Two hundred and twenty five cases of depressive illness were collected using rigorous diagnostic criteria. Of these patients, admitted to the hospital over 30 years ago, 213 were followed-up for periods of time varying between one month and 20 years; the material was recorded in the chart. Findings revealed that less than 5 per cent of the patients ever show a mania in the follow-up period. Depressive males are most likely to have subsequent episodes; depressive females are most likely to become chronic. Chronicity is a limited affair which may last up to 10 years but does not continue indefinitely. When early-onset females are compared to late-onset males, the latter have more subsequent episodes and less chronicity. It is possible that both early-onset females and late-onset males have the same illness, and that these differences are simply related to sex and age at index admission. However, these data may also be interpreted as support for the idea that there are two kinds of depressive illnesses. Early-onset females are considered to be the prototype of depression spectrum disease. They have a great deal of familial alcoholism and sociopathy. Late-onset males are the prototype of pure depressive disease. They have little familial sociopathy or alcoholism. The two groups are different in follow-up as regards frequency of subsequent episodes and chronicity.