Long-Term Chamomile Therapy of Generalized Anxiety Disorder

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DESCRIPTION (provided by applicant): Anxiety disorders are among the most common psychiatric conditions. They affect up to 25% of the US adult population. Generalized anxiety disorder (GAD) is a chronic, recurrent form of the disorder. Although benzodiazepines and serotonin reuptake inhibitors have become the mainstay therapy of GAD, these drugs are often associated with unwanted side effects, habituation, and withdrawal symptoms. Many individuals decline using conventional drug therapy for financial, cultural, or personal reasons such as the stigma of mental illness. As a result, many individuals will seek alternative therapy for their anxiety symptoms. The identification of effective alternative therapies for GAD would be of particular relevance. Among alternative therapies for anxiety, chamomile has been used as a traditional herbal medicine for its calming effect. It is well tolerated and demonstrates pharmacological activity in animal models of anxiety. Despite its widespread use and availability, there has been only one clinical trial of chamomile safety and efficacy in GAD. The current application seeks to build upon the results of that prior chamomile study. In that 8-week, double-blind, placebo- controlled trial, we found a significant superiority of chamomile (vs. placebo) in reducing GAD symptoms. We also found chamomile to be exceedingly well tolerated (vs. placebo). The current application seeks to extend these promising preliminary results by conducting a randomized, double-blind, parallel group, placebo- substitution, long-term safety and efficacy study of chamomile in preventing GAD relapse. For specific aim #1 we will ask: "Does long-term chamomile therapy (vs. placebo) prolong the time to relapse of anxiety symptoms following recovery from GAD?" To answer this question, 180 patients with moderate to severe GAD will receive open-label chamomile extract 500-1,500 mg daily for 8 weeks. Responders to chamomile, who remain well for 4 additional weeks of consolidation therapy, will be randomized to double-blind continuation therapy with chamomile 500-1,500 mg daily or placebo for an additional 26 weeks. We hypothesize that continuation chamomile therapy will result in a prolonged time to relapse (vs. placebo). For specific aim #2 we will ask: "What is the relative safety and tolerability of long-term chamomile therapy (vs. placebo) in patients who have recovered from GAD?" To answer this question, we will examine the following outcome measures: (i) the proportion of patients in each treatment condition who relapse; (ii) the frequency, severity, and duration of treatment-emergent adverse events; (iii) the frequency of discontinuation symptoms during initial double-blind therapy; and, (iv) the frequency of early study discontinuation. We hypothesize that chamomile therapy will result in a lower proportion of anxiety relapses and a lower study discontinuation rate (vs. placebo). We further hypothesize that chamomile therapy will result in a similar frequency of discontinuation symptoms and treatment-emergent adverse events (vs. placebo). PUBLIC HEALTH RELEVANCE: This application, entitled "Long-Term Chamomile Therapy of Generalized Anxiety Disorder," is being submitted to the NIH/NCCAM under PA-07-070. We believe that it comports with the intent of the NCCAM to determine whether available alternative therapies already in use by consumers are safe and effective. The current application builds upon preliminary findings from a prior grant (R21 AT001916) entitled "Chamomile Therapy for Generalized Anxiety Disorder" in which short-term chamomile therapy was found to be superior to placebo in reducing anxiety symptoms. It also found chamomile to be well tolerated. The present application will extend these promising results by studying the long-term benefit of chamomile in preventing relapse of anxiety.