Affiliation:
1. Department of Neuropsychiatry, Kanazawa Medical University, Ishikawa, Japan
2. Department of Psychiatry and Psychotherapy, Gifu University Graduate School of Medicine, Gifu, Japan
3. Department of General Internal Medicine, Kanazawa Medical University, Ishikawa, Japan
Abstract
Abstract
Background
Patients with schizophrenia (SCZ) display impaired executive functions compared with healthy controls (HCs). Furthermore, unaffected first-degree relatives (FRs) of patients with SCZ independently perform worse executive functions than do HCs. However, few studies have investigated the differences in executive functions assessed among patients with SCZ, FRs, and HCs, and the findings are inconsistent.
Methods
We investigated diagnostic differences in executive functions, namely (1) numbers of categories achieved (CA), (2) total errors (TE), and (3) percentage of perseverative errors of Nelson types (%PEN), using the Wisconsin card sorting test among patients with SCZ (n = 116), unaffected FRs (n = 62), and HCs (n = 146) at a single institute. Correlations between these executive functions and clinical variables were investigated.
Results
Significant differences existed in all executive functions among diagnostic groups (CA, F2,319 = 15.5, P = 3.71 × 10–7; TE, F2,319 = 16.2, P = 2.06 × 10–7; and %PEN, F2,319 = 21.3, P = 2.15 × 10–9). Patients with SCZ had fewer CA and more TE and %PEN than those of HCs (CA, Cohen’s d = −0.70, P = 5.49 × 10–8; TE, d = 0.70, P = 5.62 × 10–8; and %PEN, d = 0.82, P = 2.85 × 10−10) and FRs (TE, d = 0.46, P = 3.73 × 10–3 and %PEN, d = 0.38, P = .017). Of the 3 executive functions, CA and %PEN of FRs were intermediately impaired between patients with SCZ and HCs (CA, d = −0.41, P = .011 and %PEN, d = 0.41, P = .012). In contrast, no significant difference in TE existed between FRs and HCs (d = 0.22, P = .18). Although CA and TE were affected by the duration of illness (P < .017), %PEN was not affected by any clinical variable in patients with SCZ (P > .017).
Conclusions
Executive function, particularly %PEN, could be a useful intermediate phenotype for understanding the genetic mechanisms implicated in SCZ pathophysiology.
Funder
Kanazawa Medical University
Smoking Research Foundation
Takeda Science Foundation
Uehara Memorial Foundation
Japan Society for the Promotion of Science
YOKOYAMA Foundation for Clinical Pharmacol
Publisher
Oxford University Press (OUP)
Subject
Pharmacology (medical),Psychiatry and Mental health,Pharmacology