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

Objective:  Although it is established that euthymic bipolar patients have neurocognitive deficits, the influence of medication on their cognitive performance is uncertain and requires investigation. Method:  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. Results:  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. Conclusion:  Medications did not have any significant influence on neurocognitive performance, suggesting that neurocognitive deficits are an integral part of bipolar disorder.