The effect on memory of chronic prednisone treatment in patients with systemic disease.
There have been no systematic investigations of the effects of glucocorticoid treatment on memory in a clinical population despite experimental and clinical evidence that such treatment could cause memory disturbance. We conducted both cross-sectional and longitudinal studies. In Study 1, we administered tests of both hippocampal-dependent explicit memory and hippocampal-independent implicit memory to twenty-five prednisone-treated patients with systemic disease without CNS involvement and 25 matched clinical controls. All treated patients were taking doses of 5 to 40 mg of prednisone daily for at least 1 year. The glucocorticoid-treated group performed worse than the controls on tests of explicit memory, but the groups did not differ on the implicit memory task. Multiple regression analyses suggested that elderly patients are more susceptible to memory impairment with less protracted treatment. The results of Study 2, a prospective, longitudinal study of the effects of prednisone on memory across 3 months of therapy, suggest that even acute treatment can adversely affect memory. The observed alteration in memory was not secondary to inattention, affective disturbance, generalized global cognitive decline, or severity of disease. Results reported here, combined with previous clinical and experimental reports, indicate that the risk of memory impairment should be carefully considered before initiating treatment with glucocorticoids. Conversely, use of glucocorticoids should be considered in the differential diagnosis of memory loss. Finally, the potential benefit of anti-inflammatory treatment in Alzheimer's disease might be counterbalanced by possible iatrogenic memory impairment, at least when synthetic glucocorticoids are considered.