Medical Hypotheses (2000) 54(6), 861–863 © 2000 Harcourt Publishers Ltd doi: 10.1054/mehy.1999.0931, available online at http://www.idealibrary.com on
The possible effect of seasonal mood changes on the seasonal distribution of myocardial infarction L. Sher Rockville, Maryland, USA
Summary The incidence of acute myocardial infarction is increased in the winter months. Seasonality of mood and behavior is common throughout the general population. Increased cardiovascular morbidity and mortality in patients with depressive disorders have been well documented. The author suggests that seasonal mood changes may contribute to the increased incidence of acute myocardial infarction in the winter. The author further suggests that patients with cardiovascular disorders who suffer from seasonal mood changes should be identified and receive the appropriate treatment for seasonal depressive symptoms that may improve the quality of life for these individuals and reduce their incidence of acute myocardial infarction. © 2000 Harcourt Publishers Ltd
The importance of mind–body relationships is often overlooked and underestimated. Contemporary technomedicine does not pay much attention to the subtle and complex relation between mind and body. However, the influence of psychological factors on the physical and mental condition of healthy and sick people is very considerable.
analyzed as well as in different geographic areas. These results suggested that the chronobiology of seasonal variation in AMI may be affected by factors independent of climate. In the 1930s an increase in mortality from AMI during the winter was reported for the first time (2,3). Many studies suggested that mortality from coronary heart disease is increased in the winter months (4–8). Possibly, this increase in mortality is secondary to an increased incidence of AMI during the winter.
DEVELOPMENT OF THE HYPOTHESIS
Current concept of seasonality
Seasonal distribution of myocardial infarction
Since ancient times people have known about the seasonal changes in mood and behavior (9). The concept of seasonal mood disorders dates to the dawn of medicine. Seasonal depressions were described by Hippocrates circa 400 BC (10). About 1500 years ago Posidonius wrote that ‘melancholy occurs in Autumn, whereas mania in Summer’ (11). In 1894 Cook linked seasonal loss of sunlight to a mood disorder (12). Seasonal changes in mood were also described by Esquirol in 1845 (13) and by Kraepelin in 1921 (14). Seasonal changes in mood and behavior have been studied extensively over the past two decades (15–18). The degree to which seasonal changes affect mood and
INTRODUCTION
A recent observational study suggests that there is a seasonal pattern in the occurrence of acute myocardial infarction (AMI) that is characterized by a marked peak of cases in the winter months and a nadir in the summer months (1). This pattern was observed in all sub-groups
Received 20 January 1999 Accepted 4 June 1999 Correspondence to: Leo Sher MD, 5901 Montrose Road, #S408 Rockville, MD 20852, USA
861
862
Sher
behavior has been called ‘seasonality’ (15). Seasonality can manifest to different degrees in different individuals. Seasonality can be viewed in dimensional terms ranging from those who show no seasonal changes to those who show more extreme changes with the seasons. ‘Seasonal affective disorder’ (SAD), a condition where depressions in fall and winter alternate with non-depressed periods in the spring and summer, is an extreme form of seasonality (16). Seasonality of mood and behavior is common in the general population (15,17). A survey in the Washington area in the USA found that approximately 4% of the population have winter SAD and over 10% more have sub-syndromal SAD (15). 27% of respondents reported that changes with the seasons were a problem for them, 66% reported seasonal changes in energy level, 64% reported some seasonal changes in mood, and 49% reported seasonal changes in weight. Another survey, in New York City, indicated approximately 6% with potential clinical severity, 18% reporting milder symptoms that are bothersome, and 35% noting symptoms but without complaint (17).
behavior is common throughout the general population. Increased cardiovascular morbidity and mortality in patients with depressive disorders have been well documented. Hence, it is reasonable to suggest that seasonal mood changes may contribute to the increased incidence of AMI in the winter. This hypothesis has practical applications: • •
• •
Patients with cardiovascular disorders who suffer from seasonal mood changes should be identified. These patients should receive the appropriate treatment (light therapy, etc) for seasonal depressive symptoms, which may improve the quality of life for these individuals and reduce their incidence of acute myocardial infarction. The medical management of these patients should be more careful during the winter months. Future studies of pathophysiology, clinical features, and treatment of seasonal mood disorders in patients with cardiovascular illness are merited.
REFERENCES Effects of mood on cardiovascular function Psychological factors have a very considerable impact on the cardiovascular system (19–25). Many studies have documented increased cardiovascular morbidity and mortality in patients with depressive disorders (19–24). Depression has been implicated as an independent risk factor in the pathophysiologic progression of cardiovascular disease (19). In a study of patients undergoing diagnostic cardiac catheterization and arteriography, concomitant major depression was the best predictor of cardiac events during a 1-year follow-up (20). In patients with congestive heart failure, depressive symptoms are a stronger predictor of New York Heart Association functional class than is left ventricular ejection fraction (21). Depression, stress, anger, anxiety, and social isolation have been shown to substantially increase risk for myocardial infarction in coronary artery disease patients (19,20,22–24). Pathophysiologic alterations that may contribute to increased vulnerability of depressed patients to cardiovascular disorders include hyperactivity of the sympathoadrenal system, alterations in serotonergic transmission, and exaggerated platelet reactivity (19). The immune system and the infectious process may also be involved in the effects of psychological factors on the cardiovascular system (25).
