The nonlinear, complex sequential organization of behavior in schizophrenic patients: Neurocognitive strategies and clinical correlations. Biol Psychiatry

Background: Thought disorder is a hallmark of schizo-phrenia and can be inferred from disorganized behavior. Measures of the sequential organization of behavior are important because they reflect the cognitive processes of the selection and sequencing of behavioral elements, which generate observable and analyzable behavioral patterns. In this context, sequences of choices generated by schizophrenic patients in a two-choice guessing task fluctuate significantly, which reflects an “oscillating dys-regulation ” between highly predictable and highly unpre-dictable subsequences within a single test session. In this study, we aimed to clarify the significance of dysregulation by seeing whether demographic, clinical, neuropsycholog-ical, and psychological measures predict the degree of dysregulation observed on this two-choice task. Methods: Thirty schizophrenic patients repeatedly per-formed a LEFT or RIGHT key press that was followed by a stimulus, which occurred randomly on the left or right side of the computer screen. Thus, the stimulus location had nothing to do with the key press behavior. The range of key press sequence predictabilities as measured by the dynamical entropy was used to quantify the dysregulation of response sequences and reflects the range of fixity and randomness of the responses. A factor analysis was performed and step-wise multiple regression analyses were used to relate the factor scores to demographic