Eligible for inclusion in the review were double-blind placebo-controlled phase II, III or IV randomised controlled trials (RCTs) of any duration, of any active drug treatment for generalised anxiety disorder in adults (aged 18 years or over).
Outcomes of interest were response, remission and tolerability of drug treatments. Response was defined as the proportion of patients who experienced a reduction of at least 50% from their baseline HAM-A score. Remission was defined as the proportion of patients with a final Hamilton Anxiety scale (HAM-A) score of 7 or more. Tolerability was defined as the percentage of patients withdrawing from the trial due to adverse events.
In included trials, duration of treatment ranged from four to 24 weeks. Active treatments included duloxetine, escitalopram, fluoxetine, lorazepam, paroxetine, pregabalin, sertraline, tiagabine and venlafaxine. Although the authors stated that only placebo controlled trials were eligible for inclusion in the review, two trials did not have a placebo arm. There was limited data on patient characteristics. Included trials had inclusion criteria of HAM-A scale scores of ≥18 or ≥20. Most included trials were conducted in the USA or Europe.
The authors initially stated that three people were involved in the process of study selection and an independent reviewer checked a random selection of 10% of selected articles. The authors later stated that a single reviewer assessed publications for data selection.