Is chronic primary major depression a distinct depression subtype?

Eighteen chronic primary major depressives differed little from 106 nonchronic primary major depressives when compared on multiple clinical variables, including symptoms, longitudinal course, and family history. Chronic depressives had an earlier age of illness onset, more depressive episodes and were more likely to have attempted suicide at some time in their life. It is our interpretation that this data leaves open the issue of whether chronic depression is a distinct depressive subtype.