Relationship between mental impairment and HPA axis activity in dementia disorders

In 40 patients with Alzheimer's disease (AD, < 65 years), 56 patients with senile dementia of the Alzheimer type (SDAT, > or = 65 years) and 45 patients with vascular dementia (VAD), basal cortisol levels were estimated and the dexamethasone test (DST) was performed. The degree of dementia was assessed according to DSM-III-R and the GBS scale was used for quantitative measures of functional impairment. There were no significant differences in basal cortisol levels. Especially in the VAD group, scores on functional impairment correlated significantly with post-DST cortisol levels. The results indicate hypothalamic overactivity in demented patients which can be correlated to the degree of dementia. In VAD, and to a certain extent also in SDAT, there appears to be a disconnection between cortical areas, including the hippocampus and the hypothalamus.