Efficacy of open-label venlafaxine in subjects with major depressive disorder: associations with neuroendocrine response to serotonergic and noradrenergic probes.

An open-label pilot study explored the relationship between severity of depressive symptoms and venlafaxine dose required for clinical efficacy in outpatients with major depressive disorder (MDD). The utility of the neuroendocrine response to serotonergic (ipsapirone) and noradrenergic (clonidine) probes as predictors of venlafaxine dosage required for effective treatment was also explored. Nineteen medically healthy medication-free outpatients over 18 years of age who met criteria for MDD were studied.