Psychic euosmia among obsessive-compulsive personality disorder patients: A case control study

Psychic euosmia (PE) has been described as a supposed psychological predisposition for which pleasant smells elicit an immediate sense of pleasure, order and calmness in obsessive-compulsive personality disorder (OCPD). In this study we tried to verify the interpretation that PE is the counterpart of disgust that has been associated to contamination and moral purity. Disgust and morality are significantly associated in people with obsessive-compulsive personality traits. We expected that OCPD patients would experience higher levels of PE.

To investigate the PE frequency in OCPD patients and healthy controls (HC) and to evaluate the relationship between PE and disgust.

A single-center, case-control study was conducted in an outpatient service for obsessive-compulsive and related disorders. The sample consisted of 129 subjects: 45 OCPD patients and 84 HC. In both groups we submitted the Disgust Scale Revised (DS-R) and the self-report Structured Clinical Interview for DSM-5 Screening Personality Questionnaire to which we added an additional yes or no question to investigate the presence of PE. In order to verify differences between groups, t-test was employed for continuous variables and ² test for categorical variable; odds ratio was employed to analyze group differences in the PE survey. Correlation was explored with Pearson r correlations.

No differences were observed between groups in gender composition or education. A slight significant difference was found in mean age (t = 1.988; P = 0.049). The present study revealed significantly higher proportions of PE among OCPD patients when compared to HC (OR: 5.3, 2.28-12.46). Patients with OCPD were more likely to report PE (n = 36; 80%) whereas a much lower proportion endorsed PE in the HC group (n = 36; 42.9%). Interestingly, no differences were observed between groups in mean score for the Disgust Scale. There was also no difference between the two groups in any of the Disgust Scale Revised subscales. Moreover, no significant correlations were observed in the OCPD group between PE and Disgust Scale Revised subscales.

Results suggested that PE might be part of the clinical spectrum of OCPD, and it does not reflect the counterpart of disgust. This could also indicate that this phenomenon is a manifestation of orderliness or incompleteness. Further studies will need to be undertaken to better understand PE and its significance in OCPD.