Older bipolar patients have worse cognition than depressed peers
MedWire News: Elderly adults with bipolar disorder have poorer cognitive function than their peers with major depressive disorder (MDD), study results suggest.
"In late life, BD and MDD are associated with cognitive dysfunction even when patients are euthymic," observe Meryl Butters (University of Pittsburgh School of Medicine, Pennsylvania, USA) and team.
But they add: "Whether BD and MDD have similar or different cognitive profiles and levels of impairment in older age is not clear."
To investigate further, the researchers studied 43 euthymic BD patients (mean age 74.0 years), 122 euthymic MDD patients (mean age 74.3 years), and 92 mentally healthy controls (mean age 74.0 years).
The team used a comprehensive test battery to assess the participants on four cognitive domains: delayed memory, information processing speed/executive function, language, and visuomotor. Composite factor scores for these domains were compared between the mood disorder patients and controls, and between BD and MDD patients.
The mood disorder patients were also assessed for cognitive-instrumental activities of daily living using the Performance Assessment of Self-care Skills (PASS).
The researchers found that BD and MDD patients had significantly worse composite scores on all cognitive domains compared with controls, and were particularly impaired in the domain of information processing speed/executive function.
Among the mood disorder patients, those with BD had poorer performance in all cognitive domains compared with MDD patients, after adjustment for age, education, and vascular burden.
Specifically, the least square means for the composite factor scores in BD and MDD patients regarding delayed memory, information processing speed/executive function, language, and visuomotor domains were -0.63 versus -0.16, -1.14 versus -0.35, -0.82 versus -0.16, and -0.90 versus -0.21, respectively. Controls had a score of 0 for each domain.
There were no significant differences between BD and MDD patients regarding PASS scores, however.
Butters and team conclude in the journal Bipolar Disorder: "In older age, patients with BD have worse overall cognitive function than patients with MDD.
"Our findings suggest that factors intrinsic to BD appear to be related to cognitive deterioration and support the understanding that BD is associated with cognitive decline."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2012
By Mark Cowen