Selective serotonin reuptake inhibitors (SSRIs) became the first line therapy for anxiety and depressive disorders and for many other clinical diagnoses. One of the most disturbing side effects that is observed is a tendency towards aggressiveness among patients receiving medications from this group, mainly during the first (one month) period of therapy. Aggressive behavior tends to occur in some individuals but not in others. Until now most of the cases and reports in the literature demonstrate the extreme events of aggressive behavior. These personality or any other character traits that are more prone to develop aggressiveness have not been studied and it is not clear if this side effect manifests itself just in the extreme rare cases or if it is a more common phenomenon that occurs in a wider group of people.