Impairment of odor hedonics in men with schizophrenia

Olfactory deficits in patients with schizophrenia, including those of odor identification, detection threshold sensitivity, discrimination, and memory, have been well described. Deficits in emotional perception, processing, and experience have also been reported, with anhedonia being one of the core features. While anatomical connections testify to the relationship between olfaction and emotion, there has been little investigation of the hedonic properties of odors in schizophrenia. This study examined intensity and hedonic judgments in patients with schizophrenia to determine whether these functions were differentially impaired.

Suprathreshold scaling of odor intensity and pleasantness was acquired by using the Suprathreshold Amyl Acetate Odor Intensity and Odor Pleasantness Rating Test given to 30 patients (15 men and 15 women) with a DSM-IV diagnosis of schizophrenia and 30 age- and sex-matched healthy comparison subjects.

Despite virtually identical ratings of odor intensity, male patients were impaired in the assignment of odor pleasantness to amyl acetate. This gender-specific diagnostic group difference was not explained by variability in symptom severity or negative/positive symptoms. The impact of smoking status and general cognitive impairment on this deficit was also insignificant.

Findings reveal a gender-specific disruption in the ability to attribute appropriate hedonic valence to odors in male patients with schizophrenia. This difficulty in identifying the hedonic valence of odors, despite intact intensity ratings, is consistent with clinical observations of anhedonia and points to a neural substrate that might contribute to the emotional disturbances seen in patients with schizophrenia.