Distinguishing delusional beliefs from overvalued ideas in Anorexia Nervosa: An exploratory pilot study

Characterised by the belief that more weight needs to be lost-despite emaciation, failing organs, medical instability and prospect of death-Anorexia Nervosa (AN) is a condition in which irrational, and highly-skewed, beliefs can be of delusional intensity. However, the nexus between delusion and rational awareness and how this is related to body image acceptance and perception has yet to be examined in AN. The current study aims to investigate the relationship between body dissatisfaction and beliefs of delusional intensity in an adult AN inpatient sample.

Twenty-one adults (n_(women) = 20; n_(men) = 1), with a mean age of 27 years old (SD = 10), presenting for inpatient treatment for AN (ranging in severity from mild to severe; M_{(Body Mass Index)} = 17 kg/m²; M_{(Length of Stay)} = 22 days) participated in the study. Participants' dominant beliefs (related to AN) and level of insight (delusional; overvalued idea; or fair insight) were measured using either the Brown Assessment of Beliefs Scale (BABS) or the Nepean Beliefs Scale (NBS). The degree of body dissatisfaction was determined by examining the discrepancy between "perceived" and "ideal" body perception. To determine subjective and objective beliefs both the Contour Drawing Rating Scale (subjective) and computerised Body Image Assessment Software (objective) were used.

Almost one quarter (23.7%; n = 5) of participants appeared to have beliefs of delusional intensity related to their body shape (M = 27.4; SD = 23.03). Although a positive linear trend was indicated, there were no significant differences in body dissatisfaction scores between level-of-insight. Individuals whose belief was categorised as delusional were more likely to hold a negative affective body image state based on their ratings on the body image state survey when compared to the group who had good/fair insight (95% CI [0.53, 18.19]; p = 0.03).

The current exploratory pilot study concurs with others in the published literature that demonstrate that approximately 25 percent of participants with AN may have delusional ideas. The implications for treatment in similar samples warrant attention. Future research should also seek to understand the clinical significance of this delusional categorisation, the benefits of its utility in this population, and its relation to the severity of AN or stage of illness.