Authors:
Lin A, Brewer WJ, Yung AR, Nelson B, Pantelis C, Wood SJ.
Authors notes:
Schizophr Res. 2015;161(2-3):156-62.
Keywords:
At-risk, Longitudinal, Olfaction, Olfactory identification, Orbitofrontal cortex, Psychosis, Schizophrenia, Smell, Ultra-high risk
Abstract:
Background: We have previously reported that olfactory identification (OI) deficits are a promising premorbid marker of transition from ultra-high risk (UHR) to schizophrenia, but not to psychotic illness more generally.
Whether this remains the case at longer follow-up, and whether there is decline in OI ability are unclear.
Method: The University of Pennsylvania Smell Identification Test (UPSIT) was administered to 81 participants at baseline (identification of risk for psychosis) and 254 individuals at follow-up.
Forty-nine participants underwent UPSIT assessment at both time points.
UPSIT scores were investigated at an average of 7.08. years after identification of risk in relation to transition to psychosis, a diagnosis of schizophrenia, and psychosocial/functional outcome.
Results: UPSIT scores at baseline and follow-up did not differ between participants who transitioned to psychosis and those who did not.
Similarly, there were no significant differences on UPSIT scores at baseline or follow-up between individuals with a diagnosis of schizophrenia and transitioned individuals without schizophrenia.
Those with a poor functional outcome showed significantly lower baseline UPSIT scores than participants with good outcome.
There was no significant association between functional outcome and follow-up UPSIT scores.
There were no significant changes in UPSIT over time for any group.
Conclusions: These results suggest that impaired OI is not a good marker of the onset of psychosis and schizophrenia, but may differentiate UHR individuals who experience a poor functional outcome, regardless of transition status.