Abstract
Background: Recent literature suggests that schizophrenia is linked to an abnormal response of the immune system. Interferon γ is a cytokine that plays an important role in the regulation of the immune system and acts as a mediator between immune stimulation and the kynurenine pathway, which has also been a major area of interest in schizophrenia. Additionally, previous studies have shown that serum interferon γ levels are related to cognitive abilities. The objectives of the present study are to determine whether serum cytokines differ in midlife and peri-/ postmenopausal women with schizophrenia compared to similarly matched healthy control women and to determine if serum cytokines are correlated with cognitive function differently in these groups.
Methods: Fourteen midlife (30- to 70-year-old) female patients with DSM-IV diagnosis of schizophrenia or schizoaffective disorder and 13 midlife healthy controls were analyzed for this study. Ten of the midlife patients and 8 of the midlife controls met the criteria for perimenopausal or postmenopausal reproductive stage, as defined by Study of Women’s Health Across the Nation (SWAN). Cytokines were collected from serum blood draws and analyzed at the Cytokine Core Lab at University of Maryland, Baltimore. The RBANS, HVLT-R, and UPSA were performed to measure attention, memory, and social performance.
Results: The results demonstrate a nonsignificant difference between interferon γ levels in women with schizophrenia compared to controls both in the midlife and peri/ postmenopausal groups, but this cytokine does appear to correlate with cognitive abilities differently in these groups. There were several significant negative correlations between interferon γ and cognition in midlife and peri-/ postmenopausal patients with schizophrenia (P < .05) and none in the peri-/ postmenopausal control group. The negative correlations between interferon γ and cognition in patients with schizophrenia suggest that inflammation may play a role in cognitive function in women with schizophrenia but not in healthy controls.
Conclusion: This study provides additional evidence that interferon γ may be associated with cognition in patients with schizophrenia, possibly through its role as an inducer of indoleamine-2, 3-dioxygenase (IDO) in the kynurenine pathway, a pathway of interest in schizophrenia. The results also contribute to the knowledge of schizophrenia in midlife and menopausal women, an understudied population likely differing from males.