Cortisol response to dextroamphetamine stimulation in depressed outpatients

Area of Science:

• Neuroendocrinology
• Psychiatry

Background:

• Intravenous (i.v.) amphetamine challenge can reveal cortisol release abnormalities in depressed patients.
• Previous studies suggest a blunted cortisol response in endogenously depressed inpatients.

Purpose of the Study:

• To investigate dextroamphetamine-induced cortisol release in 64 depressed outpatients.
• To determine if cortisol response correlates with major depression or endogenous subtype diagnoses.

Main Methods:

• Administered i.v. dextroamphetamine (0.15 mg/kg) to depressed outpatients.
• Assessed cortisol release following drug administration.
• Utilized regression analysis controlling for baseline cortisol, sex, and weight loss.

Main Results:

• 30% of major depressive outpatients showed a blunted cortisol response, compared to 5% of non-depressed individuals.
• While endogenous depressives had a higher rate of blunted response (38%) than non-endogenous (23%), the difference was not statistically significant.
• Regression analysis indicated that depression subtype did not significantly predict cortisol release after controlling for covariates.

Conclusions:

• Abnormal cortisol response to amphetamine in depressed outpatients is not solely explained by major depression or endogenous subtype.
• Baseline cortisol levels, sex, and history of weight loss appear to be more significant factors influencing this neuroendocrine response.