Co-existence of clinical high-risk for psychosis and bipolar disorder: a multi-dimensional psychopathological analysis

BACKGROUND: While the clinical high-risk for psychosis (CHR-P) has been extensively studied and the clinical high-risk for bipolar disorder (CHR-BD) has gained increasing attention, overlapping symptoms-such as mood instability and subclinical psychotic features-complicate diagnostic boundaries. We aimed to investigate the psychopathological characteristics of high-risk individuals to address the feasibility of early-stage diagnostic differentiation. We hypothesized that CHR-P and CHR-BD could co-occur and that symptom structure would differ depending on overlap status. METHODS: We recruited 231 participants without formal psychiatric diagnoses from a prospective cohort established at the psychiatry clinic of Seoul National University Hospital. We identified CHR-P and CHR-BD using the Structured Interview for Psychosis-Risk Syndromes (SIPS) and the Bipolar Prodrome Symptom Interview and Scale (BPSS), respectively. Participants were classified into CHR-P-only, CHR-BD-only, and CHR-P/BD-overlap groups. Participants were then evaluated across multiple psychopathological domains, including delusional ideation, obsessive-compulsive symptoms, perceptual abnormalities, depressive and manic symptoms, and global clinical severity. Symptom severity, inter-domain correlations, and symptom network structures were analyzed and compared across groups. RESULTS: The overlap was substantial: among 158 individuals meeting CHR-P criteria, 106 (67.1%) also met CHR-BD criteria, and among 179 individuals meeting CHR-BD criteria, 106 (59.2%) also met CHR-P criteria. The subgroup distribution was 52 CHR-P-only, 73 CHR-BD-only, and 106 CHR-P/BD-overlap. Symptom structures differed by overlap status. CHR-P-only showed significantly greater social withdrawal compared to other groups. CHR-P/BD-overlap had more severe mood, delusional, obsessive-compulsive, and hallucinatory symptoms. Correlation analysis showed weaker interconnections among symptom domains in CHR-P-only. Network analysis revealed four fragmented communities in CHR-P-only, two tightly integrated communities in CHR-BD-only, and partial integration across three communities in CHR-P/BD-overlap. Central symptoms varied: paranoia in CHR-P-only; mood symptoms and obsessive thoughts in CHR-BD-only; mood symptoms and perceptual abnormalities with religious themes in CHR-P/BD-overlap. CONCLUSIONS: High-risk states for psychosis and bipolar disorder frequently co-occur, suggesting that early psychopathology extends beyond the prodrome of any single disorder. Distinct patterns of symptom networks across high-risk subgroups underscore the value of dimensional and spectrum-based approaches to early psychopathology.