No association between psychometrically-determined schizotypy and olfactory identification ability in first-degree relatives of patients with schizophrenia and non-psychiatric controls

ObjectiveThis study examined potential associations between schizotypy—including positive, negative, and disorganized domains—and olfactory identification ability. Based on a prior report (Park, S., Schoppe, S., 1997. Olfactory identification deficit in relation to schizotypy. Schizophr. Res. 26, 191–197), it was hypothesized that positive and negative schizotypy would be associated with poorer olfactory identification ability, at least among male participants.MethodAs part of a larger study, the Schizotypal Personality Questionnaire (SPQ) and University of Pennsylvania Smell Identification Test (UPSIT) were administered to 98 participants, including 44 healthy first-degree relatives of individuals with schizophrenia and related disorders and 54 non-psychiatric controls. Potential associations between SPQ subscales and UPSIT score were examined while considering the effects of sociodemographic variables on these measures.ResultsSPQ and UPSIT scores were not significantly different in first-degree relatives and controls. There was no evidence of an association between SPQ domains and UPSIT score, even when controlling for possible confounding variables, including age and educational attainment.ConclusionsThe nascent literature on potential associations between schizotypy and olfactory identification ability has yielded mixed findings to date. The current study does not support a correlation between these two markers, and this lack of association—in addition to equal olfactory identification performance in relatives and controls—casts doubt on the utility of the UPSIT as a measure of an endophenotypic trait. Future research would benefit from larger, more diverse samples; the addition of objective, interviewer-based measures of schizotypy; and attention to potentially confounding sociodemographic variables.