Executive dysfunction and cognitive subgroups in a large sample of euthymic patients with bipolar disorder

Area of Science:

• Neuroscience
• Psychiatry
• Cognitive Psychology

Background:

• Bipolar disorder (BP) is linked to cognitive deficits, particularly executive dysfunction.
• Response inhibition is a key executive function implicated in BP.
• Significant heterogeneity exists in BP neurocognitive performance, necessitating data-driven subgroup analysis.

Purpose of the Study:

• To identify distinct neurocognitive subgroups in bipolar disorder using data-driven methods.
• To compare neurocognitive profiles of bipolar disorder patients and healthy controls.
• To investigate factors associated with cognitive impairment in bipolar disorder.

Main Methods:

• Latent class analysis applied to executive function data from 556 euthymic BP patients and 416 healthy controls.
• Comprehensive cognitive testing battery and clinical measures were utilized.
• Subgroups were defined based on performance across executive functions.

Main Results:

• Four neurocognitive subgroups were identified: one good performance, two moderate impairment (differing in response inhibition and reasoning), and one severe impairment.
• BP patients were overrepresented in the severe impairment cluster (27% vs. 5.3% in controls) and underrepresented in the good performance cluster.
• Lower education and older age predicted membership in impaired subgroups; antipsychotic use was lower in the good performance group.

Conclusions:

• Cognitive differences between BP and controls are primarily driven by a subgroup with severe, global deficits.
• There is substantial overlap in cognitive functioning between some BP patients and healthy individuals.
• Identifying neurocognitive subgroups is crucial for understanding bipolar disorder heterogeneity.