Generalized anxiety disorder (GAD) is one of the most common anxiety disorders and has a poor prognosis, although it is often thought to be a minor complaint. This disorder has a chronic course of 5-15 years and longer. Long-term treatment with the commonly used benzodiazepines is controversial because of concerns over tolerance and dependence. We performed a thorough search of the literature for clinical trials of a duration of over 2 months conducted in patients with generalized anxiety disorder in order to identify any successful long-term treatment of this disorder. Only eight long-term reports of studies conducted in well-defined homogeneous groups of patients diagnosed with generalized anxiety disorder were found with the methodology of these studies presenting a number of limiting factors. The results are inconclusive and no reference drug could be identified. In addition, an adequate evaluation of the long-term treatment of GAD has not yet been performed.