Uncovering the Source of Suicidality with Brain Science

Are Serotonin Levels the Key Factor in Suicidal Depression?

Charles Barber

"My mother died today. Or perhaps it was yesterday," says Victoria Arango. She's a tall, lean, handsome woman, who happens to be one of the world's most productive neuroscientists. She's just quoted the first line of The Stranger by Albert Camus.

I hadn't expected to be talking about Camus on this dreary Monday morning in our present setting---Arango's orderly but welcoming office in the New York State Psychiatric Institute in northern Manhattan. PI, as everyone calls it, is a gleaming monument to science, situated in a curved, $80-million building sheathed with green-turquoise glass that resembles nothing so much as a large ocean liner.

What was a philosophical issue for Camus is a physiological and biochemical one for Arango. For the last two decades, she's been studying the brains of people who committed suicide, and has discovered that the biochemistry of their brains differs significantly from that of people who don't commit suicide.

Arango and her team hope some day to be able to use physiological evidence to detect people who are at risk of suicide, and then get them into better, earlier treatment and supervision. But there are aspects of their work that trouble me. Could our brains be so sick that they'll kill us? How much do our brain chemicals control our lives, and what control is left to us?

A Collection of Brains

As I sit in Arango's office, I know there's a large room down the hall filled with freezers that hold the brains of 261 people who've committed suicide. She and her collaborators have been collecting such brains for decades.

"The findings are reviewed by a team of psychiatrists here and we come up with a provisional psychiatric diagnosis,” says Arango. “For each 'suicide brain,' we must do a matched control---matched by sex, age, postmortem interval, and race---with which to compare it. So if we have a 40-year-old Caucasian man who died, say, by hanging, we need a matching sample of a white male between age 38 and 42 who died in a natural way."

Later I see the details of one such matched pair in a study she gives me:

Suicide brain: 28 year old white female, brain stored for 4547 days, fell from a height, with diagnosis of major depression and eating disorder, post mortem interval 19 hours.

Match control brain: 27 year old white female, brain stored for 4,313 days, died of a motor vehicle accident, no psychiatric diagnosis, post mortem interval 15 hours.

A Look at the Science

Would you like to see the brains?" Arango says.

"Yes," I answer, a little tentatively.

Once securely placed between glass slides, small slices of brain are frozen until the day of an experiment, when they're brought to room temperature and dried under vacuum. Each brain section goes through 20 different treatments---exposure to radioactive chemicals, immersion in liquids---repeatedly. Each step takes from a few minutes to a few hours. At the end, the slides are placed next to X-ray film and exposed in the dark for varying times, depending on the experiment. The presence of radioactivity in the molecules creates images on the film, and the exposed film reveals the different receptors that tell the story of the serotonin, allowing the scientists to measure the amounts present in the brains of those who committed suicide and those who didn't.

For two decades, Arango has been the principal investigators at this center, the only federally funded program to research suicidal behavior across the life cycle. "We've learned from earlier work that alteration in the serotonin system, which is under significant genetic control, may be a predictor for suicidal behavior," says her research partner, John Mann, Chief of Neuroscience at PI and Columbia University. Their inquiries have led them to zero in on the prefrontal cortex, the area of the brain that lies behind the forehead, which is the source of the brain's "executive functions," including controlling impulsivity. This characteristic has long been implicated with suicide.

Uncovering the Underlying Causes of Suicide

In seeking the biological basis for suicidal impulsivity, Mann and Arango's work has increasingly focused on the presence of serotonin, or lack thereof, in certain parts of the brain, particularly the prefrontal cortex. Serotonin seems to exert a calming influence on the mind in ways that aren't completely understood. Thus the presence of serotonin, in the right place and the right time, might make a person more balanced and less impulsive.

Considering the Implications


Arango is working with people who are already dead. What can all this information do for the living?

"Biology, mental illness, life events, personality traits, and genetics---all are involved in suicide. While I think that nobody will kill themselves without biology, it’s just one part of it," she adds. "Environmental factors, or factors that are influenced by the environment---life events, personality traits, psychiatric disorders---are all huge players. And even genetic expression is related to the environment. My work involves the interactions of all these factors. In other words, we’re not biologically predestined."

But the current trends in psychiatry are mostly toward altering the brain's chemistry, rather than working with the mind. I worry that that subtleties of Victoria Arango's message are lost on some practitioners, who don't realize that the mind, personality, free will, and---dare I say---soul all remain central to the question of whether, and how, we live or die.

This blog is excerpted from “Our Serotonin, Our Selves?". Read the full article here. >>

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Topic: Anxiety/Depression

Tags: add | depression | eating disorder | ED | EFT | female brain | major depression | male brain | mental illness | neuroscience | neuroscientist | parts of the brain | psychiatrist | science | serotonin | sex | SPECT | suicidal | suicide | talking | TED | race

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