Efficacy of orally administered Silexan in patients with anxiety-related restlessness and disturbed sleep – A randomized, placebo-controlled trial

Abstract The anxiolytic effect of Silexan, a patented active substance with an essential oil produced from Lavandula angustifolia flowers, was investigated in patients with anxiety-related restlessness and disturbed sleep. 170 out-patients with a diagnosis of restlessness (ICD-10 R45.1), a Hamilton Anxiety Scale (HAMA) total score ≥18 points and ≥2 points for HAMA items ‘Tension’ and ‘Insomnia’ participated in this randomized, double-blind trial and received 80 mg Silexan or placebo once daily for 10 weeks. Patients with clinically important other psychiatric or neurological disorders potentially interfering with the assessment of treatment efficacy were excluded. Outcome variables were the HAMA as well as the Pittsburgh Sleep Quality Index (PSQI), the Zung Self-rating Anxiety Scale, a State Check inventory and the Clinical Global Impressions questionnaire. In the Silexan group the HAMA total score decreased from an average of 25.5±6.0 points at baseline to 13.7±7.0 points at treatment end, compared to a decrease from 26.5±6.1 to 16.9±9.8 for placebo, corresponding to decreases of 12.0 and 9.3 points (marginal means), respectively (group difference: p =0.03, ANCOVA with factor treatment and baseline value as covariate). In all outcome measures the treatment effect of Silexan was more pronounced than with placebo. According to the HAMA, 48.8% and 33.3% of the patients were responders (Silexan, placebo; reduction ≥50%; p =0.04) and 31.4% and 22.6% achieved remission (HAMA p =0.20). 33.7% (Silexan) and 35.7% (placebo) of the participants reported adverse events. The study confirms the calming and anxiolytic efficacy of Silexan.