Early and late onset depression in old age: different aetiologies, same phenomenology

Abstract

Background: Phenomenological differences between older patients with early onset (EO; onset of first major depressive episode before 60 years) and late onset (LO) depression have been inconsistent but, if real, may reflect differences in aetiology. We aimed to compare aetiological factors, phenomenology and cognitive function in older patients with depression by age of onset. Methods: Subjects were all patients ≥60 years old ( n=73) from 407 consecutive attenders to a Mood Disorders Unit, diagnosed with DSM-III-R Major Depressive Episode, at or close to the nadir of their episode. Putative risk factors were assessed by structured interview. Psychological morbidity and depressive symptoms were assessed by the 21-item Hamilton Rating Scale for Depression, CORE rating of psychomotor disturbance, Newcastle Endogeneity Scale, Zung Depression Scale and General Health Questionnaire. Cognition was assessed by tests of memory, attention, executive function and motor speed. Results: Personality abnormalities, a family history of psychiatric illness and dysfunctional past maternal relationships were significantly more common in EO depression. The two age of onset groups were essentially similar in terms of depressive sub-type and severity, phenomenology, history of previous episode, and in neuropsychological performance. Limitations: Use of self-report data, moderate sample size, sample not age-matched, tertiary referral patients. Conclusions: EO and LO depression are similar phenotypically, but differ aetiologically. The pursuit of mechanisms which predispose depressive episodes may be heuristically more valuable than further investigation of individual depressive features in distinguishing early from late onset depression.