Nx4 ameliorated peripheral and central stress-induced changes at resting state - A post hoc analysis of a randomized controlled trial

Abstract

Psychosocial stress provokes restlessness and perpetuates anxiety states, which may subsequently lead to major psychiatric disorders. Momentary adaptive responses to psychosocial stress can be reflected by electrophysiological (electroencephalogram: EEG) and physiological (heart rate variability: HRV) signals. A recent double-blind, placebo-controlled, crossover trial (NEURIM, NCT02602275) investigated the stress-reducing effects of Neurexan (Nx4) on neurophysiological and physiological changes in response to acute psychosocial stressors. This post hoc analysis aims to explore the stress-reducing effect of Nx4 on peripheral physiological (HRV) and central electrophysiological (EEG) levels at resting state. Thirty-nine healthy male participants received a single dose of Nx4 before exposure to a psychosocial stress paradigm. EEG and photoplethysmogram (PPG) data were acquired before and after psychosocial stress exposure induced by the ScanSTRESS task. Stress responsivity under placebo and Nx4 were assessed by HRV parameters and EEG frequency power. Psychosocial stress induction led to changes (i) in various parameters of heart rate variability, including increased LF/HF ratio, increased Baevsky’s Stress Index, and reduced RMSSD. As well as (ii) to changes in EEG frequency power with increased alpha and decreased theta power, both indicating successful stress induction. Nx4 reduced the stress-induced changes on both peripheral physiological and central electrophysiological levels. In the current study, we showed that the Nx4 reduced the acute peripheral physiological and central electrophysiological stress responses to psychosocial challenges. We suggest Nx4 may be a significant means to buffer the bodily responses of daily life stress exposure.