Olfactory reference syndrome: a systematic review of the world literature

The nosological status of olfactory reference syndrome (ORS) is a matter of debate and there is uncertainty as to what treatments are effective.

The world literature was searched for reports of cases of ORS. Clinical, nosological and therapeutic information from cases meeting proposed diagnostic criteria for the disorder was summarized and tabulated.

A total of 84 case reports (52 male/32 female) were found. Age of onset was <20 years in almost 60% of cases. Smell-related precipitating events were recorded in 42%. Most patients could not smell the smell or only did so intermittently. Authors of the reports expressed reservations about the delusional nature of the belief in slightly under half of the cases. Over two-thirds were improved or recovered at follow-up, with the disorder responding to antidepressants and psychotherapy more frequently than to neuroleptics.

ORS is a primary psychiatric syndrome that does not fit well into its current classification as a subtype of delusional disorder, both in terms of its nosology and its response to treatment.