title: Effects of Silexan on the serotonin-1A receptor and microstructure of the human brain: a randomized, placebo-controlled, double-blind, cross-over study with molecular and structural neuroimaging.
abstract: BACKGROUND
  Recently, Silexan, a patented active substance comprised of an essential oil produced from Lavandula angustifolia flowers, has been authorized in Germany as a medicinal product for the treatment of states of restlessness related to anxious mood. Its efficacy has been shown in several forms of anxiety disorders. Findings from preclinical and clinical studies attribute a major role to the serotonin-1A receptor in the pathogenesis and treatment of anxiety.
  
  
  METHODS
  To elucidate the effect of Silexan on serotonin-1A receptor binding, 17 healthy men underwent 2 positron emission tomography measurements using the radioligand [carbonyl-(11)C]WAY-100635 following the daily intake of 160 mg Silexan or placebo for a minimum of 8 weeks (randomized, double-blind, cross-over design). Additionally, structural magnetic resonance imaging and voxel-based morphometry analysis was performed to determine potential effects on gray matter microstructure.
  
  
  RESULTS
  Serotonin-1A receptor binding potential was shown to be significantly reduced following the intake of Silexan compared with placebo in 2 large clusters encompassing the temporal gyrus, the fusiform gyrus and the hippocampus on one hand as well as the insula and anterior cingulate cortex on the other hand. No effects of Silexan on gray matter volume could be detected in this investigation.
  
  
  CONCLUSIONS
  This positron emission tomography study proposes an involvement of the serotonin-1A receptor in the anxiolytic effects of Silexan. The study was registered in the International Standard Randomized Controlled Trial Number Register as ISRCTN30885829 (http://www.controlled-trials.com/isrctn/).
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Pia
authors.initials: P
authors.lastname: Baldinger
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Anna S
authors.initials: AS
authors.lastname: Höflich
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Mitterhauser
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hahn
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Christina
authors.initials: C
authors.lastname: Rami-Mark
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Marie
authors.initials: M
authors.lastname: Spies
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wadsak
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria.
authors.forename: Rupert
authors.initials: R
authors.lastname: Lanzenberger
authors.affiliation: Department of Psychiatry and Psychotherapy (Drs Baldinger, Höflich, Hahn, Spies, Lanzenberger and Kasper), Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine (Drs Mitterhauser, Rami-Mark and Wadsak), Medical University of Vienna, Austria. sci-biolpsy@meduniwien.ac.at.
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kasper
mesh_terms: D000328:Adult; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001921:Brain / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D002250:Carbon Radioisotopes; D018592:Cross-Over Studies; D004311:Double-Blind Method; D066128:Gray Matter / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D027523:Lavandula; D008279:Magnetic Resonance Imaging; D008297:Male; D009822:Oils, Volatile / Q000494:pharmacology*; D010879:Piperazines; D010938:Plant Oils / Q000494:pharmacology*; D049268:Positron-Emission Tomography; D011725:Pyridines; D019275:Radiopharmaceuticals; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism*; D055815:Young Adult
chemical_list: D014151:Anti-Anxiety Agents; D002250:Carbon Radioisotopes; D009822:Oils, Volatile; D010879:Piperazines; D010938:Plant Oils; D011725:Pyridines; D019275:Radiopharmaceuticals; D044282:Receptor, Serotonin, 5-HT1A; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; C045718:lavender oil
keywords: Silexan; gray matter volume; lavender oil; positron emission tomography; serotonin-1A receptor; structural magnetic resonance imaging