Relationship between cognitive functions and serum neurotrophic factor levels in long-term hospitalized male patients with schizophrenia.

Objective: This study explored the changes in serum neurotrophic factor levels, the status of cognitive function, event-related potential P300, and the relationships between serum neurotrophic factor levels and cognitive functions, as well as event-related potential P300 in male schizophrenia patients with long-term hospitalization.

Methods: A total of 82 male schizophrenia patients with long-term hospitalization and 52 healthy controls were recruited. Cognitive functions were evaluated in all participants, including verbal fluency function, attention function, executive function, and spatial function. Event-related potential P300 latency and amplitude were recorded using the Nicolet Viking Quest evoked potential system (USA). The serum levels of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) were measured in all participants using enzyme-linked immunosorbent assay (ELISA).

Results: The patient group exhibited significantly poorer performance in all cognitive functions compared to the control group (p < 0.05). The patient group exhibited a statistically significant prolongation in P300 latency and a reduction in P300 amplitude compared to the control group (P < 0.01). In addition, serum BDNF levels were significantly lower in the patient group (9.1 ± 2.1 ng/ml) compared to the control group (11.6 ± 2.3 ng/ml, P < 0.01). Serum GDNF levels were 603.4 ± 182.6 pg/ml in the patient group and 610.2 ± 176.3 pg/ml in the control group, showing no statistically significant difference (P > 0.05). Onset levels were significantly correlated with almost all cognitive functions. BDNF levels were correlated to digital cancellation test scores (P < 0.05) and trail making test part B (TMT-part B) scores (P < 0.05). Moreover, a correlation was found between GDNF levels and block design test scores (P < 0.05). The latency of P300 was correlated to digital cancellation test scores (P < 0.01) and trail making test part A (TMT-part A) scores (P < 0.05). The amplitude of P300 was correlated with digital cancellation test scores (P < 0.01).

Conclusions: This study reveals that patients with chronic schizophrenia suffer from notable cognitive deficits during long-term hospitalization, which is linked to specific clinical characteristics. The patient group exhibited significantly lower serum BDNF levels than the control group. Event-related potential P300 testing revealed prolonged latency and reduced amplitude in patients. Serum BDNF and GDNF levels were selectively correlated with specific cognitive function performance.