The Other Side of Normal

How biology is providing the clues to unlock the secrets of normal and abnormal behavior

What's Normal Got to Do With It?

Understanding the "biology of normal" can help demystify mental illness.

Welcome to The Other Side of Normal blog. I’ll be exploring how the mind and the brain work and how that can help us make sense of our everyday behavior and the roots of mental illness.

One of the arguments I make is that we need to base our understanding of mental illness on an understanding of what I call “the biology of normal”—the basic architecture of the mind and brain. Without a map of how the mind and brain function, our definitions of abnormal and normal depend heavily on what behaviors we decide are unusual, bizarre, or problematic. And those decisions can easily be influenced by cultural trends, historical tradition, or the opinions of “authorities.”

The human brain was designed through natural selection to adapt to the challenges our evolutionary ancestors faced—things like avoiding harm, forming attachments, understanding what other people are thinking and feeling, choosing a mate, and so on. Our genomes are a coded record of these adaptations, and we have circuits in the brain dedicated to solving these challenges. But each of us lives out a particular version of this basic outline as a result of the particular genetic variants we carry and the catalogue of experiences we accumulate over a lifetime. The unique trajectories we follow create a broad spectrum of normal: our individual variations on the theme of human nature.

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Sometimes those variations cause us pain and suffering. Take the case of fear and anxiety—emotions that we all experience and that can be life-saving in a dangerous world. We now know a lot about the brain systems dedicated to detecting threat and avoiding harm. We also know that these systems can go awry. For some of us, genetic variants and life experiences create a fear system that is tuned to see threat when its not really there. That’s the basic problem that connects anxiety disorders from phobias to panic disorder and posttraumatic stress disorder. When our harm avoidance systems are on overdrive, the result can be overwhelming and debilitating.

But anxiety disorders are just one example of a broader picture. The more we learn about how the brain works, the more it seems that many psychiatric disorders involve variations of the same brain systems we use to solve the challenges of everyday life. One implication of this is that there are no bright lines between what we call normal and abnormal. And that makes defining the boundaries of psychiatric disorders an ongoing challenge.

Psychiatry is often accused of “pathologizing normal.” Critics argue that the field is guilty of a kind of diagnostic imperialism – an ever-expanding quest to define normal behavior as disease. In recent months, arguments about drawing a line between mental health and mental disorders have spilled over into the popular media with the announcement that the American Psychiatric Association is revising its diagnostic manual—the DSM. In 2013, the fifth edition of the manual (DSM-5) is slated to be released and proposals to add, subtract, and re-organize the categories of psychiatric disorders have already been posted online (dsm5.org). Inevitably, there’s been a storm of controversy about how the lines are being drawn. In some cases--like the proposal to allow a diagnosis of depression within two months of bereavement--the changes have been decried as another example of medicalizing normal behavior (thedailybeast.com). In others--like the proposal to eliminate Asperger syndrome as a diagnosis--the charge is that categories may end up being too restrictive, sparking fears that people in need will be denied essential services (nytimes.com).

The problem is that when the DSM draws a line in the sand, it’s a lot like drawing a line in the sand. We have to acknowledge that at some level, defining psychiatric syndromes based on clusters of symptoms—which is what the DSM does—requires making a judgment. But that doesn’t mean that psychiatric disorders are mythical creations. As a practicing psychiatrist, I’ve seen the torment that people and families suffer when psychosis, mania, depression, and panic overtake the mind. I’ve seen people so overwhelmed that they would rather end their lives than face a future filled with this torment. So there’s an inevitable paradox: psychiatric illness is all too real, but the more precise we try to be in drawing a boundary between normal and abnormal, the more elusive it becomes.

 

As I suggest in my book (of the same title as this blog):

“Normal and abnormal are like night and day. That is, both are meaningful descriptions of two states that we recognize as different. But the line between them is impossible to draw. When exactly does day become night? We might decide to draw the line at sunset—a specific moment in time that we’ve constructed to separate the two. But that’s clearly somewhat arbitrary. Nevertheless, we’d all agree that day and night are meaningfully real. We schedule our lives around them; we make plans based on them. But we rarely worry about the moment that one becomes the other. We’re comfortable with the fuzziness of twilight.”

But we can improve our approach to defining and understanding psychiatric disorders. And that’s where the biology of normal comes in. By starting with an understanding of what the brain and the mind were designed to do and how they function, we can see where the fault lines are likely to arise. If we want to be on solid ground in describing mental dysfunctions, we need to understand what functions are being dys-ed. Fortunately, a convergence of evolutionary biology, psychology, neuroscience, and genetics is beginning to fill in that picture. And that’s the subject of my book and this blog. In coming posts, we’ll explore the latest dispatches from psychiatry, psychology and neuroscience that are providing the clues to how we become who we are. I welcome your comments and look forward to your feedback.

Jordan Smoller is an Associate Professor of Psychiatry at Harvard Medical School as well as the author of The Other Side of Normal.

Jordan Smoller, M.D., is Associate Professor of Psychiatry at Harvard Medical School and Associate Professor in the Department of Epidemiology at the Harvard School of Public Health. more...

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