Early brain changes associated with psychotherapy in major depressive disorder revealed by resting-state fMRI: evidence for the top-down regulation theory

Background Major depressive disorder (MDD) is associated with dysfunction of the emotional circuitry in the brain. Psychotherapy and antidepressant treatment both aid in modulating this dysfunction, albeit probably through different mechanisms. A plausible “top-down” emotional regulation mechanism for psychotherapy has been described in previous studies, but the underlying findings are still contradictory. Methods A total of 23 MDD patients and 20 healthy controls were enrolled. The early neural effects within 5 weeks of guided imagery—a psychotherapeutic method for treating depression—were assessed through resting-state functional magnetic resonance imaging using the regional homogeneity analytical method. Results At baseline, regional homogeneity was reduced in cortical regions and increased in limbic areas in the pre-treatment scans of MDD patients as compared to controls. After 5 weeks of guided imagery therapy, regional homogeneity in the ventromedial prefrontal cortex and the anterior cingulate gyrus both increased. Higher pre-treatment regional homogeneity in the dorsal anterior cingulate gyrus was positively correlated with an improved response to guided imagery therapy. Conclusion The changes in regional homogeneity induced by guided imagery therapy demonstrate that this method of psychotherapy takes effect through a “top-down” mechanism. Future studies comparing various psychotherapeutic methodologies across multiple time points in the treatment course should yield more valuable insights on this topic.