Longitudinal stability of cognitive control in early psychosis: Nondegenerative deficits across diagnoses

Cognitive impairment, particularly in the domain of cognitive control, is characteristic of schizophrenia (SZ) spectrum and bipolar disorders (BDs). The longitudinal trajectory of these impairments, however, remains unclear. Indeed, some studies have observed degeneration and others stability or even improvement over time in these illnesses. Here we examined the longitudinal stability of the AX-Continuous Performance Task (AX-CPT), a cognitive control task, in 52 patients with recent-onset SZ (<2 years from first study measurement), 20 patients with recent-onset BD Type I with psychotic features, and 70 healthy control subjects. Subjects performed the AX-CPT at 2 time points separated by an average of 365 days (range 270-620). Previously identified deficits in cognitive control were replicated in both patient groups. No effects of time or interactions between time and diagnosis were observed. Intraclass correlation coefficients also suggested AX-CPT performance was stable across time for all diagnostic groups. Although performance was stable on average, a positive association was noted between change in cognitive control and change in disorganization symptom severity across patient groups. In conclusion, the present findings suggest that deficits in cognitive control are present in both disorders and stable over the early course of psychotic illness. No evidence was observed for progression or deterioration of cognitive control or differential recovery in SZ compared to BD. (PsycINFO Database Record (c) 2018 APA, all rights reserved).