Cognitive Functioning in Euthymic Bipolar Patients on Monotherapy with Novel Antipsychotics or Mood Stabilizers

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Bipolar disorder is frequently accompanied by cognitive dysfunction across multiple domains.
• Medication effects are a significant confounder in assessing cognitive deficits in bipolar disorder.
• The comparative cognitive profiles of bipolar patients on different maintenance medications remain understudied.

Purpose of the Study:

• To compare the cognitive profiles of bipolar disorder patients in remission on monotherapy with novel antipsychotics (AP), lithium carbonate (Li), or valproic acid (VPA).
• To investigate potential differences in cognitive function related to specific maintenance treatments in bipolar disorder.

Main Methods:

• Cognitive assessment of euthymic bipolar disorder patients on monotherapy (AP n=16, Li n=25, VPA n=26) and healthy controls (n=42).
• Utilized a cognitive battery including Wechsler Adult Intelligence Scale-Revised (WAIS-R), Wechsler Memory Scale (WMS), and Wisconsin Card Sorting Test (WCST).
• Statistical analyses controlled for age and clinical features where appropriate.

Main Results:

• All patient groups demonstrated poorer performance in working memory and verbal memory compared to controls.
• Lithium carbonate group showed significantly better working memory compared to the novel antipsychotics group.
• Verbal memory deficits were consistent across all patient groups, suggesting a link to the disorder itself.

Conclusions:

• Atypical antipsychotics may adversely affect working memory in bipolar disorder patients.
• Working memory impairment could be a state marker, while verbal memory impairment may represent a trait marker of bipolar disorder.
• Findings highlight medication-specific cognitive effects and suggest distinct cognitive markers for bipolar disorder.