Abstract
BACKGROUND: The identification of early warning signs is of great importance for identifying individuals at risk for mental disorders. Especially in the case of bipolar disorder, these research endeavours are imperative considering that the frequently delayed diagnoses and longer illness duration are associated with symptom exacerbation and lower recovery rates. AIMS: To multimodally investigate associations between hypomanic personality traits and altered social affect and social cognition to probe their role as early warning signs of bipolar disorder. METHOD: In a community sample (n = 140; 50.71% female), we investigated associations between hypomanic personality traits and both behavioural and neural activity measures of empathy and theory of mind (ToM) based on data from a functional magnetic resonance imaging paradigm. RESULTS: Although analyses revealed no significant associations between behavioural or neural correlates of empathy and hypomanic personality traits, these traits were significantly associated with elevated ToM-related neural activity in the anterior rostral medial prefrontal cortex and anterior cingulate cortex. These neural activation differences were not accompanied by differences in behavioural ToM performance, suggesting more intense recruitment of task-relevant brain regions but unaffected behavioural outcomes. CONCLUSIONS: Our findings indicate hypomanic personality traits to be positively associated with ToM-related neural activity but not with behavioural ToM performance. Prospectively, our study contributes to driving towards a more comprehensive and potentially neurobiologically grounded phenotype of bipolar disorder risk that contributes to a more differential understanding of risk and resilience mechanisms.