The question sounds naive, but it matters: if psychotherapy is conversation and exercises, can it change anything at the level of biology? Or do only medicines produce “real” change?
The answer neuroimaging research gives is fairly definite.
What is measured
The method is simple in principle: a patient undergoes functional neuroimaging before a course of therapy and after it, and the patterns of activity are then compared — with each other and with the readings of people without the disorder.
One review bringing such studies together was published by Brazilian researchers in The Journal of Neuropsychiatry and Clinical Neurosciences and covered studies of CBT in arachnophobia, social phobia, post-traumatic stress disorder and obsessive-compulsive disorder.
What is found before therapy
Patients show stable dysfunctional patterns of activity. The specifics depend on the disorder:
- in specific phobia — characteristic changes of activity in the dorsolateral prefrontal cortex and in areas connected with processing fear;
- in PTSD — reduced activation in the regions responsible for social cognition and emotion regulation;
- in OCD — changes in the circuits linking the cortex, basal ganglia and thalamus.
This is not a “breakage” in the everyday sense but an entrenched way for neural circuits to work.
What happens after a course of CBT
The main finding of the reviews: after therapy the activity normalises — that is, it comes closer to the patterns of people without the disorder. The changes are most marked in the circuits responsible for regulating negative emotions and inhibiting the fear response.
The logic here is clear even without neurobiology. Exposure is essentially learning: the brain repeatedly gets the experience “the situation happened and no catastrophe followed” and relearns. Learning changes neural connections. That this shows up on neuroimaging is expected rather than surprising.
Comparison with medication
A separate line of research compared the changes after psychotherapy with those after pharmacotherapy. In social phobia and OCD no statistically significant differences were found in the character of the normalisation of activity: two different interventions lead to comparable changes.
This is an important result, and it is easy to misread, so let us be precise: it does not mean that medicines are unnecessary. It means that psychotherapy is not “conversation instead of treatment” but a full intervention with biological consequences. In moderate and severe conditions the combination of psychotherapy and medication is often more effective than either method alone. The decision about medication is the doctor’s.
The practical conclusion
When someone says “talking will not help me, mine is at the level of biology”, they are drawing a conclusion the data does not support. Work with thoughts and behaviour is also an effect on biology, just through a different entrance.
We write about how work in the CBT approach is structured on the method page; about the practical side, in how therapy works.