Psychopathology of mass murderers

Every day, mass murder cases occur in the US, according to the media, although most of them were not reported. From the sense of ordinary people, such criminals look insane. In reality, however, only one-fourth of mass murderers are diagnosed as psychotic or other severe mental disorders.

Independent: Are mass murderers always insane? Researchers don't think so

The prevalence rate of schizophrenia, a representative psychotic disorder, is approximately one percent. Statistics about mood disorders is under broad discussion. Some researchers claim soft bipolar spectrum is seen in one person in every ten. Nonetheless, the vast majority of citizens have no particular mental disorders.

Dr. Michael Stone, a forensic psychiatrist at Columbia University, showed the data of 350 mass murderers. Among them, two-thirds of subjects had no severe mental disorders, while 22 percent had psychoses. Others are categorized to mood disorders or other psychiatric dysfunction.

This proportion seems reliable for my knowledge and experience. The majority of mass murderers are not psychotic. In contrast, patients with serious psychotic symptoms are often difficult to conduct deadly crimes.

On the other hand, many mass murderers have biased thought, distorted cognition, or difficulty of regulating their emotion. Such phenomena can be called as psychiatric symptoms. But, it is another issue whether they should be treated as mentally disordered. Anders Behring Breivik who committed a mass shooting in Norway was suspected of delusional disorder for his extreme ideology. But this possibility was denied by psychiatric examination. And Breivik himself did not want to be treated like a delusional disorder.

The broad definition of mental disorder makes this issue complicated. DSM-5, the newest diagnostic manual includes antisocial personality disorder, conduct disorder, and kleptomania. Many psychiatrists are doubtful for these disorders to be treated as a psychiatric disease. Indeed, the majority of all criminals matches the criteria for antisocial personality disorder, since they have broken the law.

In my sense, it is good that only severe mental disorders are discussed in this context. Different from personality trait, they are well known among psychiatrists as mental disorders which are treatable. We should be deliberate to discuss other diagnoses than them in the context of the cause of the crime and criminal responsibility of the suspect.