An Evolving View of Depression

In the world of therapy, Dr. Aaron T. Beck is a rock star.

Considered the father of cognitive behavioral therapy, a form of psychological treatment that has swept the country in recent decades, he has been so famous for so long that some are surprised to find out that he is still, at 87, hard at work.

Beck has recently come out with a new, overarching theory of depression, the mood darkness that in any given year afflicts an estimated 5 percent of Americans (and probably a higher percentage this year).

More than a generation ago, Beck helped overturn the classical idea that depression was "anger turned inward," a form of self-punishment.

Instead, back then he put forth a cognitive model of depression - that it is a problem of negative bias and habits of thought. Any failure means "I am a loser." A rejection means "Nobody loves me."

Now, he has updated his cognitive model with the latest advances in brain science and genetics, and published it in the American Journal of Psychiatry. Beck, a professor of psychiatry at the University of Pennsylvania, cautions that much of the research he cites is still preliminary. But he sketches out a coherent overview of converging psychology and biology that goes roughly like this:

Begin with genes. Beck and others used to speculate about a "blue gene." Researchers are now beginning to identify specific genes that could make the brain "hyperreactive to negative experiences," leading to depression, he writes.

For example, a gene that affects the brain chemical serotonin appears to influence how likely it is that a major stressful event will lead to depression. Studies suggest this serotonin gene is also linked to a tendency toward negative thinking.

How could a gene lead to negative thinking? Well, to continue the example, that serotonin gene appears to make the amygdala, an emotional center of the brain, hyperactive.

Studies have found that a hyperactive amygdala is linked to extra sensitivity to negative stimuli, such as unpleasant images or events.

People end up viewing the world negatively - noticing the weeds, not the flowers.

Other studies suggest a biological pathway to depression involving stress hormones that Beck summarizes this way: Stressful events trigger the hypersensitive amygdala to overact, producing a distorted negative reaction, which prompts excessive stress hormones, leading to depression.

There is also a "top-down" piece of the puzzle: brain scans have found that in depressed people, the prefrontal cortex, known as the seat of rational thought, tends to be underactive.

They are not getting the needed reality check that says "Things are not really so bad." That may help explain how therapy that encourages depressed people to "reappraise" things, to challenge their negative responses, can act to lift mood. Cognitive behavioral therapy aims to help patients by focusing on problems in their thinking and teaching them ways to improve it.

There's more. But it seemed the easiest way to sum it up was to ask Beck what he would say these days if a patient asked, "Why am I depressed?"

His answer: "I would say that there is an interplay of genetic, developmental, and stress factors, and the contribution of each of these factors varies from individual to individual. Some individuals, for example, are depressed only if there is overwhelming stress. Others are vulnerable because of their genetic make up and become depressed with minor stressors."

And how does that answer differ from, say, 20 years ago? Back then, he said, he would have emphasized only the psychological factors, and left the genetic and biological factors "up in the air."

He believes, he said, that even a patient who is biologically vulnerable to depression can be helped by effective therapy. For severely depressed patients, he recommends cognitive therapy in conjunction with medication.

Beck's model of depression has evolved admirably, but it does not make the problem of depression simpler, said Philip Levendusky, director of the psychology department at McLean Hospital in Belmont.

The model reflects the fact that depression is complex and has many dimensions, Levendusky said.

Brain science has made amazing advances in recent years, but it is still light years away from understanding mental illness. Beck's theory is a snapshot of the state of the science - it is, Levendusky said, "a quantum jump beyond where we were once upon a time, and probably three quantum jumps from where we'll ultimately be."

Still, Beck ends his August 2008 American Journal of Psychiatry article, which he said brought him a far greater response than anything else he had written, with optimism.

"I have reason to hope that future research will perhaps provide a new paradigm which for the first time can integrate findings from psychological and biological studies to build a new understanding of depression," he wrote.

And in the meanwhile, said Michael W. Otto, director of Boston University's Center for Anxiety and Related Disorders, depression can be treated even without a full understanding of its origins.

However it starts, he said, it has a life of its own. "It's a pattern that needs to be broken," he said, "and the evidence is that it can be broken."

--NYT