The differential effects of plasma from two groups of clinically similar schizophrenic patients on learning behavior in rats.

The effects of plasma from normal subjects and chronic schizophrenic patients were determined on the rate of learning a pole jump response in rats. The animals were trained to a buzzer CS and electroshock US. Mean trials to a 90 per cent avoidance criterion were determined using a 100 trial cut off. Plasma and other control solutions were given intraperitoneally in the morning and the procedure repeated in the afternoon with separate groups of rats. Test trials were initiated five minutes after injection. It was found that all plasma, in contrast to saline, produced an increase in the number of trials to learn the avoidance response. No difference in behavioral effects was noted comparing the plasma of all chronic schizophrenics to normals. However, within the chronic schizophrenic population there are subgroups whose plasma was differentially effective in reducing rate of learning. These results are preliminary and subject to continued experimentation. They are presented here to make others aware of the needto consider the existence of possible biologic subgroupings of schizophrenia in future investigations of the plasma-behavior interaction.