Relationship of suicidal behavior with impulsivity and HEART rate variability in mood disorders

Objectives: Suicide is one of the leading preventable causes of death worldwide. Although many risk factors for suicidal behavior have been identified, it is still not possible to predict suicidal behavior. Studies have suggested that features such as impulsivity and response inhibition are associated with suicidal behavior. Heart rate variability (HRV) is considered an indicator of the inhibitory effects of the prefrontal cortex. We aimed to examine the relationship between impulsivity and HRV in suicidal behavior. Patients and Methods: A total of 30 patients with mood disorders who were hospitalized because of suicide risk were included in the study. Participants were divided into two groups according to whether they had only suicidal ideation (SI) or suicide attempt (SA) in the last 15 days. Go-NoGo test was used to measure response inhibition. HRV of the participants were measured at rest, during, and after the test. Go-NoGo test results and time- and frequency-domain measures of HRV were compared between SI and SA groups. Results: The groups were similar in terms of sociodemographic characteristics, but the mean age of the SA group was lower. The groups did not differ in severity of depression, anxiety levels, childhood traumas, impulsivity, and aggression scores. Results of the Go-NoGo test were not different between the two groups. Similarly, no difference was found between the groups in terms of resting HF-HRV, HF-HRV reactivity, or other measured HRV parameters. In additional analyzes, the LF/HF measurements differed according to the test status in the SI group, this variability was not found in the SA group. Conclusions: HRV measures did not differ between those with only suicidal ideation and those with a recent suicide attempt in patients with current mood disorders, either at rest or during the response inhibition task. However, sympathovagal response might be blunted in the response inhibition task in those who have recently attempted suicide.