Background. Panic disorder is a prevalent, often disabling, disorder among primary-care patients, but there are large gaps in quality of treatment in primary care. This study describes the incremental cost-effectiveness of a combined cognitive behavioral therapy (CBT) and pharmacotherapy intervention for patients with panic disorder versus usual primary-care treatment.

Method. This randomized control trial recruited 232 primary-care patients meeting DSM-IV criteria for panic disorder from March 2000 to March 2002 from six primary-care clinics from university-affiliated clinics at the University of Washington (Seattle) and University of California (Los Angeles and San Diego). Patients were randomly assigned to receive either treatment as usual or a combined CBT and pharmacotherapy intervention for panic disorder delivered in primary care by a mental health therapist. Intervention patients had up to six sessions of CBT modified for the primary-care setting in the first 12 weeks, and up to six telephone follow-ups over the next 9 months. The primary outcome variables were total out-patient costs, anxiety-free days (AFDs) and quality adjusted life-years (QALYs).

Results. Relative to usual care, intervention patients experienced 60·4 [95% confidence interval (CI) 42·9–77·9] more AFDs over a 12-month period. Total incremental out-patient costs were $492 higher (95% CI $236–747) in intervention versus usual care patients with a cost per additional AFD of $8.40 (95% CI $2.80–14.0) and a cost per QALY ranging from $14158 (95% CI $6791–21496) to $24776 (95% CI $11885–37618). The cost per QALY estimate is well within the range of other commonly accepted medical interventions such as statin use and treatment of hypertension.

Conclusions. The combined CBT and pharmacotherapy intervention was associated with a robust clinical improvement compared to usual care with a moderate increase in ambulatory costs.