Belief beyond sensation: olfactory reference disorder following post-COVID anosmia

Background

Olfactory Reference Disorder (ORD) is characterized by a persistent belief of emitting a foul or offensive body odour that is not perceived by others, typically accompanied by referential thinking, repetitive behaviours, and social avoidance. In ICD-11, ORD is classified among Obsessive–Compulsive and Related Disorders, while DSM-5 conceptualizes it under Other Specified Obsessive–Compulsive and Related Disorders. Clinically, it includes obsessive, somatic, and delusional features, and patients often present to multiple medical specialties before psychiatric referral. Empirical data suggest that ORD symptoms are more closely related to affective distress than to objective olfactory function [1,2].

Case Presentation

A 35-year-old single male was referred for psychiatric evaluation due to a four-year history of believing that he emitted a disturbing body odour. The symptoms began after COVID-19 infection in 2020, followed by prolonged anosmia lasting approximately two years. Importantly, he reported that he smelled unpleasant even during the period in which he was unable to perceive any odours.

After partial recovery of olfactory function, the belief persisted and intensified. He described odours from breath and sweat, particularly in crowded settings and shortly after leaving home. He reported that the perceived odour increased within minutes of entering public environments. He interpreted neutral behaviours of others—such as opening windows or turning away—as evidence that people were reacting to his odour, although no one had explicitly confirmed this.

No objective malodour was detected during clinical assessment. The patient denied other sensory hallucinations. Affect was mildly anxious, cognition was intact, and insight was markedly limited, with the belief reaching delusional intensity. The condition led to significant functional impairment, including social withdrawal, repetitive bathing, avoidance of public transportation, and job loss. He reported bathing at least twice daily and avoiding close interpersonal contact due to fear of disturbing others. Extensive multidisciplinary evaluations revealed no explanatory pathology. Pharmacological treatment and psychoeducation were offered, but the patient declined psychiatric intervention.

Discussion

In this patient, symptom onset followed prolonged post-viral anosmia. The persistence of odour related conviction in the absence of any sensory input represents a paradoxical dissociation between perception and belief.

Empirical findings show that ORD symptoms are not directly related to objective olfactory sensitivity, supporting the role of higher order cognitive processes. One possible explanation is that prolonged sensory deprivation led to increased reliance on internally generated expectations which persisted after sensory recovery.

ORD is clinically heterogeneous, including obsessive concerns, referential ideas, and, in some cases, delusional conviction . This may explain why restoration of peripheral sensory input does not necessarily resolve symptoms [1,2].

Conclusions

This case suggests that restoration of peripheral sensory function may be insufficient to modify established maladaptive belief systems. In patients with persistent odour complaints and repeated negative medical evaluations, particularly following COVID-19, ORD should be considered. Early psychiatric recognition is important for reducing functional impairment.

References

1. American Psychiatric Association. (2022). In Diagnostic and statistical manual of mental disorders (5th ed., text rev.).
2. Croy, I., Überschär, J., & Bierling, A. L. (2025). Olfactory reference disorder: Empirical insights to a new ICD-11 diagnosis. Psychiatry Research, 351, 116615.