LOW-LEVEL SERUM ANTICHOLINERGICITY AS A SOURCE OF BASE-LINE COGNITIVEHETEROGENEITY IN GERIATRIC DEPRESSED-PATIENTS

Depressed geriatric patients show substantial intersubject variability in cognitive performance, which complicates attempts to evaluate the cognitive effects of depression and of antidepressant therapy. This va riability may reflect the multiple medications older patients take, ma ny of which have anticholinergic effects. This study examined whether serum anticholinergicity (SA) explained some of the variability in dep ressed geriatric patients' memory performance. Before starting antidep ressant treatment, 36 elderly depressed subjects were given a verbal l earning test. At the same time, a blood sample was taken and analyzed by radioreceptor binding assay to determine their SA level. Nineteen o f the subjects had detectable levels (mean = 0.28 pmole atropine equiv alent). Subjects with an SA of zero showed significantly better delaye d recall than did those with a positive SA level. Thus, even very low SA may produce subtle decrements in memory performance, an area of cog nition known to be highly sensitive to anticholinergic effects.