The man who turned himself in to police and was arrested for allegedly killing 19 people at a residential facility for intellectual disabled people in the Kanagawa Prefecture city of Sagamihara turned out to be a 26-year-old former staff member at the institution.
In February, the man had visited the official residence of the speaker of the House of Representatives, passing on a letter that signaled his intent to kill residents of the facility. Shortly afterward, the man resigned from his job. Because he hinted that he was going to carry out the murders, saying such things as, "It's better that people with disabilities don't exist," the Sagamihara Municipal Government committed the man for psychiatric care based on the Act on Mental Health and Welfare for the Mentally Disabled. The man is said to have tested positive for marijuana at the hospital.
Multiple media outlets approached me for my take on the case as a psychiatrist. Most of the questions I was asked focused on whether the attacks could have been due to the suspect's psychiatric state being thrown off as a result of chronic marijuana use, or whether he had a mental illness that made him delusional. At this point, I think neither was the case.
As for marijuana use, any delusions it may cause do not last for long. Marijuana can cause excitement or delusions temporarily, but it is generally accepted that marijuana users return to "normal" when the drug wears off. We know that the suspect spent a long time making meticulous plans for his alleged crimes, which makes it hard to argue that he acted out of marijuana-induced excitement.
Then what about the possibility that the suspect is mentally ill, and was overcome by delusional thoughts? It's impossible to say anything definitive at this point, but based on the letter he wrote to the speaker of the lower house and other information, his arguments are preposterous but his writing does not show signs of unraveling, i.e. delusions. If someone like him were to be brought to my consultation room, I would tell him, not as a psychiatrist but as a human being: "You are wrong." But I would find it difficult to diagnose him with an illness.
Is the type of thinking characterized by the suspect that uncommon, however? In recent years, lack of funding for social security has been raised over and over as a society-wide problem. Social welfare services have diminished and there had been a growing trend toward encouraging those in trouble to work things out themselves. I have patients who come in and tell me that their applications for disability pensions have been denied, saying with downcast eyes, "People like me are nothing but a heavy burden on society." Those who are on welfare because they are ill and cannot work are made to feel inferior. Just take a quick glance at the internet, and it's filled with voices discriminating against and disparaging such people.
Let's ask ourselves this: did the massacre take place against a backdrop of the gradually spreading notion that people who aren't "useful" have no right to live? Society depends on human beings mutually supporting and helping each other. That's something we must reaffirm. (By Rika Kayama, psychiatrist)