Higher blood pressure is associated with lower cerebral blood flow in youth with bipolar disorder.

BACKGROUND: Bipolar disorder (BD) is associated with differences in cerebral blood flow (CBF), a measure fundamental to brain health. Blood pressure (BP) is elevated in BD, and associated with CBF. Research integrating these themes, particularly in youth, remains limited. METHODS: Participants included 144 youth aged 13-20 (76 BD, 68 healthy controls [HC]). T1-weighted and arterial spin labeling (ASL) MRI were collected, alongside diastolic (DBP) and systolic (SBP) BP. CBF maps were calculated from ASL. Region of interest (ROI) and voxel-wise analyses examined BP in relation to CBF, controlling for age and sex. ROIs included anterior cingulate cortex, prefrontal cortex (PFC), and insular cortex. RESULTS: In the overall sample, higher DBP was associated with lower CBF in each ROI, and higher SBP was associated with lower PFC CBF. Within BD, higher DBP and SBP were associated with lower CBF in all ROIs. There were no associations within the HC group. Voxel-wise analyses showed that higher BP was associated with lower CBF across the cortex, particularly for DBP and within the BD group. Diagnosis-interaction effects for DBP revealed that higher DBP was more strongly associated with lower CBF in BD vs. HC in the frontal pole and bilateral frontal orbital cortex. CONCLUSION: Higher BP in youth is associated with lower CBF, a relationship more pronounced in those with BD than in HC. This suggests elevated BP may contribute to neurovascular dysfunction in youth with BD, potentially affecting cognition and emotion. Further research is needed to characterize the potential underlying mechanisms.