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Trait contributions of complex dysregulated behavioral organization in schizophrenic patients
M P Paulus1, M H Rapaport, D L Braff
1University of California San Diego, Laboratory of Biological Dynamics and Theoretical Medicine, Department of Psychiatry, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA.
Background:
The "temporal architecture" of behavior is a construct that can be used to quantify the structure of behavioral sequences in the temporal domain-for example, by using a two-choice prediction task to investigate how past responses, stimuli, and outcomes influence the decision-making process. Using this task, previous investigations of the temporal architecture of the behavior in schizophrenic patients have identified an increased frequency of alternating highly predictable and highly unpredictable response sequences in the same test session in the same patient. Here, the hypothesis is tested that this dysregulation is stable over time and independent of psychosocial factors and symptomatic fluctuations.
Methods:
Ninety-one schizophrenic patients were tested on a 128 trial version of the two-choice prediction task; of those, 58 subjects completed a retest session 40 days later. Three sets of measures were obtained: simple response biases, dynamical entropy, and mutual information functions. These measures were subjected to a factor analysis, and the reliability of the resulting factors was examined.
Results:
First, three factors were obtained, which quantify 1) the level of dysregulation on this task; 2) the extent to which a win-stay/lose-shift strategy was used; and 3) the amount of simple response perseveration. Second, Crohnbach alpha for these factors was .699, .721, and .458, respectively. Third, there were no significant differences in the level of these factors within individual patients at the two time points. Fourth, neither symptom measures (Scale for the Assessment of Positive Symptoms and Scale for the Assessment of Negative Symptoms subscale scores) nor psychosocial or clinical variables (age, gender, illness duration, medication status) were able to predict the level of these factors at test or at retest.
Conclusions:
These results support the hypothesis that the fundamental dysregulation of the temporal architecture of behavior in schizophrenic patients is stable across time and independent of symptomatic status. Future studies will examine the heritability of this dysfunction.