Olfactory Training and Emotional State

During the past three decades, researchers have paid particular attention to the study of olfactory disorders in depression. Recent studies have shown that depression is characterized by a change in olfactory and emotional perception resulting in a decrease of the perception of positive stimuli (odors and facial expressions) and an increase in perception of negative stimuli (odors). Moreover, it has also been shown in healthy subjects that the presence of minor depressive symptoms leads to a decreasing of olfactory sensitivity. However, odor discrimination was not impaired in these subjects. This observation suggest the presence of a change in "targeted" olfactory perception in people with depressive symptoms without reporting major depression. In addition, studies in subjects with olfactory disorders (following respiratory tract infections or following Parkinson's disease) have shown an improvement in olfactory function after daily training with odors during 12 weeks. From all these observations, the hypothesis is that an olfactory training could improve the overall olfactory functioning and the emotional perception of the subjects presenting minor depressive symptoms and of the depressed patients.