Reduced olfactory performance in patients with major depression

The aim of the present study is to investigate olfactory sensitivity and od or evaluations in a homogenous sample of unipolar depressive patients using pure olfactory odors. Twenty-four in-patients with major depressive disord er (MDD) were investigated during their acute depressive phase. Eighteen of them participated a second time after Successful treatment. A group of hea lthy subjects, matched by age. sex, and smoking behavior. served as a contr ol. Olfactory sensitivity, as measured by threshold tests, was strongly red uced in patients with severe depression. Additional correlative analyses re vealed that the lowered sensitivity could partly be predicted by high depre ssion scores. After successful medical treatment. these sensitivity differe nces were reduced and did not reach the significance level. The subjective odor evaluations (valence and intensity ratings) were not markedly changed in general. The results reveal that olfactory performance in MDD patients i s reduced at an early perceptional level of stimulus processing. It is disc ussed whether this effect can be attributed to the close functional connect ion between the main olfactory bulb and the amygdala. (C) 2001 Elsevier Sci ence Ltd. All rights reserved.