The validity of diagnosis of melancholic depression according to different diagnostic systems.

Background: Melancholic versus nonmelancholic depression dichotomy is perhaps the most widely accepted distinction in categorization of depression. This research aims to compare RDC, DSM-III, DSM-III-R, DSM-IV and ICD-10 melancholic/endogenous/somatic and nomelancholic/nonendogenous/nonsomatic depressive patients with regards to biological variables thyroid stimulating hormone (TSH), basal and post dexamethasone cortisol levels, age, age of onset of depression, psychosocial stressors, and severity of depression.

Methods: Sixty-five patients who had been diagnosed as having major depression according to DSM III-R, using SCID were included in this study. Patients were divided into melancholic and nonmelancholic subtypes using RDC, DSM-III, DSM III-R, DSM-IV and ICD-10 criteria and groups were compared on the basis of biological variables, as well as age, psychosocial stressors and the severity of depression.

Results: RDC endogenous depressives were older, more severely depressed and had higher cortisol levels then RDC nonendogenous depressives. DSM III-R melancholics were older, more severely depressed, reported fewer numbers of psychosocial stressors and had lower levels of TSH than nonmelancholics. DSM-IV melancholics were more severely depressed, had higher basal and post dexamethasone cortisol levels and lower TSH levels. The ICD 10 somatic depression group contained more severe, older depressives with lower TSH levels.

Conclusion: The results of this research show that different criteria may identify different groups of patients as having melancholic depression. They also partly support the hypothesis that endogenous or melancholic depression have a biological basis. LIMITATIONS OF STUDY: The study involved a relatively small sample size from a single centre and the results are based on this relatively small sample.