Behavioural dysregulation of decision-making in deficit but not nondeficit schizophrenia patients.

This study aimed to determine whether deficit but not nondeficit schizophrenia showed dysregulation of decision-making. In a two-choice prediction task, the subject is asked to predict whether a stimulus appears on the left or right side of a computer screen. Schizophrenia patients were divided into 12 patients with and 12 patients without deficit syndrome and compared to 12 healthy control subjects. Dynamical entropy and mutual information analyses were used to determine underlying strategies and the degree to which sequences of responses are nonrandom. When compared to controls, deficit but not nondeficit schizophrenia patients showed a dysregulation of decision-making characterized by an increased oscillation between highly predictable and highly unpredictable response sequences. Moreover, in deficit patients, the previous choice was more predictive of the current response. Therefore, the two-choice prediction task may be useful in differentiating between deficit and nondeficit schizophrenia.