The relationship of bipolar disorder lifetime duration and vascular burden to cognition in older adults

Abstract

Objectives: We describe the cognitive function of older adults presenting with bipolar disorder (BD) and mania and examine whether longer lifetime duration of BD is associated with greater cognitive dysfunction. We also examine whether there are negative, synergistic effects between lifetime duration of BD and vascular disease burden on cognition.

Methods: A total of 87 nondemented individuals with bipolar I disorder, age 60 years and older, experiencing manic, hypomanic, or mixed episodes, were assessed with the Dementia Rating Scale (DRS) and the Framingham Stroke Risk Profile (FSRP) as a measure of vascular disease burden.

Results: Subjects had a mean (SD) age of 68.7 (7.1) years and 13.6 (3.1) years of education; 50.6% (n = 44) were females, 89.7% (n = 78) were white, and 10.3% (n = 9) were black. They presented with overall and domain-specific cognitive impairment in memory, visuospatial ability, and executive function compared to age-adjusted norms. Lifetime duration of BD was not related to DRS total score, any other subscale scores, or vascular disease burden. FSRP scores were related to the DRS memory subscale scores, but not total scores or any other domain scores. A negative interactive effect between lifetime duration of BD and FSRP was only observed with the DRS construction subscale.

Conclusions: In this study, lifetime duration of BD had no significant relationship with overall cognitive function in older nondemented adults. Greater vascular disease burden was associated with worse memory function. There was no synergistic relationship between lifetime duration of BD and vascular disease burden on overall cognition function. Addressing vascular disease, especially early in the course of BD, may mitigate cognitive impairment in older age.

Figure 1

Overall model of factors affecting cognitive function in BD. Multiple mechanisms are likely involved in the development of cognitive dysfunction in BD, including A) BD-Specific Factors, B) BD Co-Morbidity Factors, C) Aging, and D) Protective Factors. Mechanisms are likely intercorrelated. All potential interactions are not depicted.