Disordered thinking in schizophrenia: intermingling and loss of set.

In a study of schizophrenic thought pathology, potential loss of set and intermingling were examined. The responses of 36 acute psychiatric patients who showed intermingling were analyzed. Intermingling, frequently seen in the speech and thinking of schizophrenic patients, involves the blending of personal material from one's experiences into one's thinking and communication, leading to bizarre and inappropriate speech. The results indicated that intermingling frequently leads to some loss of goal-directed thinking, but not usually to complete loss of set. Patients adopt new sets based partly on the original topic and partly on their own personal idiosyncratic concerns. The apparent "looseness" of schizophrenic patients is based on thematic shifts to idiosyncratic ideas, often from the beginning of their responses, rather than on word-to-word associative looseness. Intermingling of personal concerns typically occurs in a nonfragmented fashion. Schizophrenics and other psychotic patients show significantly more intermingling of personal material in open and undisguised fashion, as though they do not recognize how inappropriate their intermingling appears. The results suggest that although the intrusion of personal material is task inappropriate, it still represents a form of systematic, goal-oriented thinking.