Transketolase activity in psychiatric patients.

The thiamine status of 42 physically healthy nonalcoholic psychiatric inpatients was evaluated by measuring transketolase activity in a hemolysate of their red blood cells, before and after addition of thiamine pyrophosphate to the hemolysate. Sixteen patients (38%) showed evidence of thiamine deficiency. Five of these patients had received thiamine-containing vitamins for a period of from 2 fo 47 days prior to testing, suggesting that poor nutrition may not fully account for the thiamine deficiency observed.