Caffeine: use and effects in long-stay psychiatric patients.

In a double-blind crossover study of 26 long-stay schizophrenic patients, no correlation was found between caffeine consumption and levels of anxiety and depression. No significant changes in patients' behaviour or levels of anxiety and depression occurred when the wards changed to decaffeinated products. Serum caffeine levels confirmed compliance. No evidence was found to support a removal of caffeinated products from this group of patients.