| Quality of Life After Stroke: Clinical, functional, psychosocial and cognitive correlates | ||
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In the present study the prevalence of post-stroke depression was high, more than half of the ischemic stroke patients having depression at the 3-month follow-up visit and almost half of them at the 12-month visit. The results also showed that the proportion of patients suffering from major depression increased from 9% to 16% during the follow-up. In other studies using psychiatric examinations in diagnosing depression, the prevalence of PSD has varied from 24% to 41%, major depression occurring in 12-31% of patients and minor depression in 9-29% of patients, depending on the time elapsed after stroke (Åström et al. 1993, Burvill et al. 1996, Pohjasvaara et al. 1998). Robinson et al. (1987) found a stable 14% prevalence of depression up to 2 years in a subsample of their original group. In the study of Åström et al. (1993) the majority of patients with depression experienced remission within the first year, the prevalence of major depression decreasing from 31% at 3 months to 16% at 12 months after the stroke.
The occurrence of depression in the present series was even higher than in most of the previous studies, but the prevalence of major depression was lower (Morris et al. 1992, Åström et al. 1993, Herrmann et al. 1998). The differences in the occurrence of major depression may be due to the selection of the study population. Contrary to those of the previous reports the present patients had experienced only their first-ever stroke and the patients with other central nervous system lesions, as well as with previous psychiatric illnesses were excluded. The increase in the prevalence of major depression during the follow-up may be due to the fact that patients with limited awareness of their deficits avoid depression at the acute stage. Eventually they have to face the demands of everyday life with the loss of cognitive, verbal and functional abilities, and this may contribute to the development of a depressive mood.
A clear-cut association between the categories of depressive illness and the degree of cognitive deficits assessed by a pattern of standardized neuropsychological tests was found at 3 and 12 months post-stroke. Very few previous prospective studies have been carried out using both neuropsychological tests for diagnosing cognitive impairment and psychiatric examinations for diagnosing post-stroke depression. When comparing the simultaneous effect of depression and aphasia on cognitive impairment, depression was an independent correlate at 12 months, of the tests reflecting non-verbal problem solving, memory, and attention and psychomotor speed, but aphasia was associated with all the tests.
Stroke often causes cognitive impairment, the domains most frequently affected being memory, orientation, language and attention, and constructional and visuospatial functions (Tatemichi et al. 1994, Pohjasvaara et al. 1997, Hochstenbach et al. 1998). It is also known that depressive patients without brain damage perform poorly on cognitive tasks, especially those involving memory and concentration (Austin et al. 1992, Veiel 1997). In the study of Austin et al. (1992) the most vulnerable functions in major depression were memory and psychomotor speed. The present findings suggest that the depressive stroke patients also performed poorly in the tests of non-verbal problem solving, which has not been found in the depressive patients without brain damage (Austin et al. 1992).
The presence of PSD was associated with old age in the present study. Previously depression has been found to be frequent in young patients (Neau et al. 1998), while in some studies (Sharpe et al. 1994, Kotila et al. 1998) it has been related to old age. The lack of social support and both functional and cognitive impairment may increase the risk of depressive disorders in the elderly (Sharpe et al. 1994). As has been shown in the previous studies (Sinyor et al. 1986, Parikh et al. 1987, Åström et al. 1993, Sharpe et al. 1994, Herrmann et al. 1998, Kotila et al. 1998, Neau et al. 1998). the depressive patients of the present study were more dependent in the ADL and had more severe impairment and handicap than those without depression both at 3 and 12 months post-stroke.