Chronically elevated levels of cortisol have been associated with
changes in cognitive functioning and brain morphology. Using
Cushing's disease as a model to assess the effects of high levels of
cortisol on cognitive functioning, 27 patients with Cushing's disease
were examined at baseline and three successive follow-up periods up to 18
months after successful surgical treatment. At all follow-up periods,
patients were administered cognitive tests as well as measures of plasma
and urinary free cortisol. Structural MRIs and a depression measure were
taken at baseline and one-year follow-up. Results showed that there is a
specific pattern of significant cognitive and morphological improvement
following successful treatment. Verbal fluency and recall showed recovery,
although brief attention did not. Age of participants was a significant
factor as to when recovery of function occurred; younger patients regained
and sustained their improvement in cognitive functioning more quickly than
older participants. Improvement in verbal recall also was associated with
a decrease in cortisol levels as well as an increase in hippocampal
formation volume one year after treatment. Overall, these findings suggest
that at least some of the deleterious effects of prolonged
hypercortisolemia on cognitive functioning are potentially reversible, up
to at least 18 months post treatment. (JINS, 2007, 13,
21–29.)