Data were drawn from Medstat's 2002 MarketScan Database, a convenience sample of more than 5.5 million privately insured employees and their dependents aged 0 to 64 years from the largest U.S. firms, covering a wide range of health plans and employers. Mental health service use was identified by scanning all 2002 claims and encounters for selected diagnoses, provider types, and procedure codes. Antidepressant use was identified from pharmaceutical claims. Mental health service use was defined as a claim with one of the following: a primary or secondary diagnosis of a mental health or substance use disorder, including tobacco addiction; a service provided by a mental health specialist; or a service coded as individual or group counseling or as mental health or substance abuse treatment.