Joiner, his PhD students, and other collaborators have taken the data from their research and formed a theory about why people commit suicide…

Thomas Joiner

Bright-Burton Professor of Psychology

Why do people commit suicide? Lots of people are depressed and hopeless, many severely. Why do some choose to end their lives and others do not? Thomas Joiner, Bright-Burton Professor of Psychology, has spent much of his career trying to find out.

One gene has shed some light. Joiner’s current research into the serotonin transporter gene indicates that it “seems to render a person vulnerable to future suicidal behavior.” From the moment of conception “this gene predisposes people to impulsivity (acting recklessly and out of control) and a proclivity to negative emotions (depression, anxiety).”

Joiner, his PhD students, and other collaborators have taken the data from their research and formed a theory about why people commit suicide—“they are experiencing the emotional pain of depression or anxiety and also have lost the fear and pain of self-injury.”

The desire for death, according to Joiner, is comprised of two psychological states. One is a perception of being a burden to others, having let everyone down, and the other is a feeling of not belonging, not feeling connected to a family or a relationship. Alone, neither of these states is enough to instill the desire for death, but together they produce a desire that can be deadly when combined with the ability to enact self-injury.

In his new book, "Why People Die By Suicide,” Joiner says that those who kill themselves not only want to die, they have learned to overcome the instinct for self-preservation through practice. Suicide victims get used to danger, fear and pain. They may do this in a variety of ways over their lifetime. For some this practice is deliberate. They engage in reckless behavior, cut or otherwise hurt themselves, or have repeated suicide attempts. Others may have a history of accidents or medical procedures, while still others become inured vicariously, that is, they are exposed on a daily basis through their work to pain and suffering. Eventually, self-injury and dangerous situations become unthreatening and mundane, according to Joiner, making suicide easier to carry out.

"Some people think that those who commit suicide are weak," he said. "It's actually about fearlessness. You cannot do it unless you are fearless, and this is behavior that is learned."

Knowing the risk factors makes prevention possible, Joiner said, noting that maintaining good interpersonal relationships is essential. "If you think you belong or that you are contributing, you are going to be protected from suicide no matter what else is going on. Part of the tragedy of suicide is that, unlike other conditions, it’s often just a perception, one that is correctible through the right kinds of treatment.”