Olfaction in child and adolescent anorexia nervosa.

Previous studies indicate disturbed olfactory functions in anorexia nervosa with presumable relationship to the clinical symptom of food aversion and weight loss. However, these studies are in part limited due to inadequately matched control samples, insufficient exclusion criteria, complex interactions of the olfactory and trigeminal system, and the lack of regard to co-morbidity and medication. Thus, we investigated olfactory function in 26 female adolescent patients with anorexia nervosa and 23 healthy controls matched for age, gender, handedness, and intelligence. No significant group differences were identified. Controlling for co-morbid disorders, psychopharmacological treatment, and depressivity revealed superior olfactory identification performance in the "pure" anorexia nervosa group (n = 15) in contrast to the controls. Superior identification may be mediated by increased attentional processes towards food stimuli in patients with anorexia nervosa. Effects of co-morbidity and medication highlight the role of neurobiological factors in the etiology of anorexia nervosa. Furthermore, as other neuropsychiatric disorders such as Parkinson's disease or attention deficit hyperactivity disorder show distinct olfactory function patterns, olfaction may be suitable as phenotypic marker with potential relevance for (differential) diagnosis in neuropsychiatric disorders.