Psychophysiological studies in schizophrenic patients selected on the basis of a "genetic marker"

Psychophysiological studies in schizophrenics have generally resulted in contradictory and inconclusive reports. The purpose of the present study was to determine whether a better psychophysiological separation of schizophrenic and control subjects could be accomplished by selecting them on the basis of a biological marker: the high plexus visualization score (PVS). Finger blood flow, skin temperature and electrodermal recovery rates were studied in 64 male schizophrenics (33 high PVS and 31 low PVS) and 24 male controls (10 high PVS and 14 low PVS) matched for age. All control subjects and 30 of the schizophrenics (16 high PVS and 14 low PVS) had been drug-free for at least 1 month. They were studied in a sound attenuated, temperature controlled room under 12 experimental conditions. The results demonstrate that, as predicted, schizophrenics with high PVS have the lowest finger blood flow rates, the lowest skin temperatures and the slowest GSR recovery rates of all groups studied. The largest difference in all three variables was found between high PVS schizophrenics and high PVS controls. The blood flow rates and the skin temperature were higher and the electrodermal responses were fewer in patients taking medications than in those receiving placebos. A suggestion of a bimodal distribution into "responders" and "non-responders" was apparent only in patients receiving medications.