Introduction: It is yet unknown whether valproate’s neuroprotective effects confer cognitive benefits. This is the first study in prospective design showing effects of valproate on neurocognitive functioning in bipolar disorder.
Methods: Twenty five drug free patients (9 euthymic, 9 manic and 7 depressive) were assessed with a large neurocognitive battery before and after six weeks of valproate montherapy in comparison to 23 sex, age and educationwise matched healthy controls who were assessed twice with a six week interval. Repeated measures ANOVA and Pearson correlation tests were used where necessary.
Results: Patients and controls did not differ in performance at both time points as shown by a nonsignificant group effect for all domains tested. However, the time effects were significant for Rey Auditory Verbal Learning Test total (p= 0.0001) and long-delay free recall scores (p= 0.009), Continous Performance Test prime scores (p= 0.02), Wisconsin Card Sorting Test category (p= 0.03), error (p= 0.03) and perseverative error (p= 0.006) scores, and Visual Reproduction Test immediate scores (p= 0.03), indicating an improvement for both groups over time. The subgroup analysis did not reveal any significant difference between manic, depressed or euthymic patients. The change in cognitive and CGI scores were not correlated.
Conclusion: Similar improvement in certain cognitive domains in patients and controls over time is indicative of an intact learning ability in both groups. Relatively short term valproate monotherapy doesn’t seem to show any deteriorating effect on cognitive functioning in bipolar patients. The finding may be due to valproate’s neuroprotective effect.