Background. Research shows mixed results regarding executive functioning (EF) deficiencies in adolescent Anorexia Nervosa (AN), contrasting with established EF impairments in adult AN patients....Show moreBackground. Research shows mixed results regarding executive functioning (EF) deficiencies in adolescent Anorexia Nervosa (AN), contrasting with established EF impairments in adult AN patients. This study aimed to assess EF and its association with Body Mass Index (BMI) in adolescent girls with first-onset AN. Method. 79 AN patients were compared to 75 matched healthy controls (HC), all females aged 12-22. EF was assessed using the Central Coherence Index (CCI) of the Rey Complex Figure Test (RCFT) and the Behavior Rating Inventory of Executive Functioning (BRIEF). Standardized BMI scores (BMI-SDS) were used to determine the influence of BMI on EF. Measurements were taken at baseline (T1) and one-year follow-up (T2). Results. Total EF scores showed no differences between AN and HC at baseline or follow-up. Compared to HC, AN patients had significantly worse scores on the BRIEF subscales Flexibility (p < .001; p < .001), Emotion Regulation (p < .001; p = .006), and Initiative (p < .001; p = .006), and significantly better scores on Orderliness and Neatness (p = .002; p < .001). P-values represent T1 and T2 respectively. At baseline, AN patients scored significantly higher on the RCFT CCI (p = .009). There was no significant relation between BMI-SDS and EF. Conclusions. Compared to HC, AN patients had normal EF scores with mild weaknesses in set- shifting, emotion regulation, and initiating skills, and strengths in orderliness and neatness. Changes in EF were unaffected by BMI-SDS. This study enhances understanding of EF in adolescent AN patients, which can aid the development of treatment programs.Show less