Keywords: AN; Anorexia nervosa; 5-HIAA; 5-hydroxyindole acetic acid; 5-HT; 5-hydroxytryptamine; 5-HTP; 5-hydroxytryptophan; LNAAs; Large neutral amino acids; LAADC; L-Aromatic amino acid decarboxylase; MAO; Monoamine oxidase; SSRIs; Selective serotonin reuptake inh