A new U.K. study published in the journal Biological Psychiatry finds that patients with severe obsessive-compulsive disorder (OCD) experienced significant relief after undergoing deep brain stimulation (DBS) to one of two regions of the brain: the ventral capsule (VC) or the anteromedial subthalamic nucleus (amSTN).
Most notably, depending on which of these regions was stimulated, the technique produced distinct effects: stimulation of the VC drastically improved mood, whereas stimulation of the amSTN in the same patients improved cognitive flexibility. OCD symptoms were reduced to a similar extent regardless of which region was targeted. However, applying DBS to both sites did not appear to enhance the effects.
The findings suggest that both regions are effective DBS sites for treating OCD and that the unique brain networks targeted in each region may underlie specific symptoms of the disorder.
“This is the first study to compare directly the effects of DBS at two brain sites and has discovered important information about the brain changes in OCD responsible for obsessions and compulsions, depressed mood and cognitive inflexibility and how they might be alleviated,” said senior author Eileen Joyce, PhD, from The Institute of Neurology at University College London.
The researchers used tractography to map the brain regions activated by DBS and found that the different effects of VC and amSTN stimulation appeared to arise from the DBS adjusting different brain networks. This finding provides clues as to the roles those specific brain regions play in OCD and has potentially important implications for treatment.
“The notion that particular OCD symptom clusters might particularly benefit from stimulation of distinct brain sites raises the possibility of bringing a precision medicine approach to deep brain stimulation,” said John Krystal, MD, Editor of Biological Psychiatry.
“It also raises the question of whether multiple brain stimulation sites might be required to produce the broadest profile of efficacy,” he added. However, in the study, combined DBS of both sites did not produce substantially greater effects than either of the sites individually.
For individuals with severe OCD whose symptoms have not improved with the standard treatment methods, the findings show that DBS of VC or amSTN may be equally effective and have unique effects for specific symptoms.
“Deep brain stimulation is an emerging treatment for a small number of individuals with extremely severe OCD whose condition has not responded to multiple courses of currently available treatments such as medication or cognitive behavioral therapy,” said Joyce.
Cognitive behavioral therapy is an effective treatment for many OCD patients, but when combined with DBS in the study, it did not further enhance the symptom improvements produced by DBS.