OBJECTIVES: Real-world treatment patterns and health care resource utilisation for patients with GAD in the United States are not fully defined.  METHODS: Data from the 2003-2007 Thomson Reuters MarketScan® Commercial Claims and Encounters and Medicare Supplemental and Coordination of Benefits databases were utilised for analysis. For the current analysis, participants with a diagnosis of GAD (ICD-9 CM 300.02) between January 1, 2004 and December 31, 2006 were included. The sample was divided into the following five subgroups: patients receiving non-pharmacological treatment, first-line therapy only, first-line+augmentation within 90 days of index prescription, first-line+switch within 90 days of index prescription and second-line therapy only. Additionally, GAD patients were compared with healthy controls without GAD or other mental health conditions. RESULTS: In total, 23,553 GAD patients (mean age range: 41.6-48.1 years; 56.1-68.6% female across the five groups) were included (non-pharmacological, n=7055; first-line only, n=6538; first-line+augmentation, n=903; first-line+switch, n=1953; second-line only, n=7104). Paroxetine was the most commonly used first-line treatment at index (first-line cohorts: 48%, 42%, 41%, respectively). In the second-line only cohort, a benzodiazepine (37%) or second-line SSRI/SNRI (27%) were the most commonly used agents at index. Benzodiazepines were the most commonly prescribed agents for augmentation of, or switching from, first-line treatments (augmentation 52%, switch 44%). Overall, GAD patients had higher health care utilisation and significantly higher total health care costs versus healthy controls (mean per patient: $8058 vs. $2938, p<0.0001). On average, GAD patients incurred an additional $425/month in direct healthcare costs in the 1-year post-index period versus healthy controls. CONCLUSIONS: The real-world management of GAD is both complex and costly. Paroxetine was the most-widely used first-line treatment for GAD. Benzodiazepines were the most widely used agents for augmentation of, or switching from, first-line treatments, and for second-line therapy. Total health care costs were 2.7 times higher for GAD patients compared with healthy controls.