Olfactory reference disorder - empirical insights to a new ICD 11 diagnosis.

Olfactory reference disorder (ORD) is defined as a persistent preoccupation with the belief of emitting an offensive body odour, even though no actual odour is present. The ICD-11 has newly introduced olfactory reference to the catalogue of mental disorders, however, standardized assessment tools allowing further research on this diagnosis are scarce. The objective of this study was to test the ORD screening tool (ORD-ST), a questionnaire we developed based on the ICD-11 criteria. The ORD-ST, as well as questionnaires on mental health and questionnaires and tests on olfaction were completed by a sample of 279 participants. The ORD-ST identified three underlying factors: conviction of possessing a perceivable body odor, checking and modification of body odor, and social impairment, together explaining 38.6 % of the variance. Retest-reliability over the course of one week was high to acceptable for the social impairment and checking subscales, and low for the conviction subscale. ORD symptoms positively related to anxiety, depression, and somatic symptoms, but not to olfactory sensitivity and olfactory attitudes. Based on those findings, we generated the hypothesis for an aetiological model of the olfactory reference disorder, in which the transition from temporary to stable beliefs of emitting a perceivable (and offensive) odor marks the crucial transition.