Increased rates of white matter hyperintensities in late-onset bipolar disorder

Area of Science:

• Neuroimaging and Psychiatry
• Cerebrovascular Disease and Mental Health

Background:

• Late-onset depression is associated with increased white matter hyperintensities (WMH), suggesting vascular mechanisms in late-onset mood disorders.
• Emerging evidence links late-onset bipolar disorder (LO-BD) to cerebrovascular risk factors, but neuroimaging data remain limited.
• Understanding WMH in LO-BD is crucial for differentiating its pathophysiology from early-onset bipolar disorder (EO-BD).

Purpose of the Study:

• To investigate the association between white matter hyperintensities (WMH) and late-onset bipolar disorder (LO-BD).
• To compare WMH prevalence in LO-BD patients versus early-onset BD (EO-BD) patients and elderly healthy volunteers.
• To explore neuroimaging evidence for vascular contributions to LO-BD.

Main Methods:

• Acquisition of T2-weighted MRI data from three groups: LO-BD (n=10), EO-BD (n=49), and healthy controls (n=24).
• Assessment of white matter hyperintensities (WMH) using the Scheltens scale.
• Statistical comparison of WMH rates and scores between groups, with adjustments for age.

Main Results:

• Late-onset bipolar disorder (LO-BD) patients exhibited a significantly higher prevalence of WMH in the deep parietal region and basal ganglia compared to EO-BD and healthy controls.
• After adjusting for age, LO-BD patients showed more severe WMH scores in deep frontal and parietal regions, and the putamen.
• These findings indicate a distinct pattern of WMH in LO-BD.

Conclusions:

• The study provides empirical support for a link between vascular risk factors and late-onset bipolar disorder (LO-BD).
• The observed WMH patterns may help distinguish the pathophysiology of LO-BD from early-onset bipolar disorder (EO-BD).
• Larger sample studies are needed to confirm these findings and elucidate the role of vascular mechanisms in LO-BD.