Intermittent, continuous theta burst stimulation improve compulsive behavior outcomes

Two forms of theta burst stimulation improved outcomes related to compulsive behavior, according to study results published in American Journal of Psychiatry.

“We used a single session of intermittent theta burst stimulation (iTBS) and [continuous TBS] to test competing hypotheses relevant to the development of a comprehensive pathophysiological model of compulsive behaviors in patients — namely, that increased or decreased OFC activation might be beneficial, enhancing patients’ capacity to override compulsive behaviors,” Rebecca B. Price, PhD, of the department of psychiatry at the University of Pittsburgh, and colleagues wrote.

Results of prior studies conducted among animals suggested a potential role of the orbitofrontal cortex (OFC) in compulsive behaviors; however, studies among humans have encountered limitations due to correlational designs. In the current study, Price and colleagues conducted a baseline assessment of participants and then randomly assigned 69 with compulsive behavior disorders to a session of either iTBS, which was expected to increase OFC activity, or cTBS, which was expected to decrease OFC activity, via a double-blind, between-subjects design. Both conditions targeted the left OFC with 600 pulses at 110% of target resting motor threshold. During the expected window of OFC increase or decrease, the researchers paired brain modulation in both conditions with a subsequent task that provided practice in overriding an overlearned shock avoidance behavior, which was a habit deemed clinically relevant. Further, they conducted pre- and post-TBS functional MRI of target engagement and compulsive behaviors, which were done in response to a stressful laboratory probe in an idiographic design.

Findings demonstrated modulations in OFC activation in the anticipated directions related to cTBS and iTBS. The researchers noted a beneficial effect on acute laboratory assessments of compulsive behaviors 90 minutes after TBS for cTBS, relative to iTBS, and these effects lasted 1 week after cTBS.

“Our study results advance an integrative picture of both neural and behavioral pathophysiological processes that contribute to compulsive behaviors,” Price and colleagues wrote. “Future studies would benefit from inclusion of crucial experimental controls (eg, sham TBS, cTBS without habit override) to clarify the role that behavioral context may play in leveraging an acute OFC/[frontopolar cortex] state manipulation. With further extension of these initial experimental findings, this line of inquiry could represent a first step toward developing and clinically optimizing neuromodulation therapies (eg, multisession synergistic biobehavioral treatments) that are well-grounded in basic experimental science and leverage acute neuroplasticity to maximize clinical benefit.”