Neurobiological views shed light on depression. Parts of the brain that connect to the body's stress system show that depression is physiological as well as emotional.
By
Hara Estroff Marano, published on March 01, 1999 - last reviewed on June 30, 2006
The view of depression emerging from neurobiology labs is radically different from the conventional wisdom on several counts.
First, it overturns the widespread belief that depression is "just" a chemical imbalance. Yes, neurotransmitters like serotonin function abnormally in depression—but so do lots of other things. Second, it challenges the view that this is a disorder "merely" from the neck up. Depression affects the heart and the bones, too. And the body's stress system.
Third, it presents a picture of the brain that is startling even to those whose job is to track its operations (scrap the idea of a little computer with fixed circuitry toiling away inside your head; your brain is reconfiguring itself this very instant). The evidence that the adult brain is much more plastic than anyone recognized, that experience and environment change the brain circuitry underlying emotion, is still, as Rockefeller University neurobiologist Bruce McEwen says, taking scientists by surprise. The surprise is not just kicking off a revolution in our understanding of depression. It will force a revised view of all of human behavior and the capacity for change.
This emerging revolution in understanding depression comes courtesy of refinements in brain imaging techniques—higher resolution in PET scans and magnetic resonance images. "The idea that there is a global derangement of the serotonin or norepinephrine system is not sustainable in light of the recent brain imaging data," the University of Wisconsin's imager-in-chief Richard Davidson reports. "What distinguishes depressed from nondepressed individuals are patterns of regional brain function, differences in specific circuits."
The psychological operations we've always thought of as mental are now traceable biologically to circuits—the brain's wiring and firing patterns—and to molecular mechanics inside brain cells. It's fairly obvious that this knowledge should lead to whole platoons of antidepressant drugs that take new and improved biological tacks to the disorder.
Less obvious may be that the new biology of depression also makes a strong case for non-drug therapies. "Nonpharmacological treatments may exert quite specific biological effects in being able to affect certain select brain regions," Davidson points out. "The deficit in activation of the prefrontal cortex that we and others have identified in depression may be something that can be changed with cognitive therapy." Or a stripped-down and tightly focused component of cognitive therapy called behavioral activation, pioneered by psychologist Neil Jacobson at the University of Washington.
It may also be changed with meditation.
Davidson was encouraged enough to begin his own study of meditation. He is specifically testing how it affects patterns of activation of the prefrontal cortex, whether it activates the left side and stimulates positive emotions, or deactivates the right side, decreasing the volume of negative messages so that they don't disrupt everything else.
The answers are yet to come.
Tags:
adult brain,
antidepressant drugs,
brain,
brain circuitry,
brain imaging,
bruce mcewen,
chief richard,
cognitive therapy,
conventional wisdom,
depression,
heart and the bones,
little computer,
magnetic resonance images,
meditation,
molecular mechanics,
neurobiologist,
neuroscience,
pet scans,
picture of the brain,
psychological operations,
regional brain function,
rockefeller university,
stress system,
understanding depression
