Since the February 2004 FDA advisory's warning of activation syndrome involving antidepressants, growing concerns have emerged over aggression and violence reported in subjects prescribed these drugs. However, activation syndrome remains poorly defined, and controversy regarding the nature of this syndrome continues in the field of psychiatry. Here, we present four medico-legal cases involving activation syndrome, in which one of us served as an expert witness. Analysis of the court's decisions indicated that the court appeared to focus on whether the acts were associated with the subjects' personality or not, leaving the controversy over activation syndrome as an open question. These cases highlighted the need for joint examination by jurists and psychiatrists, since society is likely to continue to be faced with cases of behavioral problems associated with the use of antidepressants.