Context: Traditional management options for generalized anxiety disorder (GAD) have produced low remission rates. As a result, the medical community has turned to complementary and alternative medicine for adjunctive treatment.

Objective: To investigate the efficacy of adjunctive osteopathic manipulative therapy (OMTh; manipulative care provided by foreign-trained osteopaths) in individuals with GAD.

Methods: This open-label, nonrandomized, black-box study took place at a tertiary care mental health clinic in Toronto, Canada. Adult outpatient participants aged 18 to 65 years with a primary diagnosis of moderate-severe GAD (HAM-A score of ≥20) with or without comorbidities were enrolled in the study between June 2014 and January 2015. Patients who qualified and completed the study received 5 individually tailored OMTh sessions over the course of 8 to 9 weeks. A diagnostic psychiatric assessment (Mini International Neuropsychiatric Interview version 6.0.0) was conducted to confirm diagnoses, along with physician-administered and self-reported measures of anxiety, including the Hamilton Anxiety Scale (HAM-A), the Beck Anxiety Inventory, and the Intolerance for Uncertainty Scale.

Results: Significant reductions in total HAM-A scores after OMTh were observed (P<.0001). Significant reductions in total Intolerance for Uncertainty Scale scores were also observed (P<.0001). Beck Anxiety Inventory scores were not found to change significantly with OMTh. Response (defined as 50% reduction of symptoms) and remission (defined as HAM-A score of ≤7) rates were found to be 62% and 26.9%, respectively.

Conclusion: Osteopathic manipulative therapy may be a valuable adjunct to conventional therapy in patients with GAD, thus warranting further investigation using double-blind procedures.