Adrenocortical function and depressive illness in mentally retarded patients

Area of Science:

• Neuroendocrinology
• Psychiatry
• Developmental Disabilities

Background:

• Intellectual disability is associated with various health conditions.
• Depression is a common comorbidity in individuals with intellectual disability.
• The dexamethasone suppression test (DST) is a biomarker for depression.

Purpose of the Study:

• To evaluate the utility of the dexamethasone suppression test (DST) in institutionalized adults with intellectual disability.
• To determine the prevalence of hypercortisolemia and DST nonsuppression in this population.
• To identify factors associated with DST abnormalities in individuals with intellectual disability.

Main Methods:

• Administered a 1-mg dexamethasone suppression test (DST) to 85 institutionalized adults with mild to profound intellectual disability.
• Screened participants to exclude false-positive nonsuppression.
• Assessed baseline hypercortisolemia and DST nonsuppression.
• Correlated test results with age, sex, level of intellectual disability, and modified DSM-III criteria for major depressive disorder.

Main Results:

• 36% of subjects had baseline hypercortisolemia, correlated with age, symptoms, and major depressive disorder.
• 24% of subjects were DST nonsuppressors, related to age, female sex, intellectual disability severity, symptoms, and major depressive disorder.
• DST nonsuppression showed 41% sensitivity and 81% specificity for major depressive disorder.
• Age and intellectual disability severity remained significant predictors after controlling for other variables.

Conclusions:

• The DST may be a valid tool for assessing depression in adults with intellectual disability.
• Intellectual disability itself does not invalidate the DST.
• Factors such as age, sex, and severity of intellectual disability influence DST results.