Interactions Between Depression, Autonomic Dysfunction, Inhibitory Control and Reaction Time: Insights From Heart Rate Variability During Continuous Performance Test.

Objective: This study investigates the relationship between depression, autonomic dysfunction, inhibitory control (IC), and reaction time by analyzing heart rate variability (HRV) during a cognitive task.

Methods: A total of 29 healthy males and 25 males diagnosed with depression (aged 20-35 years) participated. HRV data were recorded during the Conners Continuous Performance Test-II (CCPT-II) in each group. HRV parameters, including mean RR intervals, standard deviation of normal-to-normal heartbeats (SDNN), low-frequency power with logarithm (lnLF), and high-frequency power with logarithm (lnHF), were analyzed and correlated with IC (d') and reaction time.

Results: The depression group exhibited significantly lower lnHF values compared to the healthy group. SDNN and lnLF decreased in both groups during CCPT-II. In the healthy group, d' correlated significantly with SDNN, lnLF, and lnHF at t14 and across the test duration. However, in the depression group, only RR intervals correlated with d'. A significant correlation between reaction time and HRV was noted at t14 in the healthy group, suggesting autonomic nervous system (ANS) involvement in cognitive performance.

Conclusion: Reaction time in healthy individuals correlated with ANS function during later stages of CCPT-II, whereas depression disrupted this association. The lower d' in the depression group was not due to a speed-accuracy trade-off but rather a more pronounced neural network impairment. These findings suggest that depression impairs both IC and autonomic regulation.