Double depression in an Australian population.

<bold>Background: </bold>Double depression, or dysthymia with superimposed major depression, is a major public health issue that imposes considerable burden on the community. Double depression and its associated morbidity have not previously been delineated in an Australian population.<bold>Methods: </bold>A random and representative sample of the South Australian population was assessed by trained interviewers. 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 related to treatment use and role functioning were collated.<bold>Results: </bold>Double depression was present in 2.2% of the population. This group reported high levels of treatment-seeking behaviour with 90% seeking treatment in the last month and 42.4 % taking antidepressants. They also had a highly significantly poorer quality of life than did others in the community.<bold>Conclusions: </bold>The 2.2% of the population with double depression reported high use of services with poor functioning and health-related quality of life. More effective intervention strategies are required. [ABSTRACT FROM AUTHOR]