Baseline presentation of atypical anorexia nervosa in Singaporean adolescents: a retrospective cohort study

While atypical anorexia nervosa (AAN) has been found to present with significant physical and psychological complications, the presentation of AAN has not been described in a multi-ethnic Singaporean population. This retrospective cohort analysis aimed to characterize the baseline presentation of adolescents with anorexia nervosa (AN) (N = 317) and AAN (N = 141) in a Singaporean cohort that presented to a specialist paediatric eating disorder program between January 2010 and October 2020 for assessment. In patients with AAN, there were increased proportions of males (16% vs. 7%) and of Malay ethnicity (11% vs. 4%) compared to AN. Compared to adolescents with AN, adolescents with AAN had lower rates of admission (61% vs. 81%), bradycardia (45% vs. 75%), and hypotension (7% vs. 21%) but had a higher rate of syncope (13% vs. 7%). Likewise, adolescents with AAN had higher rates of self-harm and drug overdose (14% vs. 1.5%) requiring admission, more purging (45.1% vs. 14.8%) and more shape concerns. Highlighting the severity of the illness, Singaporean adolescents with AAN presented with physical complications of malnutrition and had more severe eating disorder psychopathology and a higher frequency of other psychological comorbidities than did adolescents with AN.