Heat Stroke and Schizophrenia

Classic heat strokes occur in epidemics in civilian population, especially those with preexisting disease, during periods of sustained high ambient temperatures and humidity as seen during summer heat (Yarbrough 1992). 

The city of Chennai in southern India experienced for  the first time a high incidence of  heat stroke in the summer of 1998 during an unprecedented 23-day long spell of hot and humid climate heat wave ever recorded in the city. (Mean maximum temperature=41.3 C and mean relative humidity=74.6%). During the 23-day spell of heat wave 81 cases of heat stroke were seen at two hospitals in the city from which this data was available to me.

The emphasis of this brief report  is on the occurrence of heatstroke in schizophrenia patients.

Many of these subjects (60 /81) had some pre-existing chronic medical illnesses like diabetes mellitus, organic brain disease and cardiovascular disorders and nearly all of them (90%) were receiving medication for the medical conditions. There were nine patients (6men and 3 women) on treatment for schizophrenia. Medical conditions like diabetes, organic brain syndromes and cardiovascular disorders and drugs like beta- blockers and psychotropic drugs are known to increase risk for developing heat stroke ( Keatinge 1987; Yarbrough 1992).   The mean age of the patients was 63.6 years, an age group with known vulnerability to heat stroke (Yarbrough 1992). The significant observation was that the patients of schizophrenia were  much young (mean 43.5 years) in striking contrast to 61.3 years of the diabetics, 67.2 years of those with organic brain disorders 73.4 years of those with cardiovascular disorders and 66.3 years of those with no pre-existing medical illness.   On this comparison of persons who were healthy before sunstroke and those with medical illness patients with patients of schizophrenia it appears that the vulnerability to heat stroke in the latter is not merely due to drugs and old age. Does the illness and its associated neuropathology itself increase the vulnerability of schizophrenia patient to heatstroke? A neurotransmitter substrate (e.g. dopamine) common for schizophrenia as well as dysfunctional heat regulation might account for the vulnerability of patients of schizophrenia to heat stroke even when they are young.          

References:

Keatinge WR. (1987) Heat. In: Weathrall DJ, Ledingham JGG, Warrell DA, eds. Oxford Textbook of Medicine. 2nd ed. London: ELBS/Oxford University Press ; : 6.92-6.93.

Yarbrough B. (1992) Heat illness. In:  Rosen P, Barkin RM, Braen GR et al, eds. Emergency Medicine: Concepts and clinical practice. 3rd ed. St. Louis: Mosby Year Book ; : 944-964.