The Evaluation of Olfactory Function in Patients With Schizophrenia.

Soleimani Robabeh,Jalali Mir Mohammad,Ahmadi Reza,Badri Mahan

doi:10.5539/gjhs.v7n6p319

Soleimani Robabeh, Jalali Mir Mohammad + Show 2 more

Open Access

https://doi.org/10.5539/gjhs.v7n6p319

Copy DOI

Abstract

The aim of this study was to compare olfactory threshold, smell identification, intensity and pleasantness ratings between patients with schizophrenia and healthy controls, and (2) to evaluate correlations between ratings of olfactory probes and illness characteristics. Thirty one patients with schizophrenia and 31 control subjects were assessed with the olfactory n-butanol threshold test, the Iran smell identification test (Ir-SIT), and the suprathreshold amyl acetate odor intensity and odor pleasantness rating test. All olfactory tasks were performed unirhinally.Patients with schizophrenia showed disrupted olfaction in all four measures. Longer duration of schizophrenia was associated with a larger impairment of olfactory threshold or microsmic range on the Ir-SIT (P = 0.04, P = 0.05, respectively). In patients with schizophrenia, female subjects’ ratings of pleasantness followed the same trend as control subjects, whereas male patients’ ratings showed an opposite trend. Patients exhibiting high positive score on the positive and negative syndrome scale (PANSS) performed better on the olfactory threshold test (r = 0.37, P = 0.04). The higher odor pleasantness ratings of patients were associated with presence of positive symptoms.The results suggest that both male and female patients with schizophrenia had difficulties on the olfactory threshold and smell identification tests, but appraisal of odor pleasantness was more disrupted in male patients.

Highlights

Patients with schizophrenia have selective impairments in the temporolimbic and frontal lobe regions of the brain
The results suggest that both male and female patients with schizophrenia had difficulties on the olfactory threshold and smell identification tests, but appraisal of odor pleasantness was more disrupted in male patients
There were no differences between the patients with schizophrenia and healthy controls in the percentage of male and female participants, mean age, or handedness

Summary

Introduction

Patients with schizophrenia have selective impairments in the temporolimbic and frontal lobe regions of the brain. Olfaction is closely associated with these neuroanatomical regions, and is intimately related to the affective and mnemonic functions that they subserve (Turetsky et al, 1995). Deficits in smell identification, considered to be connected to central olfactory mechanisms, are widely reported in schizophrenia (Atanasova et al, 2008). It was shown this impairment to be correlated with deficits in motivated behavior and emotional expression as well as with impaired verbal and nonverbal memory (Compton et al, 2006; Malaspina et al, 2002; Seckinger et al, 2004). A number of studies have shown that smell identification deficits can exist in people with intact olfactory sensitivity (Kopala, Clark, & Hurwitz, 1989; Kopala, Clark, & Hurwitz, 1993; Striebel, Beyerstein, Remick, Kopala, & Honer, 1999)

Objectives

Results

Discussion

Conclusion