Mohammed T. Abou-Saleh

AETIOLOGY OF LATE-LIFE DEPRESSION 387Disruption of adrenergic and serotonergic pathways by the lesion,giving depletion of biogenic amines, has been postulated.Robinson and Starkstein 2 considered the location of the lesionin the brain as the single most important aetiological factor inPSD, with the highest frequency of PSD associated with anteriorlesions in the left hemisphere. Their method of neuroradiologicallesion location has been criticized 3 . Lesions of the globus pallidus,putamen and caudate nucleus in association with PSD have beendescribed.A recent literature review by Singh et al. 4 concluded that anydefinitive statements about stroke lesion location and risk ofdepression have not yet been substantiated. Anatomical correlatesof PSD change over time and may explain interstudy differences inthe association of lesion location with PSD 5 . Furthermore, moodchanges may be mediated through the distant effects of lesions, asshown by PET studies, or the lesions may play a facilitatory rolefor another primary mechanism leading to depression. Many ofthese risk factors may be interrelated, e.g. size of lesions,disability, impaired cognition and living in a nursing home.REFERENCES1. Rao R. Cerebrovascular disease and late life depression: an age-oldassociation revisited. Int J Geriat Psychiat 2000; 15: 419–33.2. Robinson RG, Starkstein SE. Current research in affective disordersfollowing stroke. J Neuropsychiat Clin Neurosci 1990; 2: 1–14.3. Burvill PW, Johnson GA, Chakera TMH et al. The place of site oflesion in the aetiology of post-stroke depression. Cerebrovasc Dis 1996;6: 208–15.4. Singh A, Herrmann N, Black SE. The importance of lesion location inpoststroke depression: a critical review. Can J Psychiat 1998; 43: 921–7.5. Shimoda K, Robinson RG. The relationship between poststrokedepression and lesion location in long-term follow-up. Biol Psychiat1999; 45: 187–92.