OBJECTIVES: To identify predictors for high treatment costs in individuals diagnosed with Generalized Anxiety Disorder (GAD) with or without pain. METHODS: This analysis was conducted using the PharMetrics Integrated Outcomes Database. Individuals aged 18-64 diagnosed with GAD (ICD9-CM: 30002) between 1/2003 and 6/2004 who had continuous eligibility 6-month prior and 1-year following GAD diagnosis were identified. Annual treatment costs during the year after GAD diagnosis were examined. The highest spenders (top 10%) of patients were compared with the rest on demographics, medication use and costs. Logistic regressions were used to identify predictors for high treatment costs. Patients with pain or without pain were examined separately. RESULTS: A total of 36,435 patients (67% female, mean age 41.5 years) were included in this analysis. The mean treatment costs were $49,248 for the top 10% spenders and $3,836 for the rest. The top10% spenders accounted for 58.8% of the total costs. Patients with pain (N=22,133) were associated with higher costs than those without pain (N=14,302) ($11,445 vs. $3,630, p<0.001). Logistic regressions revealed significant risk factors for high costs including diagnoses of schizophrenia (odds ratio (OR)=2.03, p<0.001), diabetes (OR=1.61, p<0.001), asthma (OR=1.55, p<0.001), neuro-pain (OR=1.48, p<0.001), musculoskeletal pain (OR=1.46, p<0.001), depression (OR=1.31, p<0.001), and alcohol abuse (OR=1.66, p<0.001); prior utilization of narcotics (OR=1.62, p<0.001), emergence services (OR=1.57, p<0.001), hospitalizations (OR=1.60, p<0.001). Similar predictors were obtained for GAD with pain but fewer predictors for GAD without pain. CONCLUSION: This analysis showed that the top 10% spenders of GAD patients consumed nearly 60% of the total costs. GAD patients with pain incurred nearly 3 times as much cost as GAD patients without pain. The presence of prior pain, depression, other comorbidities, and prior resource utilization were significant predictors for high treatment costs. Special attention should be paid to those high costly patients in management of GAD.