The flicker-fusion threshold in schizophrenia and depression.

The flicker-fusion threshold was determined in 76 patients who complained of depression and who were diagnosed as suffering from either schizophrenia or depression. It was found to be lowered in schizophrenia and lowered further in depression as compared with 28 healthy volunteers. The differences between the three groups were all highly significant with P less than 0.0005 in each case. The flicker-fusion threshold was found to be lowered by intravenous chlorpromazine and raised by intravenous amitriptyline, so it is unlikely that these differences were due to medication that the patients had been taking.