Differential patterns of executive dysfunction across depressive phenotype in schizophrenia and major depressive disorder.

Executive functioning (EF) deficits are common in both schizophrenia (SZ) and major depressive disorder (MDD). However, it remains unclear whether specific EF subdomains are differently affected in SZ and MDD, particularly in relation to depressive symptoms. This study aims to investigate EF subdomains in MDD, SZ with depressive symptoms (SZ-D), SZ without depressive symptoms (SZ-ND) and healthy controls (HC), and to explore the relationships between psychopathological symptoms and EF performance. A total of 213 participants were recruited, including 76 MDD, 81 SZ patients and 56 HC. EF was assessed using the n-back, Stroop color-word and more-odd shifting tasks. The 17-item Hamilton Depression Scale, Hamilton Anxiety Scale and Positive and Negative Syndrome Scale were used to assess depression, anxiety and psychopathological symptoms. In the 2-back task, SZ-D patients had longer response time (RT) (p < 0.01), while SZ-ND patients had lower accuracy rates (AR) (p < 0.01) compared to MDD patients and HC. In more-odd shifting task, SZ-D patients showed longer RT for shift cost (p < 0.01), and SZ-ND patients had lower AR for shift cost (p < 0.01) compared to MDD and HC. Multiple regression analysis revealed that negative symptoms were associated with AR in the 2-back condition in SZ-D, while in SZ-ND, negative symptoms was related to AR in the 1-back condition. SZ patients showed more severe EF dysfunction, with depressive symptoms in SZ primarily affecting response speed rather than accuracy. Negative symptoms were associated with EF dysfunction in both MDD and SZ patients.