Authors: Johanna Philipson; Matilda Naesstrom; Johannes D. Johansson; Marwan Hariz; Patric Blomstedt; Marjan Jahanshahi · Research
How Does Deep Brain Stimulation Affect Thinking Skills in Patients with Severe OCD?
Deep brain stimulation of the bed nucleus of stria terminalis appears to be a safe and effective treatment for severe OCD, with minimal cognitive side effects.
Source: Philipson, J., Naesstrom, M., Johansson, J. D., Hariz, M., Blomstedt, P., & Jahanshahi, M. (2023). Deep brain stimulation in the ALIC‑BNST region targeting the bed nucleus of stria terminalis in patients with obsessive–compulsive disorder: effects on cognition after 12 months. Acta Neurochirurgica, 165(5), 1201-1214. https://doi.org/10.1007/s00701-022-05351-2
What you need to know
- Deep brain stimulation (DBS) of the bed nucleus of stria terminalis (BNST) appears to be a safe and effective treatment for severe obsessive-compulsive disorder (OCD) that hasn’t responded to other therapies.
- After 12 months of DBS treatment, patients showed significant improvement in OCD symptoms with minimal negative effects on thinking and memory.
- DBS of the BNST may actually improve some aspects of thinking, like cognitive flexibility.
What is deep brain stimulation?
Deep brain stimulation (DBS) is a neurosurgical procedure that involves implanting electrodes in specific areas of the brain. These electrodes deliver electrical impulses that can help regulate abnormal brain activity. DBS has been used successfully to treat movement disorders like Parkinson’s disease, and is now being explored as a treatment for severe psychiatric conditions that don’t respond to standard therapies.
How was the study conducted?
The researchers studied 8 patients with severe, treatment-resistant OCD who underwent DBS surgery targeting an area of the brain called the bed nucleus of stria terminalis (BNST). The BNST is involved in fear and anxiety responses.
Before surgery and 12 months after, patients completed tests measuring various aspects of thinking and memory, including:
- Verbal and visual memory
- Attention and concentration
- Problem-solving and planning
- Mental flexibility
- Processing speed
The researchers also tracked changes in OCD symptoms using a standard rating scale called the Yale-Brown Obsessive Compulsive Scale (Y-BOCS).
What were the main findings?
Improvement in OCD symptoms
After 12 months of DBS treatment:
- 7 out of 8 patients showed meaningful improvement in OCD symptoms
- 3 patients were considered “full responders” with a ≥35% reduction in symptoms
- 4 patients were “partial responders” with a 25-34% reduction
- Only 1 patient did not show significant symptom improvement
The average Y-BOCS score (measuring OCD severity) decreased from 32.5 before surgery to 21.6 at 12 months - a substantial improvement.
Minimal negative effects on cognition
Overall, DBS treatment had very little negative impact on thinking and memory skills:
- There were no changes in overall cognitive function or major cognitive domains
- Only visual-spatial learning showed a slight decline
- Most cognitive tests showed no significant changes from before to after treatment
Potential cognitive benefits
Interestingly, patients showed improvement on one test measuring cognitive flexibility - the ability to adapt thinking and behavior in response to changing situations. This suggests DBS may actually enhance some aspects of cognition.
How did DBS affect patients’ daily lives?
Beyond the cognitive test results, the researchers noted important changes in patients’ day-to-day functioning:
- 4 patients who had been living in isolation were able to be more socially active both at home and in the community
- 1 patient was able to leave inpatient care and live more independently
- Others spent less time on compulsive behaviors, reduced self-harm, or were able to increase work hours
These real-world improvements highlight how DBS can enhance quality of life for people with severe OCD, even if the changes aren’t always captured by standardized tests.
What are the implications?
This study adds to growing evidence that DBS of the BNST region is a promising treatment option for severe, treatment-resistant OCD. Key takeaways include:
- DBS appears to significantly reduce OCD symptoms in most patients
- The treatment has minimal negative effects on thinking and memory
- DBS may even improve some aspects of cognition, like mental flexibility
- Patients experienced meaningful improvements in daily functioning and quality of life
While more research is still needed, these results suggest DBS of the BNST could be a safe and effective option for carefully selected patients with severe OCD that hasn’t responded to standard treatments.
Limitations to keep in mind
- This was a small study with only 8 patients
- There was no control group for comparison
- The study was not blinded, so placebo effects are possible
Larger, controlled studies will be important to confirm these promising early results. However, this research provides valuable long-term data on the cognitive effects of DBS for OCD.
Conclusions
- DBS targeting the BNST appears to be a cognitively safe treatment for severe OCD
- Most patients showed significant symptom improvement after 12 months
- There were minimal negative effects on thinking and memory
- Some aspects of cognition, like mental flexibility, may actually improve
- Patients experienced meaningful gains in daily functioning and quality of life