Reduced olfactory sensitivity, discrimination, and identification in patients with alcohol dependence

Background: Various olfactory deficits have been reported in the alcohol-induced amnestic syndrome (Korsakoffs syndrome). Less is known about olfactory functioning in nonamnesic and nondemented alcoholic patients. Methods: Olfactory performance of 30 alcohol-dependent patients was assessed unirhinally using the Sniffin' Sticks (threshold, discrimination, identification, composite TDI score) and compared with that of 30 healthy controls, matched for sex, age, and smoking status. Results: Patients showed significantly reduced olfactory sensitivity (higher threshold), discrimination, and identification compared with controls. No group differences were observed in laterality. Identification and discrimination group differences remained significant, after controlling for differences in sensitivity. Olfactory deficits in patients were present independent of age, gender, and duration of abstinence (<3 months) and were not attributable to smoking or general cognitive abilities. More than half of the patients (56.7%) could be classified as hyposmic. Lower overall olfactory functioning (TDI) was associated with longer duration of a regular alcohol intake and higher values of gamma-glutamyltransferase (GGT). Conclusions: Olfactory dysfunction is common in nonamnesic and nondemented patients with alcohol dependence. Results suggest a detrimental effect of alcohol on central olfactory processing.