Background. Few data are available with which to evaluate the association between depressed subgroups, type of treatment and patient retention during episodes of major depression.

Method. This observational study followed 1117 depressed patients over a 12-month period in the primary care setting of six different international sites. The patients were divided into three severity-linked subgroups: moderate to severe depression; moderate depression co-morbid with serious medical conditions; and mild depression.

Results. In general, a low dropout rate was found, with significant differences in the rates across the six sites. However, while there was no statistical significance in the association between the three subgroups of depression and overall dropout rates, we did find that older patients were less likely to drop out, more depressed patients were more likely to drop out, and if patients were on antidepressants they were less likely to drop out. Among the three subgroups of depression, patients with moderate depression co-morbid with serious medical conditions received the lowest amount of antidepressants and had the lowest quality of life.

Conclusion. Although the overall dropout rate in this study was found very low and did differ between the six sites, an association between the use of antidepressants and patient retention was seen. The group of patients with serious co-morbid medical conditions received fewer antidepressants even when the level of their depressive states was taken into consideration. This group was the least satisfied with treatment and had the lowest self-reported quality of life.