How many different symptom combinations fulfil the diagnostic criteria for major depressive disorder? Results from the CRESCEND study.

BACKGROUND: The polythetic nature of major depressive disorder (MDD) in DSM- IV and DSM-5 inevitably leads to diagnostic heterogeneity. AIMS: This study aimed to identify the number of depressive symptom combinations actually fulfilling the DSM-IV diagnostic criteria that can be found in Korean MDD patients and the relative frequencies of each combination. METHODS: Using the data from the Clinical Research Center for Depression (CRESCEND) study in South Korea, we enrolled 853 MDD patients diagnosed using DSM-IV and scored as 8 or more on the Hamilton Depression Rating Scale (HAMD). Descriptive statistical analyses were performed to reveal the degree of diagnostic heterogeneity of the MDD. RESULTS: This study identified 119 different depressive symptom combinations. The most common combination consisted of all nine depressive symptom profiles, and nine different combinations were each present in more than 3% of the patients. CONCLUSION: The findings support the criticism that the diagnosis of MDD is not based on a single mental process, but on a set of 'family resemblances'.