An 8 year old child has shown of lack of interest in studies for last 6 months. He has frequent quarrels with his parents and has frequent headaches as anexcuse to avoid school. What would be the most appropriate clinical diagnosis in this patient?

Since the person in the question is showing a hostile behavior which is impairing his academic activities for the last 6 months, the most appropriate next step would be to rule out Oppositional defiant disorder.Oppositional defiant disorder is a recurrent pattern of negativistic, hostile or defiant behavior that lasts longer than 6 months and creates disturbances in at least one of the domains of child functioning including social, academic or occupational impairment. The symptoms of this disorder is usually evident around 6-8 years. Ref: Kaplan and Sadock's Comprehensive Textbook of Psychiatry, 9th Edition, Page 3586, 3580.