Background: Decision-making is a complex process, which can be assessed experimentally by the two-choice prediction task. Error-rate, i.e. the frequency of incorrect predictions during this task, is an important factor for the response selection during decision-making. This investigation examined whether the frequency of incorrect predictions has an augmented effect on the number of different strategies underlying decision-making in patients with panic disorder.
Methods: Patients with a DSM-IV diagnosis of panic disorder (PD; N=18), unipolar major depressive disorder (MDD; N=18) and normal comparison subjects (C; N=35) were tested with the two-choice prediction task using three error-rate conditions (20, 50, or 80%). The dynamical entropy of the response sequences was used to quantify the number of different strategies generated during the different error-rates.
Results: At 20% error-rates, panic disorder subjects when compared to MDD and C subjects generated more strategies and switched more frequently between strategies as measured by the dynamical entropy and the range of local dynamical entropies. Response bias measures during the two-choice prediction task and post-test self-assessment did not differ between panic disorder subjects and MDD or C subjects.
Limitations: First, panic disorder subjects were medicated. Second, the frequency and intensity of panic attacks and the degree of avoidance behaviors, was not assessed. Third, subjects were tested once only.
Conclusions: Panic disorder subjects show uniformly high response sequence unpredictability in the presence of low error-rates, which is consistent with continued search for an optimal response strategy even when the error-rate is low.