Background: Although evidence suggests that there are neurobiological differences between unipolar depression in younger versus older adults, conflicting evidence exists about whether these manifest as clinically identifiable differences.
Method: We conducted a systematic review of aetiological, phenomenological and outcome studies to examine the evidence for a distinction between early onset (EOD) and late onset (LOD) depression. A literature search was completed using the computer databases MEDLINE, EMBASE, PSYCHINFO and PUBMED for papers published between January 1982 and December 2012 which compared groups with EOD and LOD. Studies were included if they were of older people and compared symptoms, aetiological factors or outcomes. We conducted a quality assessment of included articles.
Results: We identified 23 articles which met entry criteria. The only clinical feature which was different between the groups was a higher frequency of a family history of mood disorders in EOD.
Limitations: The number of studies identified was low and their quality was generally poor.
Conclusions: Although neurobiological studies have reported differences between EOD and LOD, generally these do not appear to translate into identifiable distinguishing clinical features.
Keywords: Aetiological factors; Age at onset; Depression; Phenomenology; Treatment.
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