In a recent study published in the American Journal of Psychiatry online, researchers found an association between brain activation and response to cognitive-behavioral therapy (CBT) in adolescents with obsessive compulsive disorder (OCD). The findings may help clinicians personalize OCD treatment.
Psychological treatment for OCD typically includes CBT. However, about 30 to 50% of patients do not respond to treatment. To help find out why, study authors wanted to explore the neural mechanisms behind OCD and what happens in the brain during CBT as compared to a control therapy (stress management).
Of the 87 patients included, 42 received CBT and 45 received stress management therapy (SMT). Researchers focused on two age ranges: 13-17 and 25-45. Participants had to have early-onset OCD (<15 years) and moderate or greater symptoms at baseline.
Patients received either 12 weeks of either CBT or SMT. For the task used to activate brain activity, participants pressed one of two buttons to identify a target letter (S, K, H, and C) surrounded by four “flankers” that either mapped the same button response or the opposite response. Cues indicated how much money participants stood to lose for a right or wrong response. Participants completed four rounds of this test, each consisting of 48 trials. Performance measures included reaction times and errors. An fMRI was used to evaluate brain activity.
Both the CBT and SMT groups showed improvement over the 12-week period. The CBT group had a steeper reduction in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores compared to the SMT group (β=3.21, t=4.52, P=.001, 95% CI=4.61, 1.81)
Pretreatment brain activation within the right temporal lobe (CBT group: β=3.96, P=.003; SMT group: β=5.09, P<.001), the rACC (CBT group: β=2.68, P=.004; SMT group: β=2.94, P=0.01), and the left premotor cortex (CBT group: β=2.91, P=.002; SMT group: β=3.61, P=.008) was associated with better treatment response in CBT participants, while less activation was associated with better treatment response in the same regions in SMT participants.
Significant voxel-activation was found within a large cluster incorporating the left and right ventromedial prefrontal cortex, orbitofrontal cortex, amygdala, inferior frontal gyrus, and dorsolateral prefrontal cortex. More pretreatment activation in this region was associated with better treatment response within the CBT group β=23.91, P<.001) but a worse treatment response in the SMT group (β=5.62, P<.0.001). a similar pattern was found in the left temporal lobe.
Both age groups showed similar symptom reduction.
There were some limitations with this study. It was not possible for researchers to maintain blinded status. The researchers excluded participants with comorbidities — results may not carry over to these patients. The sample size was also moderate.
“The present study advances the field by demonstrating that associations between brain activation and treatment response were treatment specific to CBT relative to a control psychotherapy and, moreover, that these associations were stable from adolescence to mature adulthood,” the researchers concluded.
Norman LJ, Mannella KA, Yang H, et al. Treatment-specific associations between brain activation and symptom reduction in OCD following CBT: A randomized fMRI trial [published online August 28, 2020]. Am J Psychiatry. 2020;appiajp202019080886. doi: 10.1176/appi.ajp.2020.19080886