In agreement with prior findings in patients with psychosis (Corcoran et al., 2005; Malaspina & Coleman, 2003), negative, but not positive, symptoms were associated with poorer nasal chemosensory performance, for both odor identification and odor thresholds. Moreover, the present findings show that negative symptoms inversely impacted on odor detection and olfactory ERP measures, with reduced amplitudes of N1 sink and P2 source both linked to more negative symptoms. However, there was no overall difference between CHR patients and healthy controls in the morphology of olfactory ERP/CSD waveforms, N1 and P2 component topographies, and responsivity to changes in odor intensity. The latter finding in particular makes it unlikely that the lack of group differences is merely due to poor data quality, yielding a low signal-to-noise ratio and therefore obscuring true effects – quite the contrary. Given evidence of markedly reduced olfactory ERPs in schizophrenia (Kayser et al., 2010; Turetsky et al., 2003a), the preserved olfactory ERPs in CHR patients may indicate that olfactory ERP abnormalities do not emerge before disease onset, thereby implicating a state rather than a trait measures. However,
