Cognitive and Executive Dysfunction: Effect of Age and Medications

Issues about cognitive or executive dysfunction as well as general matters of intellectual deterioration with bipolar disorder continue to interest me. I am adding some fairly recent articles to the blog pertaining to such phenomena. Peter J. Dorsen, M.D., LADC

Neurocognition in bipolar disorders—a closer look at comorbidities and medications. Bulanza-Martinez V et al Eur. J Pharmacol. 2010 Jan 10; 626(1): 87-96.
Their research is of neuropsychological study in bipolar disorder associated with persistent neurocognitive impairments EVEN during periods of euthymia in the broad domains of attention, verbal memory, and executive function. They also showed that there was a poorer functional outcome among bipolar disorder patients. Cognitive dysfunction is gene-environmental, drug–induced cognitive adverse effects ie there are confounders. It is important to look at the contribution medications plus medical and psychiatric co-morbid conditions have on bipolar disorder.

The longitudinal course of cognition in older adults with bipolar disorder Gildengers AG et al Bipolar Disorder. 2009 Nov; 11(7): 744-52.
“…elders with bipolar disorder (BD) may be at increased risk for dementia…”
Findings: Subjects with BD performed significantly worse on the Dementia Rating Scale (DRS) compared to mentally healthy comparators. In their study, “older adults with BD had more cognitive dysfunction and more rapid cognitive decline than expected given their age and education.”
The consequences of such decline was decreased independence and increased reliance on family and community supports with EVEN potential placement in assisted living facilities.

Cognitive features in euthymic bipolar patients in old age Delaloye C et al Bipolar Disord. 2009 Nov; 11(7): 735-43. Their conclusion relates to the notion that cognitive changes observed in older BD patients is similar to that observed in younger BD cohorts. However, issues relating to processing speed and episodic memory are two CORE DEFICITS that appear to differ in elderly BD patients.

Identifying and treating cognitive impairment in bipolar disorder Bipolar Disord. 2009 Jun; 11 Suppl 2:123-137. Goldberg JF, Chengappa KN. These investigators found that circumscribed cognitive deficits may be both iatrogenic and intrinsic to bipolar disorder. They concluded that cognitive deficits involving attention, executive function, and verbal memory are evident across ALL PHASES OF BIPOLAR DISORDER.

Clinical predictors of functional outcome of bipolar patients in remission Rosa A et al Bipolar Disorders VII(4):401-409, showed that 60% of 71 euthymic patients had overall functional impairment.Bipolar patients showed a worse functioning in all areas of the Functioning Assessment Short test (FAST). Previous mixed episodes, current subclinical depressive symptoms, previous hospitalizations, and older age were identified as significant predictors of functional impairment.

In the J Clin Psychiatry. 2009 Jul; 70(7):1017-23., Martinez-Aram A et al emphasized : “a close relationship between poor treatment adherence and cognitive impairment, but the causal inferences of these findings are uncertain.” They conclude that such poor treatment adherence may worsen the course of bipolar disorder and so indirectly worsen cognitive performance (thus, more severe illness).

A comparison of cognitive functioning in medicated and non medicated subjects with bipolar depression Holmes MK et al Bipolar Disord. 2009 Nov; 10(7): 806-15. This study demonstrated deficits in affective processing in the medicated group. They saw more errors in the “happy” conditions, indicating a potential attentional bias in subjects with bipolar depression on mood-stabilizing medications.
Excellent quote: “The present study also implicates impairment in sustained attention for medicated subjects with bipolar disorder PARTICULARLY those with bipolar II.