given that olfactory deficits have been observed across several neuropsychiatric and neurodegenerative disorders, including Parkinson’s and Alzheimer’s disease, it has been proposed that some aspects of impaired odor processing may share a common dopaminergic pathology, which may affect neurotransmission in the olfactory bulbs (Schecklmann et al., 2013). This is of particular interest given the refined dopamine hypothesis of schizophrenia (e.g., Howes & Kapur, 2009) and evidence that dopaminergic abnormalities precede psychosis onset (Egerton et al., 2013; Howes et al., 2011).
