Answer:
IED is diagnosed primarily after ruling out more common mental illnesses or abnormal behaviors. This is because many traits of IED can exist without the condition in a person with an aggressive personality. This is also because IED very closely resembles Bipolar manic episodes, and the possibility of the patient having bipolar disorder must be ruled out. The main feature that draws a psychiatrists attention to the possibility of a patient having IED is the nature of the episodes, when acts of aggression are grossly out of proportion to what ever triggered them or completely spontaneous.