Interconnected Cognitive and Neuroimmune Impairments in Schizophrenia: Modulating Effects of Antipsychotic Type, Illness Duration, and Symptom Severity

OBJECTIVE: Cognitive impairment in schizophrenia (SCZ) is associated with neuroinflammation and neurotrophic dysregulation. The role of pro-inflammatory interleukins and brain-derived neurotrophic factor (BDNF) in cognitive deficits remains unclear. We aimed to examine the associations between IL-1β, IL-2, IL-6, BDNF, and cognitive function in patients with SCZ with typical or atypical antipsychotics. METHODS: Participants included 162 healthy controls (mean age = 33.6 ± 2.0 years), 88 patients with SCZ receiving typical antipsychotics (36.4 ± 6.4 years), and 62 receiving atypical antipsychotics (34.0 ± 4.0 years). Cognitive performance was evaluated using a battery of attentional, executive, and visuospatial working memory tasks. Data were analyzed using machine-learning approaches, multivariate statistics, and structural equation modeling. RESULTS: SCZ Patients exhibited marked cognitive impairments alongside lower BDNF concentrations and elevated interleukin levels, with the greatest deviations observed among those receiving typical antipsychotic treatment. Higher medication dosages and longer illness duration were associated with greater cognitive decline and stronger neuroimmune dysregulation. CONCLUSIONS: The findings indicate that elevated cytokines and reduced neurotrophic support may contribute to cognitive impairment, whereas persistent cognitive dysfunction can further amplify inflammatory activity. This complexity suggests the need to broaden current assessment approaches and systematically examine biomarkers together with clinical features.