Reduced contagious yawning in psychiatric disorders: a systematic review of potential social-cognitive mechanisms

Introduction

Contagious yawning has been proposed to reflect multiple aspects of social cognition, including empathy, emotional contagion, self-processing, Theory of Mind (ToM), and action observation mechanisms such as the human mirror neuron system (hMNS). However, its underlying mechanisms remain debated, with evidence suggesting additional roles for social attention, gaze allocation, social motivation, and neurobiological factors. This systematic review examined evidence for reduced contagious yawning in Autism Spectrum Disorder (ASD), schizophrenia-spectrum disorders, and psychopathic traits, and evaluated potential underlying mechanisms.