The purpose of this study was to investigate the clinical features of prolonged-type depression. The clinical features chosen as variables were sex, age, family history indicating hereditary predisposition, type of treatment (inpatient or outpatient), age at first onset, number of occurrences of depressive phases, length of the period from the first onset, complications, causes, present state and personality traits.
This time, fifty-two patients with major depression were subjected to this study. They were classified into two groups according to the length of their present illness ; a prolonged group (a period of six months or more) and a control group (a period of under six months). The two groups were examined for the prevalence of clinical features. It was found that, there were statistically significant relations between the two groups with regard to the number of occurrences of depressive phases, the length of period from the first onset, the present state, and personality traits.
Therefore, it was shown that these four variables appear to be clinical features related to prolonged depression.