BIOLOGICAL AND CLINICAL VALIDATION OF ATYPICAL DEPRESSION

Depressed patients with (a) mood reactivity alone (MR group), (b) mood reactivity plus one or more associated features (atypical depression, AD group), and (c) patients with neither mood reactivity nor atypical depression (non-MR/AD group) were compared on their cortisol response to 75 mg of desipramine (DMI), a relatively selective norepinephrine reuptake inhibitor. AD patients exhibited a significantly higher corti sol response to DMI compared with MR and non-MR/AD patients, suggestin g that atypical depression may be associated with a less impaired nore pinephrine system. MR and non-MR/AD patients did not differ, suggestin g that mood reactivity alone is not associated with the biological pro file observed in atypical depression. Results indicate that while mood reactivity may be necessary for the diagnosis of atypical depression, the additional presence of at least one associated symptom is require d for a distinct biological profile. Our findings provide further biol ogical validation of the concept of atypical depression.