Cognitive performance in bipolar disorder: Comparison between individuals with and without suicide attempts and healthy controls

Introduction

Bipolar disorder (BD) presents an elevated risk of suicide. One hypothesis for this is that cognitive impairments contribute to suicidal behavior. However, the relationship between cognition and suicidal behavior in BD remains unclear.

Objective

To compare cognitive performance in individuals with BD with previous suicide attempts vs no attempt vs healthy controls (HC).

Methods

We included 306 participants: 101 individuals with BD (49 with previous suicide attempts and 52 without attempts) and 205 HC. Participants underwent a clinical interview and neuropsychological evaluation. We assessed cognitive performance in social cognition, episodic verbal memory, working memory, processing speed, executive functioning, sustained attention, and intelligence. Afterwards, individuals with BD were separated between groups with and without suicide attempts. We then compared cognitive performance and clinical characteritics between groups.

Results

Individuals with BD who attempted suicide had more hospitalizations, higher prevalence of psychiatric family history, and overall greater functional impairment. Regarding cognition, HC outperformed both BD groups, with the exception of social cognition and Stroop Color-Word and interference weighted score. However, there were no significant differences in cognitive performance among both BD groups.

Limitations

Cross-sectional design and dichotomization between suicide attempt vs. no attempt

Conclusions

BD with previous suicide attempt present worse clinical outcomes and higher illness severity. Nevertheless, there were no cognitive differences among individuals with BD with and without suicide attempts. Both BD groups may share a vulnerability for cognitive impairment, but not for clinical and functional outcomes. Our results point to significant heterogeneity among clinical and functioning areas of BD.