Correlation of depressive symptoms and olfactory dysfunction in patients on hemodialysis

A possible link between depression and olfactory dysfunction has been suggested in the literature, in research projects using the olfactory bulbectomy model. In human studies using a syndrome-oriented approach, such an association has not been reported consistently. The aim of the study was to test the association of olfactory dysfunction with depression using a symptom-oriented approach.Paients and methods: Twenty eight end-stage renal failure patients took part in this project. The patients olfactory identification ability was tested with the University of Pennsylvania Smell Identification Test (UPSIT). Immediately before olfactory testing, the subjects completed the Zung self-rating scale, which provides data on symptoms of depression in this group of patients.

The mean value of the number of mistakes made in the olfactory identification ability (UPSIT test) by the total sample was 14.0±4.5, with a range 6-22. Half of the symptoms seem to bear an influence on the olfactory identification performance. Patients experiencing decreased libido and dissatisfaction exhibited significantly reduced olfactory function, as contrasted to those not experiencing these symptoms. The above results remain practically unaltered even after taking into account such probable confounding factors as age, sex, olfactory detection threshold and duration of illness.

These findings support previous evidence indicating that olfactory dysfunction may be related to specific depressive symptoms in humans. The present findings also suggest that the symptom-oriented approach is an effective research tool for the elucidation of such clinical issues. The need for further research in this field is pointed out.