Doctors should consider irritability a possible symptoms of bipolar disorder when they are diagnosing the condition in children, new research suggests. Investigators found that a small percentage of children with bipolar disorder have manic episodes without also having extreme elation, and these episodes often are diagnosed on the basis of irritable mood only. The researchers say that while irritable-only mania is not common, it does exist, particularly in younger children. The scientists add that though this symptom is also a characteristic of other psychiatric disorders such as attention-deficit hyperactivity disorder, irritability should be considered in a bipolar diagnosis as well.