficacy or personal accomplishment . Emotional exhaustion is considered to be the main component of the syndrome, referring to a feeling of depleted energy or emotional resources . Depersonalization or cynicism refers to negative feelings and distancing from others at work and is the “interpersonal” component of the syndrome. Reduced personal accomplishment is a lowered sense of productivity and self-efficacy and represents the “self-evaluation” aspect of burnout.
Anxiety, burnout, and depression can all be present in the same individuals. Mechanisms explaining the relationship between these outcomes and work stress are not well understood  and, while undoubtedly related to each other, they may have different physiological effects:
“During its early stages, burnout may occur concomitantly with a high level of anxiety because of the active coping behaviors that usually entail a high level of arousal. When and if these coping behaviors prove ineffective, the individual may give up and engage in emotional detachment and defensive behaviors that may lead to depressive symptoms [19, p. 356].
Four cross-sectional studies have investigated the job demand and control model in relationship to burnout [44, 50]. Three of these four studies showed that demands and low control were associated with burnout. The non-supportive fourth study was of construction workers where burnout is not found to be as prevalent as in human service work. One study also investigated the role of social support among female social workers and found that those workers with high demands, low control, and low support were at greater risk of burnout .”
Burnout is considered more closely related to chronic stress at work while depression is considered to be more pervasive and caused by a multiplicity of factors from family/genetic history, personality, and past and present exposure to stressful life events [23, 24], as well as chronic work stressors. A recent study demonstrated a strong association between burnout and depression, where those with burnout were eight times more likely to also suffer from depressive symptoms and five times more likely to experience depression .
Burnout might be a pathway through which those with highly demanding jobs and with little control over the work environment develop depression. A recent study of more than 3,000 Finnish employees looked at the association between job strain, burnout, and depression . They found that those with high job strain were 7.4 times more likely than those with low job strain to have burnout and that those with job strain had a 3.8 times higher risk for depressive symptoms. However, they also found that the increased risk for depressive symptoms and for depression as a disorder due to high job strain was reduced by 69% after adjusting for burnout. These findings suggest there may be multiple pathways leading to work-related depression (see Figure 3). However, because it was a cross-sectional study, alternate explanations of the results are possible; for example, there may be individuals in the study whose depression started before they were exposed to job strain and thus was caused by other risk factors.”
Taken from: Schnall PL, Dobson M, Rosskam E, Editors Unhealthy Work: Causes, Consequences, Cures. Baywood Publishing, 2009.
14. Melchior, M., H. Philipsen, H. Abu-Saad, R. Halfens, A. Van Der Berg, and P. Gassman, The Effectiveness of Primary Nursing on Burnout among Psychiatric Nurses in Long-Stay Settings, Journal of Advances in Nursing, 24, pp. 694-702, 1996.
15. Guthrie, E., D. Black, H. Bagalkote, C. Shaw, M. Campbell, and F. Creed, Psychological Stress and Burnout in Medical Students: A Five-Year Prospective Longitudinal Study, Journal of the Royal Society of Medicine, 91, pp. 237-243, 1998.
16. Melamed, S., A. Shirom, S. Toker, S. Berliner, and I. Shapira, Burnout and Risk of Cardiovascular Disease: Evidence, Possible Casual Paths, and Promising Research Directions, Psychological Bulletin, 132:3, pp. 327-353, 2006.
17. Maslach, C., S. E. Jackson, and M. P. Leiter, Maslach Burnout Inventory Manual,Consulting Psychologist Press, Palo Alto, CA, pp. 19-26, 1996.
18. Glass, D. C. and J. D. McKnight, Perceived Control, Depressive Symptomatology, and Professional Burnout: A Review of the Evidence, Psychology and Health, 11, pp. 23-48, 1996.