Symptoms of Depression Change With Olfactory Functions

Abstract

Olfactory loss is associated with symptoms of depression. The present study, conducted on a large cohort of mostly dysosmic patients, aimed to investigate whether improvement in olfactory performance would correspond with a decrease in depression severity and, if so, to what extent. In 171 participants, we assessed olfactory function and severity of depression before and after an average interval of 11 months, with many patients improving in function. Separate analyses were conducted for a) the whole group of patients and b) the group of dysosmic patients in both classic and Bayesian ways. Student t-test demonstrates that the whole sample improved consistently, especially within the group of dysosmic patients in terms of odor identification, and the dysosmic group also improved in terms of odor threshold and olfactory functions in general. Pearson correlation showed that the increase in olfactory functions corresponded with the decrease in depression severity, particularly in dysosmic patients. To conclude, the present study results indicate that symptoms of depression change with olfactory functions in general and odor identification in particular.