Double depression, the combination of major depression and dysthymia, is associated with poor health-related quality of life (HRQoL) and increased health service utilization.

To determine the prevalence of double depression, its associated morbidity and use of health services and antidepressants.

A random and representative sample of the South Australian general population was interviewed. The mood module of the Primary Care Evaluation of Mental Disorders (PRIME-MD), the Short-Form Health Status Questionnaire (SF-36) and Assessment of Quality of Life (AQoL) instruments were administered, and data relating to health service utilization, antidepressant use and role functioning were collected.

Double depression was present in 3.3% of the population. The use of health services was significantly higher in this group than those with no depression, or dysthymia or major depression alone. Only 15.2% had attended a community health service, 18.2% had seen a psychiatrist, 10.1% a psychologist, 16.2% a social worker and 9.1% any other counsellor in the last month. While 41.4% were currently taking an antidepressant, the average doses of the two most commonly prescribed antidepressants were below the maximum recommended doses, and the use of antidepressant augmentation strategies was also minimal.

While double depression is associated with increased morbidity and use of health services, the optimum use of both pharmacological and nonpharmacological treatments is clearly lacking in this community sample.