Perfectionism in anorexia nervosa: novel performance based evidence.

Existing research into perfectionism in Anorexia Nervosa (AN) is limited by a reliance upon self-report measures. This study used novel performance based measures to investigate whether there is behavioural evidence for elevated perfectionism in AN. 153 participants took part in the study--81 with a diagnosis of AN and 72 healthy controls (HCs). Participants completed two performance based tasks assessing perfectionism--a text replication task and a bead sorting task--along with self-report measures of perfectionism. Significant group differences were observed on both tasks. In the text replication task the AN group took significantly longer compared with healthy controls (p = 0.03, d = 0.36) and produced significantly higher quality copies (p = <0.01, d = 0.45). In the bead sorting task, there was a trend towards more participants in the AN group choosing to check their work compared with the HC group (p = 0.07, d = 0.30) and the AN group took significantly longer checking than those in the HC group (p = <0.01, d = 0.45). Only copy quality uniquely predicted scores on self report measures of perfectionism. This study provides empirically tested evidence of elevated performance based perfectionism in AN compared with a healthy control group.