CT-optimal touch modulates alcohol-cue-elicited heart rate variability in alcohol use disorder patients during early abstinence: A randomized controlled study

Alcohol Use Disorder (AUD) is a chronic brain disorder associated with a high risk of relapse and a limited treatment efficacy. Relapses may occur even after long periods of abstinence and are often triggered by stress or cue induced alcohol craving. C-tactile afferents (CT) are cutaneous nerve fibers postulated to encode pleasant affective touch and known to modulate physiological stress responses. However, their translational potential has not yet been explored extensively in controlled clinical trials. This randomized controlled study aimed to investigate the potential of CT stimulation in modulating relapse predicting biomarkers, physiological cue-reactivity, and subjective alcohol craving in AUD patients in early abstinence. Twenty-one participants meeting DSM-5 criteria for mild to moderate AUD received CT-optimal touch or a non-CT-optimal control treatment while exposed to neutral, stress-inducing, and alcohol-related visual stimuli. The tactile treatment was provided with a robotic device, eliminating the social elements of touch. Heart rate variability (HRV), salivary cortisol, and subjective craving were assessed at the baseline, during and after the treatment and stimuli exposure. The results showed that CT-optimal touch significantly reduced alcohol-cue-elicited standard deviation of normal-to-normal intervals (SDNN) HRV compared to the control group, shifting the HRV reactivity to the direction known to indicate lower relapse susceptibility. Cortisol levels showed no significant differences between the groups, and subjective alcohol craving increased after alcohol cue exposure in both groups. This study found that CT-optimal touch modulates autonomic cue-reactivity in AUD patients, encouraging further research on the therapeutic potential of affective touch. Future research should explore the long-term effects and real-world clinical relevance of CT-optimal touch in alcohol relapse prevention.