Sleep duration phenotypes in generalized anxiety disorder based on objective sleep monitoring and heart rate variability

To explore the autonomic nervous function characteristics of generalized anxiety disorder (GAD) patients with different sleep duration subtypes and clarify the association between sleep phenotypes and autonomic nervous dysfunction. Methods: This study included 128 patients with GAD. Objective sleep was assessed via a sleep monitor. Subjective measures included the Pittsburgh Sleep Quality Index (PSQI), Self-Rating Anxiety Scale(SAS), Self-Rating Depression Scale(SDS), and Suicide Risk Factor Assessment Scale(SRFAS). Based on objective total sleep time (TST), participants were stratified into an objective near-normal sleep duration group (GAD-NST, TST ≥ 6 h, n = 60) and an objective short sleep duration group (GAD-SST, TST < 6 h, n = 68). Results: Compared with the GAD-NST group, the GAD-SST group exhibited significantly elevated low-frequency power, normalized low-frequency power, and LF/HF ratio, alongside reduced normalized high-frequency power (all p < 0.05); In terms of objective sleep parameters, the GAD-SST subgroup had shorter total sleep time and lower sleep efficiency. Furthermore, both duration and proportion of light sleep and rapid eye movement(REM) sleep were significantly reduced in this subgroup (all p < 0.05). Compared with the GAD-NST group, the GAD-SST group exhibited significantly higher percentages of deep sleep, number of awakenings, wake after sleep onset (WASO), and sleep latency (all p < 0.05). Conclusion: Objective short sleep duration identifies a distinct GAD phenotype.This phenotype is characterized by greater autonomic imbalance and more severe disruption of sleep architecture. Incorporating objective sleep and heart rate variability(HRV) assessments may improve GAD phenotyping and guide individualized management.