Olfactory functioning

What is olfactory functioning? 

The olfactory system is the sensory system used to interpret and perceive smell, which may be dysfunctional in people with schizophrenia. Olfactory functioning is hierarchical and involves lower-order processing (detection of the stimulus) and higher-order processing (discrimination and identification of the stimulus). Odour detection occurs at the lowest chemical concentration needed to register an odourant. Odour discrimination involves comparing the differences between multiple stimuli, judging odours as pleasant or unpleasant, or comparing the relative concentration of odours. Odour identification draws on a person’s knowledge and memory to correctly label the smell.

What is the evidence for altered olfactory functioning in people with schizophrenia?

Moderate to high quality evidence suggests a medium to large effect of impaired odour detection, identification, and discrimination in people with schizophrenia compared to people without schizophrenia. A longer duration of illness, taking first generation rather than second generation antipsychotics, and older age were all associated with more impairment in patients. Males and greater smoking rates found less impairment n patients. Moderate to high quality evidence suggests there is impaired olfactory identification, but not acuity, in people at high clinical or high familial risk of schizophrenia.

September 2020

Image: ©s.matheson – neura.edu.au

Last updated at: 5:27 am, 27th August 2021
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