Effects of caffeine on behavior of schizophrenic inpatients.

The present study replicates that of De Freitas and Schwartz (1979), using more typical chronic patients (on open wards rather than locked wards), and monitoring coffee intake with serum caffeine levels. The serum caffeine levels observed indicate that caffeine can be effectively manipulated on an open ward by switching the type of coffee served. Contrary to our predictions, no significant improvements in patients' behavior occurred when decaffeinated coffee was first introduced, nor was there any deterioration when regular coffee was reinstated. Only after decaffeinated coffee was introduced for the second time did any of the predicted changes occur; however, the improvements were few in number and may be accounted for by the considerable effect of time per se across all time periods. Although the findings cannot be generalized to all psychiatric patients, the results do not support recent calls for a switch to decaffeinated coffee for this population of inpatients (i.e., chronic schizophrenic patients on high doses of neuroleptics who drink large amounts of coffee).