The April 2010 issue of Scientific American includes an article by Thomas Insel, a psychiatrist and neuroscientist who is the director of the National Institute of Mental Health. In "Faulty Circuits," Insel describes new findings in the neurocircuitry of mood disorders.
Many illnesses previously defined as "mental" (like autism and schizophrenia) are now recognized to have a biological cause, according to Dr. Insel, but because mental disorders were not marked by conspicuous lesions in the brain, our understanding of them has lagged behind other areas like Parkinson's disease and stroke. Neuro-imaging, he writes, has "opened up the black box of the brain" so that mental disorders can be studied in the context of problems in the brain's "electrical circuits." According to Insel:
This new view is already producing seismic shifts in psychiatry, opening avenues to more empirical diagnosis of mental illnesses and providing insights into their underlying causes, which promises more effective forms of treatment.
For example, Insel argues that depression is fundamentally a brain disorder -- with considerable evidence pointing to "area 25" of the brain (located in the brain's prefrontal cortex) as a hub for the circuitry underlying depression. Area 25 (named by the German neurologist Korbinian Brodmann, who assigned numbers to various regions of the cortex) is now "high-interest real estate among clinical neuroscientists." Helen Mayberg and her colleagues at Emory University have shown that the region is "overly active in depression and that symptom improvement after virtually all forms of treatment, from medication to psychotherapy, is accompanied by decreased activity in this same region."
Based on the Emory study and others, neuroscientists now think of depression as a circuitry disorder involving abnormal activity in area 25, one that disrupts its vast connected network. According to Dr. Insel:
If this conception is correct, resetting the firing of area 25 should moderate each of these downstream centers, thereby lessening the symptoms of depression. . . . . If area 25 can cause the brain, like a computer, to get struck in a loop of abnormal activity, then the goal of treatment might be akin to "rebooting" a computer that has become frozen.
Further research is needed to establish precisely which aspects of brain activity underlie various disorders (including obsessive-compulsive disorder and post-traumatic stress disorder); in addition, data about genes that may increase risk for a particular disorder will help us unravel things. Still, in Insel's words:
From the scientific standpoint, it is difficult to find a precedent in medicine for what is beginning to happen in psychiatry. The intellectual basis of this field is shifting from one discipline, based on subjective "mental" phenomena, to another, neuroscience. Indeed, today's developing science-based understanding of mental illness very likely will revolutionize prevention and treatment and bring real and lasting relief to millions of people worldwide.
The implications for this research are enormous. At the most basic level, it will influence how we treat various mental disorders. Right now they are classified by their symptoms. Reclassifying them based on brain function could lead to a system of diagnosis based on biomarkers -- biological signs such as brain activity patterns or chemical or structural changes specific to condition. The Scientific American article points out that just as blood tests for cholesterol are used in medicine, mental disorders could be diagnosed with greater precision and possibility identified earlier by their distinctive biological markers. This would help determine which interventions are best.
These findings will also change public perception, and enlighten public understanding, of these conditions. "In different generations," Insel writes, "people with mental illness have been stigmatized as possessed, dangerous, weak-willed or victimized by bad parents. Science supports none of this."
All of this also raises complicated questions surrounding our understanding of free will, human agency and individual responsibility. "As we understand more about the details of the regulatory systems in the brain and how decisions emerge in neural networks," Patricia Churchland of the University of California, San Diego, has said, "it is increasingly evident that moral standards, practices, and policies reside in our neurobiology."
This calls to mind the description used decades ago by the biologist Edward O. Wilson, who said that every human brain is born not as a tabula rasa shaped by the experiences and teachings of life but as "an exposed negative waiting to be slipped into developer fluid" (this analogy was used before digital cameras). The lightening and quality of the picture may change, but the imprint on the film will not.
In his 1996 essay, "Sorry, but Your Soul Just Died," the great Tom Wolfe, in discussing Edward Wilson's views, wrote that neuroscience was on "the threshold of a unified theory that will have an impact as powerful as that of Darwinism a hundred years ago." Wolfe warned that "the notion of a self -- a self who exercises self-discipline, postpones gratification, curbs the sexual appetite, stops short of aggression and criminal behavior -- a self who can become more intelligent and lift itself to the very peaks of life by its own bootstraps through study, practice, perseverance and refusal to give up in the face of great odds -- this old-fashioned (what's a bootstrap, for God's sake?) of success through enterprise and true grit is already slipping away, slipping away . . . slipping away . . ."
Tom Wolfe's concern, that we find ourselves on a slippery slope in which individual accountability gradually slides out of the picture, is a legitimate one. But of course most of life is lived on a slippery slope. Every good thing, carried to its extreme, can be abused.
Most people don't believe, and I rather doubt will ever come to believe, that human beings are merely robots who, when programmed a certain way, will act in a certain way. There seems to be a complicated push and pull between free will and how we are hard-wired, between nature and nurture, between our moral beliefs and commitments and our impulses and inclinations.
Fatalism and reductionism are unwise. The fact that there is a biological basis for human behavior shouldn't become an excuse for any human behavior. And we should never get to the point where we say, "Area 25 made me do it." On the other hand, if area 25 does play a key role in things like mental disorders, as it certainly appears, only an obscurantist would want to deny that reality. Our aim should be to find out the truth, as best we can, and to build an appropriate moral life around those realities. We cannot deny science for fear of where it may lead. And for those who suffer from mental disorders -- who have been imprisoned in a dark world not of their own making -- the medical advances we are witnessing may one day lead them to broad, sunlit uplands. That is an impressive and heartening human achievement.
I find myself once again in accord with the teachings of Scriptures, which tell us that suffering is a part of life and can even deepen human character, that we are called to run with endurance the race that is set before us, even as we are told that God Himself does not willingly bring affliction or grief to the children of men. "Lord," a centurion said to Jesus, "my servant lies at home paralyzed and in terrible suffering." To which Jesus said, "I will go and heal him." And the servant was healed that very hour. That is the promise of my faith -- and of modern science.
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