The neurocognitive performance of drug-free and medicated euthymic bipolar patients do not differ

Although it is established that euthymic bipolar patients have neurocognitive deficits, the influence of medication on their cognitive performance is uncertain and requires investigation.

Neuropsychological tests of executive function, memory and attention were performed on 44 prospectively verified, euthymic bipolar I patients, 22 of whom were drug-free. Residual mood symptom effects were controlled statistically using ancova.

Drug-free and medicated patients differed only in delayed verbal recall (Rey AVLT list A7, drug-free > medicated), and perseverations during the five-point test (drug-free > medicated). When residual mood symptoms were controlled statistically, differences between drug-free and medicated subjects became insignificant. Medication effect sizes were modest. Significant correlations were found between residual depression scores and measures of verbal learning.

Medications did not have any significant influence on neurocognitive performance, suggesting that neurocognitive deficits are an integral part of bipolar disorder.