UCLA researchers have obtained the first direct evidence that successful behavioral therapy for a relatively common form of mental illness can produce the same type of changes in brain circuitry that are observed with successful drug therapy.
The discovery has two major implications for the future treatment of a variety of mental disorders, including depression, experts said. First, a growing number of studies are showing that each disorder may have a characteristic pattern of brain activity that could allow easier diagnosis of the problem. Perhaps more important, the new study shows that successful treatment causes specific changes in mental activity, providing the opportunity for objective assessment of treatment success.
In the new study, the changes were found in the brains of people with obsessive-compulsive disorder, an incapacitating illness that affects as many as 4 million Americans and is characterized by unwanted thoughts and uncontrollable obsessions, such as the repeated washing of hands. One-third of the sufferers are children and adolescents.
Researchers have previously shown by sophisticated imaging techniques that the disorder is linked to excess activity in the right caudate nucleus, which serves as a thought-regulating center in the brain. Recently, Dr. Lewis Baxter and his colleagues at UCLA have found that this over-activity disappears when the disorder is brought under control with drugs.
Baxter reports today in the Archives of General Psychiatry that identical reductions in excess caudate activity are observed when the patients undergo successful behavioral therapy. This study "is a startling confirmation of what 'ought to be,' " said Dr. Daniel X. Freeman, a UCLA psychiatrist who is editor of the journal.
"Disordered behavior and altered brain function should not be a surprise, nor should shifts with effective treatments be," Freeman said. "But they are actually visible here for the first time."
"This is really terrific," added Dr. Thomas R. Insel, a behavioral neuroscientist at the National Institute of Mental Health. Some researchers had argued that Baxter's earlier findings of decreased activity after pharmacotherapy were either a coincidence or an unanticipated byproduct of the drug's action. "This paper makes it quite clear that that . . . possibility can be ruled out" and that the change is indeed due to therapy itself."
Obsessive-compulsive disorder, usually called OCD, is often compared to a "hiccup of the mind." It is characterized by constant, senseless, intrusive thoughts (obsessions) and rituals (compulsions) acted out to relieve the anxiety produced by the obsessions.
Baxter and his colleagues used a technique called PET scanning, which measures metabolic activity in the brain, to study nine patients who received only drug therapy and nine who received only behavioral therapy.
After 10 weeks, seven of the nine who received drug therapy showed a reduction in excess activity in the caudate, which Baxter says acts as a kind of filter for thoughts originating elsewhere. These patients also displayed a reduction in OCD symptoms, while the two patients who showed no changes in brain activity had no relief in symptoms.
Six of the nine patients receiving behavioral therapy also had reduced symptoms, and they showed an identical reduction in excess activity in the caudate. Patients who did not respond to the therapies showed no changes in their PET scans.
Baxter said he has since studied patients who have received both types of therapy, and they show an even greater reduction in the excess activity, suggesting that behavior therapy should not necessarily be used as a replacement for drugs. Some patients cannot tolerate the drugs and others do not handle behavioral therapy well. But most use both techniques together because that provides the best results.
Victims with obsessions spend hours preoccupied with thoughts or fears about dirt, germs, fire, death, lucky and unlucky numbers or symmetry and exactness. To overcome these thoughts, they act out eccentric rituals--checking lights, doors, windows, locks, appliances and homework, washing hands, showering or bathing, or arranging possessions, such as clothing or silverware or even pencils on a desk.
Taken to the extreme, these behaviors can be physically incapacitating, preventing the person from doing anything else.
Fortunately, over the past few years, scientists have developed pharmacological and behavioral therapies that can ameliorate symptoms in the bulk of patients. Antidepressants such as clomipramine (Anafranil) and fluoxetine (Prozac) can reduce symptoms significantly, although they may take six to eight weeks to begin working and can have significant side effects.
Behavioral therapy also is useful. It is accomplished by placing the patients in a stressful situation and showing them that nothing will result from it.
A patient who fears dirt, for example, might be asked to touch a "dirty" object, like a desk, and, with support from the therapist, refrain from washing. Gradually, they move on to more feared objects.
Eventually, the fears are severely reduced, and in many cases are eliminated.
By using drugs or therapy or a combination of both, about 70% to 80% of patients with the most extreme symptoms can have significant improvement or be cured, according to Dr. Judith L. Rapoport, a psychiatrist at the National Institute of Mental Health.
Today's study follows another, earlier this month, in which researchers at Washington University in St. Louis used PET scanning to identify specific changes in brain activity associated with depression. Eventually, psychiatrists hope to use such information to develop more specific therapies.