Studies examining G×E interactions in the prediction of depression have been notably more consistent than studies examining G×E interactions in the prediction of aggression and related phenotypes. Although the diagnosis of depression is frequently comorbid with a range of diagnoses, the symptom of depression is not included in the diagnostic criteria for any other psychiatric disorder. This is in sharp contrast to the symptoms of aggression and inattention, which are included in the diagnostic criteria for multiple behavioral, mood, and anxiety disorders. Integrating dimensional and categorical diagnostic approaches may lead to more refined phenotypes for investigation in future studies.
