The main treatments for obsessive-compulsive disorder (OCD) are medications and psychotherapy. However, in some patients, symptoms may persist severely despite appropriate, long-term treatment.
In this situation, the following question may arise:
“Can OCD be treated with Gamma Knife?”
Yes, but only in selected patients with very severe, treatment-resistant disease.
Gamma ventral capsulotomy performed with Gamma Knifegamma ventral capsulotomy is an advanced treatment method that can be used in severe cases of OCD that do not respond adequately to standard treatments [1–4].
How does Gamma Knife work in OCD?
In OCD, certain brain circuits that regulate thoughts, behavior, and anxiety are thought to function differently than normal.
In Gamma Knife treatment, an area a few millimeters in size in the anterior portion of the internal capsule through which these circuits pass is targeted with great precision. The goal is to alter the functioning of neural connections associated with OCD [1].
The skull is not opened, and no electrodes or battery are placed in the brain. Gamma Knife radiation is focused on the target area, creating a small and controlled change over time.
However, this procedure is a permanent ablative treatment and is not reversible. Therefore, patient selection is very important [1].
Can it be performed in every patient with OCD?
No.
Gamma Knife is not used in patients who have been newly diagnosed or who have not yet tried standard treatments.
First, appropriate medication treatments and, in particular, exposure and response prevention (ERP) methods within cognitive behavioral therapy must have been adequately implemented.
Gamma Knife is considered only if the disease severely disrupts the person's daily life, work, education, and social relationships and severe symptoms persist despite all appropriate treatments [1,2].
Therefore, the decision should be made jointly by a team experienced in psychiatry and functional neurosurgery.
How effective is it?
Not every patient responds in the same way.
In a meta-analysis published in 2024 that included 11 studies and a total of 180 patients, approximately 60% of patients were considered treatment responders, and approximately 18% were considered to be in remission [2].
In a long-term study of 21 patients published from Turkey, a significant response was reported in 75% of patients, and remission in 35% [3].
In another series of 10 patients, a complete response was observed in 7 patients [4].
However, it should be remembered that these results are from carefully selected groups of patients with very severe disease who had been receiving treatment for years.
Does the effect begin immediately?
No.
The effect of Gamma Knife capsulotomy generally emerges over the course of months and may increase over time in some patients [1,2].
Therefore, obsessions and compulsions are not expected to disappear immediately after treatment.
Psychiatric follow-up, medication treatments, and psychotherapy when needed may continue after Gamma Knife. In fact, symptom reduction may allow psychotherapy to be applied more effectively in some patients [1].
Are there risks?
Yes.
Not opening the skull does not mean that the procedure is completely risk-free.
Side effects such as headache, temporary brain edema, mood changes, weight changes, or apathy may occur [2,3].
More rarely, delayed radiation-induced cysts or radionecrosis may develop in the target area [1,5].
In an important series of 55 patients, temporary edema requiring steroids was reported in 9% and delayed cysts in 5%. In the same study, one patient developed a serious and permanent neurological complication [5].
Therefore, Gamma Knife capsulotomy should be performed only in appropriate patients and at experienced centers.
Gamma Knife or brain pacemaker?
One of the other options for severe, treatment-resistant OCD is deep brain stimulation (DBS), or brain pacemaker treatment.
In DBS, electrodes are placed in specific areas of the brain, and the stimulation can later be adjusted or turned off. With Gamma Knife, no electrodes are placed in the brain and no open surgery is performed; however, the change created is permanent.
Therefore, which method is more appropriate varies from patient to patient.
The most important point: selecting the right patient
Perhaps the most important aspect of Gamma Knife treatment for OCD is selecting the right patient.
A person's statement that “I did not benefit from medications” alone does not mean treatment-resistant OCD. The dose and duration of the medications used, the adequacy of psychotherapy, the severity of the disease, and its impact on the person's daily life should be evaluated in detail.
Subsequently, targeting and treatment planning should be performed by a team with many years of experience in functional neurosurgery and Gamma Knife.
Conclusion
Gamma Knife can be used for obsessive-compulsive disorder; however, only in selected patients with very severe disease that is resistant to standard treatments.
Treatment is performed without opening the skull and targets, with high precision, very small areas of the brain involved in OCD circuits.
Scientific studies show that a significant reduction in symptoms can be achieved in a substantial proportion of appropriately selected patients [1–5]. However, its effect does not begin immediately, not every patient responds, and serious complications, although rare, may occur.
Therefore, Gamma Knife is not a method that replaces standard OCD treatments; it is an advanced treatment option that may be considered for severe, treatment-resistant OCD.
References
1. Miguel EC, Lopes AC, McLaughlin NCR, et al. Evolution of gamma knife capsulotomy for intractable obsessive-compulsive disorder. Molecular Psychiatry. 2019;24(2):218–240. doi:10.1038/s41380-018-0054-0.
2. Gupta R, Chen JW, Hughes NC, et al. Benefits of stereotactic radiosurgical anterior capsulotomy for obsessive-compulsive disorder: a meta-analysis. Journal of Neurosurgery. 2024;141(2):394–405. doi:10.3171/2024.1.JNS231537.
3. Peker S, Samancı MY, Yilmaz M, Sengoz M, Ulku N, Ogel K. Efficacy and Safety of Gamma Ventral Capsulotomy for Treatment-Resistant Obsessive-Compulsive Disorder: A Single-Center Experience. World Neurosurgery. 2020;141–e952. doi:10.1016/j.wneu.2020.06.098.
4. Spatola G, Martínez-Alvarez R, Martínez-Moreno N, et al. Results of Gamma Knife anterior capsulotomy for refractory obsessive-compulsive disorder. Journal of Neurosurgery. 2019;131(2):376–383. doi:10.3171/2018.4.JNS171525.
5. Rasmussen SA, Noren G, Greenberg BD, et al. Gamma Ventral Capsulotomy in Intractable Obsessive-Compulsive Disorder. Biological Psychiatry. 2018;84(5):355–364. doi:10.1016/j.biopsych.2017.11.034.