Examining age effects on prototypic melancholic symptoms as a strategy for refining definition of melancholia.

ABSTRACT

BACKGROUND: Melancholic depression appears to have a later age of onset than the non-melancholic disorders, and its phenotypic picture also appears to change with age. The latter phenomenon allows clarification of key symptoms of melancholia by examining for age effects on putative melancholic symptoms, thus enabling identification and refinement of the melancholic sub-type. METHODS: We studied 158 patients receiving a diagnosis of unipolar depression (65 melancholic 93 non-melancholic), dichotomised by age and with a higher representation of those with melancholia in the older age band. The severity of individual DSM-IV-TR melancholic candidate symptom constructs were quantified across age groups and diagnostic sub-type. RESULTS: Symptom constructs identified as most clearly associated with age effects in those with melancholia were anhedonia, non-reactivity, diurnal mood variation and, to a lesser degree, psychomotor slowing. When melancholic and non-melancholic patients were compared, non-reactivity, psychomotor slowing and diurnal mood variation were the most differentiating in the older age group. CONCLUSIONS: The capacity of certain symptoms to mark the changing phenotypic expression of melancholia with age may not only assist refined definition of melancholia but inform about underlying causes and, of key importance, explain the suggested differential impact of narrow-action and broad-action antidepressant on those with melancholia across differing age groups.