title: Specific expectancies are associated with symptomatic outcomes and side effect burden in a trial of chamomile extract for generalized anxiety disorder.
abstract: Patient expectancies are hypothesized to contribute to the efficacy and side effects of psychiatric treatments, but little research has investigated this hypothesis in the context of psychopharmacological therapies for anxiety. We prospectively investigated whether expectancies predicted efficacy and adverse events in oral therapy for Generalized Anxiety Disorder (GAD), controlling for confounding patient characteristics correlating with outcomes.
  
  
  
  Expectancies regarding treatment efficacy and side effects were assessed at baseline of an eight week open-label phase of a trial of chamomile for Generalized Anxiety Disorder (GAD). The primary outcome was patient-reported GAD-7 scores, with clinical response and treatment-emergent side-effects as secondary outcomes. Expectancies were used to predict symptomatic and side-effect outcomes.
  
  
  
  Very few baseline patient characteristics predicted either type of expectancy. Controlling for a patient's predicted recovery based on their baseline characteristics, higher efficacy expectancies at baseline predicted greater change on the GAD-7 (adjusted β = -0.19, p = 0.011). Efficacy expectancies also predicted a higher likelihood of attaining clinical response (adjusted odds ratio = 1.69, p = 0.002). Patients with higher side effect expectancies reported more side effects (adjusted log expected count = 0.26, p = 0.038). Efficacy expectancies were unrelated to side effect reports (log expected count = -0.05, p = 0.680), and side effect expectancies were unrelated to treatment efficacy (β = 0.08, p = 0.306).
  
  
  
  Patients entering chamomile treatment for GAD with more favorable self-generated expectancies for the treatment experience greater improvement and fewer adverse events. Aligning patient expectancies with treatment selections may optimize outcomes.
  
  
  
  Trial Number NCT01072344 at ClinicalTrials.gov.
authors.affiliation: Department of Psychology, School of Arts and Sciences at the University of Pennsylvania, PA, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Keefe
authors.affiliation: Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, PA, USA.
authors.forename: Jay
authors.initials: J
authors.lastname: Amsterdam
authors.affiliation: Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, PA, USA.
authors.forename: Qing S
authors.initials: QS
authors.lastname: Li
authors.affiliation: Department of Psychiatry, Perelman School of Medicine at the University of Pennsylvania, PA, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Soeller
authors.affiliation: Department of Psychology, School of Arts and Sciences at the University of Pennsylvania, PA, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: DeRubeis
authors.affiliation: Memorial Sloan-Kettering Cancer Center, NY, USA. Electronic address: maoj@mskcc.org.
authors.forename: Jun J
authors.initials: JJ
authors.lastname: Mao
mesh_terms: D014151:Anti-Anxiety Agents / Q000009:adverse effects / Q000627:therapeutic use*; D059031:Anticipation, Psychological; D001008:Anxiety Disorders / Q000188:drug therapy* / Q000523:psychology*; D020843:Chamomile; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D008517:Phytotherapy / Q000009:adverse effects; D010936:Plant Extracts / Q000009:adverse effects / Q000627:therapeutic use*; D011569:Psychiatric Status Rating Scales; D016896:Treatment Outcome
chemical_list: D014151:Anti-Anxiety Agents; D010936:Plant Extracts
keywords: Anxiety; Efficacy; Expectancy; Nocebo; Placebo