Anorexia Nervosa is a serious mental illness and is frequently seen in young females in childhood and adolescence. The most common ages of onset of anorexia nervosa are the mid teens.

To our knowledge this is singular report of a case of delusional disorder in which Anorexia Nervosa preceded the onset of psychotic symptoms. Age and sex of our case are unusual in Anorexia nervosa.

In this report a rare case of Anorexia nervosa is presented in which the patient is a 32 year old male with poor socioeconomic background from a developing country who subsequently experienced a distinct onset of delusional disorder. After four weeks, delusional disorder and Anorexia Nervosa resolved due to treatment by atypical antipsychotics (Risperidone).

The association between anorexia Nervosa and Delusional Disorder is important. In the case which is reported here delusional thoughts started six month after anorexia nervosa when the patient became extremely thin and cachectic.

In fact the theory of occurrence of psychotic disorder as a result of severe malnutrition is intensified.