Olfactory sulcus morphology in patients with current and past major depression

Olfactory deficits have been reported in major depressive disorder (MDD). However, it remains largely unknown whether MDD is associated with abnormalities in olfactory sulcus morphology, a potential marker of olfactory system development. This magnetic resonance imaging study investigated the length and depth of the olfactory sulcus in 29 currently depressed patients, 27 remitted depressed patients, and 33 age- and gender-matched healthy control subjects. Both current and remitted MDD patients had significantly shallower olfactory sulci bilaterally as compared with controls. Only for male subjects, the right olfactory sulcus was significantly shorter in remitted MDD patients than in controls. The right sulcus depth was negatively correlated with number of depressive episodes in the entire MDD group and with residual depressive symptoms in the remitted MDD group. Medication status, presence of melancholia, and comorbidity with anxiety disorders did not affect the sulcus morphology. These findings suggest that abnormality of the olfactory sulcus morphology, especially its depth, may be a trait-related marker of vulnerability to major depression.