Differential impact of glucocorticoids: Performance on a neuropsychological battery

Abstract

Extensive evidence from animal and human studies suggests that glucocorticoids have a major impact on cognitive functioning. The hippocampus and dorsolateral prefrontal cortex are two structures which contain high concentrations of neuronal receptor sites sensitive to glucocorticoids, which when occupied, are known to produce both short- and long-term changes in neuronal activity. It is therefore of interest to investigate how early life experiences with glucocorticoids might impact the cognitive abilities, behavior, and, by implication, developing brain structures. Hence, the present study examined relations between chronic administration of glucocorticoid-based corticosteroids and performance on a neuropsychological battery of cognitive and behavioral tasks. The study used samples of children and adult non-asthmatics, asthmatics, and asthmatics receiving prescription corticosteroids. We found that children and adult asthmatics who received prescription corticosteroids exhibited deficits on tests of episodic memory, cognitive mapping, and working memory. In contrast, no differences were present between individuals in the groups on a variety of demographic, and cognitive and behavioral functions not related to hippocampal or dorsolateral prefrontal functioning (e.g., motor skills, language, estimated intelligence). Additionally, asthmatic adults with no history of corticosteroid use show some difficulty on tasks of working memory and cognitive mapping. Their performance is neither as efficient as healthy adults, nor as inefficient as asthmatics receiving prescription corticosteroids. Finally, the data also suggest that the detrimental impact of corticosteroids on functioning of the hippocampal and dorsolateral prefrontal cortex may be rather chronic than acute. Adult asthmatics with a history of corticosteroid prescriptions, but no use in at least the past year, continue to show the same deficits as documented in asthmatic adults with current corticosteroid prescriptions. This observation is in direct contrast to reports of cognitive performance returning to normal as glucocorticoids return to baseline levels. However, it is in accordance with the literature that suggests more permanent damage due to excessive glucocorticoid exposure.