Masking is a behaviour or strategy used by many Autistic people to appear non-Autistic and blend in with a neurotypical society. The goal of this observational study is to understand the relationship between masking, anorexia nervosa symptoms and brain structure in Autistic people. The main questions this study aims to answer are: * Do Autistic individuals with anorexia nervosa show differences in structure or function of the brain relation to Autistic individuals without anorexia nervosa? * Do Autistic individuals with anorexia nervosa display higher levels of masking than Autistic individuals without anorexia nervosa? * Are there indeed relationships between levels of masking, anorexia nervosa symptoms and brain structure in Autistic people? Researchers will compare Autistic people without anorexia nervosa to Autistic people with anorexia nervosa to see if there are differences between groups. Participants will: * Complete a series of questionnaires focused on eating disorder symptoms, autistic traits, autistic masking and psychological well-being * Undergo an MRI scan at the Aberdeen Royal Infirmary