The effects of cognitive reserve on predicting and moderating the cognitive and psychosocial functioning of patients with bipolar disorder

Background: Cognitive reserve (CR) reflects the resilience of the brain to cope with neuropathological changes and minimize clinical manifestations. In the present study, we explore the association between CR and cognitive and psychosocial functioning, and examined the potential moderating role of CR in patients with bipolar disorder (BD). Methods: One hundred and twenty-five outpatients with BD type I and sixty healthy individuals were recruited. All participants were assessed with a neuropsychological battery examining attention and processing speed, working memory, visual memory and executive functioning, the Global Assessment of Functioning scale and the Cognitive Complaints in Bipolar Disorder Rating Assessment. Proxies for cognitive reserve included premorbid intelligence and educational level. Results: Patients with bipolar disorder presented with worse cognitive performance and psychosocial functioning than healthy controls. Multiple regression models revealed that educational level negatively associated with all assessed domain-specific cognition scores and premorbid intelligence predicted attention and processing speed and psychosocial functioning. Notably, premorbid intelligence significantly moderated the associations between the number of episodes (total, hypo/manic and depressed) and neurocognitive functioning, and the educational level also moderated the relationships between the numbers of hypo/manic and total episodes and subjective cognitive functioning. Conclusions: Cognitive reserve contributes to functional outcomes in patients with BD and may emerge as a key factor contributing to the course and prognosis of patients with BD. In the future, cognitive reserve must be considered in both research and clinical interventions related to bipolar disorder.