May 21, 2015 | Louise Gagnon
Previous research linked elevated levels of cortisol, also referred to as the stress hormone, to resistance to antidepressant treatment, explained Raul Ventura-Junca, MD, PhD, Universidad de Chile, Santiago, Chile, on May 17.
Researchers enrolled 208 patients, 187 with normal thyroid function and 21 noneuthyroid. The diagnosis of depression and the severity of illness were determined by the Mini-International Neuropsychiatric Interview and the Hamilton depression scale (HAM-D17).
The patients with normal thyroid function were treated with fluoxetine (20 mg). Of the 166 patients who started treatment with fluoxetine, 145 continued to 3 weeks of treatment, and 122 continued to the end of 8 weeks of drug therapy.
Of the 122 patients, the 67 who responded to treatment and 48 who remitted all had significantly lower circadian basal salivary cortisol levels than nonresponders (P = .008 and .021, respectively).
“We can conclude that higher cortisol levels are a predictor of resistance to fluoxetine treatment,” said Dr. Ventura-Junca. “If you measure circadian cortisol levels, and patients have elevated cortisol, you should not begin to treat them with either 20 or 40 mg of fluoxetine treatment. You should consider an alternative.”
Salivary cortisol levels remained stable with fluoxetine treatment.
Patients who chose to discontinue treatment before the third week of the study showed reduced levels of salivary cortisol (P = .057), said Dr. Ventura-Junca, speculating that the patients were very good responders to the SSRI.
“We think that these people did not abandon treatment early because of side effects of treatment but because they were already feeling better,” concluded Dr. Ventura-Junca, adding that other factors are likely involved in response to fluoxetine.
[Presentation Title: Cortisol Levels Before and After Antidepressant Fluoxetine Treatment in Chilean Patients With Major Depressive Disorder. Abstract P3-052]