Why Psychotherapy Works: Its Effect on Brain Biology
By Brendan McLean, NAMI Communications Coordinator
The effects of psychotherapy are usually measured on a psychological scale, by looking at symptoms, social functioning, behaviors and emotions. But in the past 20 years, studies have begun to show that psychotherapy also changes the brain’s structure. Any change in psychological functioning is ultimately the product of a change in the physiological structure of the brain.
Until the recent introduction of neuroimaging technologies such as photon emission CT (SPECT), positron emission tomography (PET) and functional MRI, looking at changes in the brain had been difficult to study. These new tools have made it possible to study changes in the brain such as brain activity or blood flow more comprehensively.
The majority of studies published in the past two decades on these technologies have revealed similar brain changes after individuals received either psychotherapy or medication. In 1992, the first study of its kind showed that PET scans of individuals with OCD before and after they received two months of behavioral therapy showed similar results in decreasing glucose metabolic activity in the orbitofrontal cortex and right caudate as the group who received medication as treatment. This study opened the way for an inquest into the relationship between therapy and the emerging field of neuroimaging.
“Psychotherapy has an effect on a person's experience of thinking and feeling so it is intuitive that it has an impact on the brain,” said NAMI Medical Director Dr. Ken Duckworth. “This research may even help make more sense of the longstanding philosophical dilemma of what constitutes the mind and what is the brain.”
More recent studies have begun to clarify how psychotherapy changes the brain and how there are some differences in the changes exhibited in the brain between the two methods of treatment.
Psychopharmacology aims to directly impact the structure and biology of the brain to improve psychosocial functioning, a bottom-up approach. For example, antidepressant use operates more directly on the amygdala, which is directly related to the generation of negative emotion and fear. In contrast, cognitive therapy enacts a change in the amount of activity in the prefrontal cortex, the area of the brain involved in executive functioning and decision-making.
The results of these studies and others show that psychotherapies truly enact their top-down approach, that is, they change the areas of the brain involved in higher-order processing and thinking as opposed to addressing the symptomology of the illness directly.
Forms of psychotherapy such as cognitive behavioral therapy (CBT), interpersonal therapy (IPT) and dialectical behavior therapy (DBT) tend to focus on immediate concerns, problem solving and are goal-oriented. These forms of therapy help the person change the way he or she thinks about and processes events they encounter in their day-to-day life.
Commonly referred to as “talk therapy,” psychotherapy has been found effective for a variety of mental illness including depression, anxiety disorders such as posttraumatic stress disorder (PTSD) and obsessive-compulsive disorder (OCD), bipolar disorder, eating disorders and schizophrenia.
“Making sure you have the right type and match of psychotherapy remains a key challenge,” said Dr. Duckworth. “Being an educated customer about what kind of therapy you are selecting will likely improve your experience and your condition.
At the neurological level, there may simply be more than one way to activate therapeutic pathways in the brain. This is not to say one method is necessarily more effective than the other, as there are likely at least two routes to the get to the same result. One form of treatment may be more effective for one individual than the other. Most of the time, a combination of the two is often most beneficial.
“The science of understanding psychotherapy and the brain is still in its infancy,” said Duckworth. “But the future is bright as more is understood about the brain and neuroimaging techniques.”