Effect of high-frequency stellate ganglion block on sleep and affective symptoms in insomnia disorder: a prospective pilot study

Insomnia disorder imposes substantial health burdens, while current pharmacotherapies risk adverse effects and cognitive behavioral therapy face implementation barriers. Stellate ganglion block (SGB) modulates autonomic function and sleep architecture but lacks evidence for optimized protocols. This pilot study evaluates the feasibility and preliminary clinical outcomes of a high-frequency SGB protocol for improving sleep, anxiety, and depression in insomnia disorder. A single-center, prospective single-arm trial enrolled 72 patients diagnosed with insomnia disorder according to ICSD-3 criteria. Participants received daily ultrasound-guided SGB (0.8% lidocaine, 3 ml) unilaterally for 10 consecutive days. Outcomes included Pittsburgh Sleep Quality Index (PSQI), Generalized Anxiety Disorder-7 (GAD-7), and Patient Health Questionnaire-9 (PHQ-9) scores assessed at baseline (T1), immediately post-intervention (T2), and at 4-week (T3) and 12-week (T4) follow-up. Statistical analysis used repeated-measures ANOVA. The mean PSQI score improved from 15.35 ± 2.39 at baseline to 10.59 ± 3.23 post-intervention (mean reduction 4.76, 95% CI 4.04, 5.49, P < 0.001), exceeding the minimal clinically important difference (MCID) of 3 points. This improvement was sustained at 12 weeks (mean reduction 4.08, 95% CI 3.32, 4.85). Anxiety (GAD-7: baseline 7.47 ± 4.57) and depression (PHQ-9: baseline 9.07 ± 5.72) scores showed statistically significant reductions post-treatment (GAD-7: T2-T4 P < 0.05; PHQ-9: T2-T4 P < 0.05). However, the magnitude of improvement did not reach established MCID (4 points for GAD-7, 5 points for PHQ-9), with mean reductions ranging from 0.99 to 2.18 points for GAD-7 and 1.72 to 2.04 points for PHQ-9. This suggests that while statistically detectable, the clinical relevance of affective symptom improvements may be limited, particularly given the relatively mild baseline symptom severity. This pilot study demonstrates that a high-frequency SGB protocol is feasible to implement in patients with insomnia disorder. Within-group improvements in sleep quality that exceeded the MCID were observed and sustained through 12-week follow-up. However, due to the uncontrolled single-arm design, these results should be interpreted as hypothesis-generating rather than confirmatory. The observed improvements may be attributable to placebo effects, natural history, or regression to the mean. These findings provide effect size estimates to inform the design of future randomized sham-controlled trials, which are necessary to establish causal efficacy. This study was registered on the Chinese Clinical Trial Registry on March 19th, 2025 (Registration No.: ChiCTR2500099219).