DISCUSSION Studies have suggested that the incidence of AMI is increased in the winter months. Seasonality of mood and Medical Hypotheses (2000) 54(6), 861–863
1. Spencer F. A., Goldberg R. J., Becker R. C., Gore J. M. Seasonal distribution of acute myocardial infarction in the second National Registry of Myocardial Infarction. J Am Coll Cardiol 1998; 31: 1226–1233. 2. Masters A. M., Dack S., Jaffe H. L. Factors and events associated with onset of coronary artery thrombosis. JAMA 1937; 109: 546–549. 3. Rosahn P. D. Incidence of coronary artery thrombosis. JAMA 1937; 109: 1294–1299. 4. Baker-Blocker A. Winter weather and cardiovascular mortality in Minneapolis-St. Paul. Am J Public Health 1982; 72: 261–265. 5. Rogers W. J., Bowlby L. J., Chandra N. C. et al. Treatment of myocardial infarction in the United States (1990 to 1993): observations from the National Registry of Myocardial Infarction. Circulation 1994; 90: 2103–2114. 6. Marchant B., Ranjadayalan K., Stevenson R., Wilkinson P., Timmis A. D. Circadian and seasonal factors in the pathogenesis of acute myocardial infarction: the influence of environmental temperature. Br Heart J 1993; 69: 385–387. 7. Beard M. C., Fuster V., Elveback L. R. Daily and seasonal variation in sudden cardiac death, Rochester, Minnesota, 1950–1975. Mayo Clin Proc 1982; 57: 704–706. 8. Ornato J. P., Siegel L., Craren E. J., Nelson N. Increased incidence of cardiac death attributed to acute myocardial infarction during winter. Coronary Artery Dis 1990; 1: 199–203. 9. Wehr T. A. Seasonal affective disorder. A historical overview. In: Rosenthal N. E., Blehar M. C., eds. Seasonal affective disorder and phototherapy. New York: Guilford Press, 1989; 11–32. 10. Hippocrates. Aphorisms. In: Hippocrates. Cambridge, MA: Harvard University Press, 1931: 128–129. 11. Roccatagliata G. A history of ancient psychiatry. Westport CT: Greenwood Press, 1986. 12. Cook F. A. Gynecology and obstetrics among the Eskimos. Brooklyn Med J 1894; 8: 154–169. 13. Esquirol E. Mental Maladies: Treatise on Insanity. Hunt E. K., (ed.) Lea & Blanchard, 1845.
© 2000 Harcourt Publishers Ltd
Seasonal distribution of myocardial infarction
14. Kraepelin E. Manic-Depressive Illness and Paranoia. R. M. Barklay (Transl) Robertson G. M., Livingstone E., Livingstone M., eds. Edinburgh: E&S Livingstone, 1921. 15. Kasper S., Wehr, T. A., Bartko J. J., Gaist, P., Rosenthal N. E. Epidemiological findings of seasonal changes in mood and behavior. Arch Gen Psychiatry 1989; 46: 823–833. 16. Rosenthal N. E., Sack D. A., Gillin J. C. et al. Seasonal affective disorder: a description of the syndrome and preliminary findings with light therapy. Arch Gen Psychiatry 1984; 41: 72–80. 17. Terman M. On the question of mechanism in phototherapy for seasonal affective disorder: considerations of clinical efficacy and epidemiology. J Biol Rhythms 1988; 3: 155–172. 18. Sher L., Goldman D., Ozaki N., Rosenthal N. E. The role of genetic factors in the etiology of seasonal affective disorder and seasonality. J Affect Disord (in press). 19. Nemeroff C. B., Musselman D. L., Evans D. L. Depression and cardiovascular disease. Depress Anxiety 1998; 8 (Suppl 1): 71–79. 20. Carney R. M., Rich M. W., Tevelde A., Saini J., Clark K., Jaffe A. S. Major depressive disorder predicts cardiac events in patients
© 2000 Harcourt Publishers Ltd
21.
22.
23.
24.
25.
863
with coronary artery disease. Psychosom Med 1988; 50: 627–633. Skala J. A., Freedland K. E., Carney R. M. Depressive symptoms and functional status in patients with congestive heart failure. Ann Behavior Med 1995; 17: S130. Bohus B., Koolhaas J. Stress and cardiovascular system: central and peripheral physiological mechanisms. In: Stanford S. C., Salmon P., eds. Stress. From Synapse to Syndrome. London: Academic Press, 1993: 76–117. Frasure-Smith N., Lesperance F., Talajic M. The impact of negative emotions on prognosis following myocardial infarction: is it more than depression? Health Psychol 1995; 14: 388–398. Carney R. M., Freedland K. E., Sheline Y. I., Weiss E. S. Depression and coronary heart disease: a review for cardiologists. Clin Cardiol 1997; 20: 196–200. Sher L. The effects of psychological factors on the development of cardiovascular pathology: the role of the immune system and infection. Med Hypotheses (in press).
Medical Hypotheses (2000) 54(6), 861–863