title: Cognitive flexibility and Agouti-related protein in adolescent patients with anorexia nervosa.
abstract: BACKGROUND
  Cognitive flexibility and the flexible learning and relearning of stimulus-reward-associations are important for decision-making and goal-directed behavior. Studies on patients with anorexia nervosa (AN) have shown difficulties in cognitive functions associated with malnutrition and extreme underweight. However, to date we find a lack of neuropsychological studies on cognitive flexibility among adolescent patients with AN. Furthermore, the underlying biological mechanisms remain unclear. Therefore, we aim to examine cognitive functions, especially reward association learning, as a measure of cognitive flexibility in adolescent patients with AN and investigate the relationship between Agouti-related protein (AGRP) and cognitive functions.
  
  
  METHODS
  The study population consists of 30 patients with AN (M(age)=16.2 ± 1.2) and a healthy control group (CG) of 28 female adolescents (M(age)=16.3 ± 1.3). All subjects completed a neuropsychological test battery including the probabilistic Object Reversal Task, the Digit Symbol Test and the Trail Making Test. Patients with AN were explored before and after weight gain, the CG initially and after 3 months.
  
  
  RESULTS
  Subtle deficits in cognitive flexibility were found in patients with AN compared to the CG. After weight gain, the AN group improved relative to their baseline values in most of the variables but did not reach CG values. They still showed slight impairments. Moreover the study revealed a clear association between AGRP levels and cognitive flexibility.
  
  
  CONCLUSIONS
  Cognitive flexibility plays an important role in AN and may be modulated by abnormal levels of the appetite-regulating peptide AGRP. Even subtle impairments in cognitive flexibility can be relevant for the ability to fully engage in therapy and therefore may hinder a prosperous treatment.
authors.affiliation: Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Charité-Universitätsmedizin Berlin, Campus Virchow Klinikum, Berlin, Germany. lea.sarrar@charite.de
authors.forename: Lea
authors.initials: L
authors.lastname: Sarrar
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehrlich
authors.forename: Julia Valeska
authors.initials: JV
authors.lastname: Merle
authors.forename: Ernst
authors.initials: E
authors.lastname: Pfeiffer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Lehmkuhl
authors.forename: Nora
authors.initials: N
authors.lastname: Schneider
mesh_terms: D000293:Adolescent; D054369:Agouti-Related Protein / Q000032:analysis / Q000097:blood* / Q000502:physiology; D000856:Anorexia Nervosa / Q000097:blood* / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology*; D015992:Body Mass Index; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000453:epidemiology; D003863:Depression / Q000097:blood / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009473:Neuronal Plasticity / Q000502:physiology; D009483:Neuropsychological Tests; D012649:Self Concept; D011795:Surveys and Questionnaires
chemical_list: D054369:Agouti-Related Protein