Relationship Between Serum Uric Acid Levels and Cognitive Functions in Bipolar Disorder

Background: Many studies have shown that cognitive impairment persists during the remission period in bipolar disorder type 1 (BPD1). Uric acid, the end product of purine catabolism, is a natural antioxidant. The purinergic system has a role in the regulation of mood, sleep, energy, cognitive function and behaviour. Previous studies have indicated that a malfunction of the purinergic system might have an impact on the pathophysiology of BPD1. In this study, we aimed to compare differences in cognitive functions and serum urate levels between patients with BPD1 and healthy controls (HC) and to evaluate the relationship between serum uric acid levels and cognitive functions in the patient group.

Methods: This study included 75 euthymic patients with BPD1 and 75 healthy age – and sex-matched individuals. All participants completed a sociodemographic form, the Beck Anxiety Inventory (BAI), the Beck Depression Inventory (BDI) and the Montreal Cognitive Assessment scale (MoCA). All also underwent a neuropsychometric battery and measurement of blood serum uric acid levels. The researchers conducted clinical interviews using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) Structured Clinical Interview for DSM Disorders (SCID-I) and obtained Young Mania Rating Scale (YMRS) scores for the patients; the HC group was investigated using the non-patient version of the SCID.

Results: In all neurocognitive domains, patients demonstrated worse performance than the healthy controls (p<0.05). Serum uric acid levels were significantly lower in the BPD1 group than in the HC group (p<0.05) and highlighted a statistically significant effect for the differentiation of BPD1 from HC in the regression analysis (p<0.05). Participants displayed no statistically significant correlation between uric acid levels and the neurocognitive domains of attention, executive functions and visual memory (p>0.05). However, a statistically significant negative correlation was observable between uric acid levels and the neurocognitive domain of verbal memory (p<0.05).

Conclusion: Study results revealed a relationship between the rise in serum uric acid levels and impairment in verbal memory functions in patients with BPD1. Our study is the first to report the relationship between serum uric acid levels and all areas of cognitive functions, including executive functions, verbal and visual memory and attention, as assessed using neurocognitive batteries in patients with euthymic BPD1. Uric acid may therefore present a target in the treatment of BPD1, especially in the presence of various cognitive dysfunctions.

To cite this article: Uluyol Bas O, Onur Sahmelikoglu O, Ajda Ekinci A, Guclu O. Relationship Between Serum Uric Acid Levels and Cognitive Functions in Bipolar Disorder. Psychiatry and Clinical Psychopharmacology 2020;30(2):165-174