MedWire News: The neurocognitive performance of bipolar disorder patients is unaffected by medication use, says a team of researchers in findings that suggest that neurocognitive deficits form a part of the disorder.

It has been established in previous studies that neurocognitive performance deficits persist even in euthymic bipolar disorder patients. However, the impact of medication on performance is unclear.

To investigate further, Utpal Goswami, from the University of Delhi in India, and colleagues administered a series of neuropsychologic tests, assessing executive function, memory, and attention, to 44 patients with bipolar I disorder, of whom 22 were drug-free.

The team reports in the journal Acta Psychiatrica Scandinavica that, over the range of neuropsychologic tasks, there were no significant differences between patients receiving medication and those who were drug-free.

There was a small trend for patients receiving medication to perseverate less on the five-point test and to have better delayed recall than drug-free patients, but these differences were eliminated when controlling for residual mood symptoms.

Residual depressive symptoms were shown to be significantly correlated with poor performance on auditory–verbal memory items. Medicated patients had more severe illness than drug-free patients, but none of the differences on severity variables were significant.

“In this small study, medication, predominantly mood stabilizers, was found to have small to medium, but statistically insignificant, effect sizes on the neurocognitive test performance of euthymic bipolar disorder subjects when residual mood symptoms were controlled,” the team concludes.

In an accompanying editorial, Eduard Vieta, as invited guest editor, said: “The relative unimportance of medication on bipolar disorder-associated deficits indicates that one of the possible ways to treat and prevent the neurocognitive impact of recurrences could be early, intensive, continued pharmacologic treatment, addressed at tackling subthreshold depressive symptoms and the prevention of further episodes.

“Other potentially useful tools include psychoeducation and interventions aimed at reverting the cycle of allostatic load.”

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