Odor identification difficulties may exist in mood disorders, especially when psychotic features are present, according to a recent study. In contrast, the global olfactory dysfunction observed in schizophrenia may not be a feature of other neuropsychiatric conditions. Researchers examined odor identification, odor discrimination, detection threshold, and odor hedonic processing performance in individuals with bipolar I disorder (n=43; n=13 with psychotic features), bipolar II disorder (n=48), major depressive disorder (MDD) (n=134), anxiety (n=48), and no mental disorder (n=72) who participated in a community-based family study. They found:
- Compared to controls, odor identification performance was lower among individuals with MDD and bipolar I disorder.
- Among the latter group, performance was only reduced among those with psychotic features, particularly for pleasant odors.
- Those with MDD showed lower identification accuracy for neutral odors.
- Performances on measures of odor discrimination and detection threshold did not differ by diagnostic group.
Kamath V, Paksarian D, Cui L, Moberg PJ, Turetsky BI, Merikangas KR. Olfactory processing in bipolar disorder, major depression, and anxiety. [Published online ahead of print February 13, 2018]. Bipolar Disord. doi:10.1111/bdi.12625.