'Silent stroke' and depression

Summarized by Robert W. Griffith, MD
March 30, 2000 (Reviewed: November 11, 2002)

Introduction

Some elderly people with cerebrovascular disease have symptoms of depression such as apathy, cognitive impairment, and psychomotor retardation. Magnetic resonance imaging (MRI) in these individuals shows areas of hyperintensity in the white and gray matter. The associations suggested by these findings have been explored further in a large population (over 3,500 subjects), as part of the Cardiovascular Health Study being conducted in 4 counties in Pennsylvania, Maryland, California and North Carolina, USA.

Method

In 1989 and 1990 the Cardiovascular Health Study recruited subjects over 65 who were randomly selected from Medicare eligibility lists. Of those asked, 3,660 (58%) were prepared to undergo cranial MRI scans in years 4, 5, and 6 of the study. Depressive symptoms were measured using the short version of the CES-D scale, which contained 5 items on mood, 2 on energy, and 1 each on irritability, concentration, and sleep.¹ Additional tests were done to evaluate activities of daily living (ADL - self-care), instrumental activities of daily living (IADL - use of phone, shopping, etc), and a modified Mini-Mental State Examination (3MS - for cognitive impairment). Blood pressure measurements and cardiovascular history were also assessed.

Trained readers scored white matter MRI lesions in the periventricular and subcortical areas using a 10-point scale. Grey matter lesions were included if they were cortical or in the basal ganglia, and had a vascular pattern - these have been described previously as "infarct-like lesions".

Analyses were done using CES-D quartiles and other non-MRI variables closest in time to the MRI scans. Logistic regression models were applied initially to all 4 CES-D quartiles, and then to the highest and lowest quartiles.

Results

The higher CES-D scores were significantly associated with older age, female sex, nonwhite race, hypertension, coronary heart disease and higher disability scores (ADL and IADL).

The severity of lesions in the white matter was found to be significantly associated with the CES-D score quartiles. However, the numbers of white matter lesions were not related to depression symptom scores. Basal ganglia lesions - both the numbers of small and the numbers of large lesions - were associated with CES-D quartiles.

In the logistic regression analyses, the severity of the white matter lesions and the number of large basal ganglia lesions were no longer significantly associated with CES-D scores. On the other hand, the number of small basal ganglia lesions remained associated. This indicates fairly conclusively that small basal ganglia lesions on MRI are a significant independent predictor of depressive symptomatology.

Comment

A limitation of this study was the use of the short CES-D test; the authors believe that employing quartile scores for analysis overcomes the shortcomings of this modified test. The large size of the study also compensates for possible inter-reader differences in MRI interpretations.

While most psychiatric syndromes have no obvious pathologically recognizable lesions, the astute clinician should always consider possible organ causes. This study examined a large number of older persons, and found that common symptoms of depression are associated with small lesions in the basal ganglia that are diagnostic of damage to long penetrating arteries supplying subcortical areas. The basal ganglia area is involved with the regulation of motor function, and such lesions may be responsible for the reduction of psychomotor activity commonly seen in depression. According to the authors of this study, the occurrence of such lesions may be related to risk factors for small-vessel disease (e.g. hypertension, diabetes).

The results of this study suggest that in some patients, depression may indicate the occurrence of a "silent stroke", which should lead the physician to look for other risk factors for a full-blown stroke or vascular dementia - hypertension, diabetes, hypercholesterolemia, smoking, and physical inactivity.

Source

• Cerebrovascular disease and depression symptoms in the Cardiovascular Health Study. DC. Steffens, MJ. Helms, K. Krishnan, GL. Burke, Stroke, 1999, vol. 30, pp. 2159--2166

Footnotes
1. The CES-D scale: a self-report depression scale for research in the general population. LS. Radloff, Appl Psychol Meas, 1977, vol. 1, pp. 385--401

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