In a recent study published in the Journal of Neurology, Neurosurgery & Psychiatry, researchers investigated the effectiveness of deep brain stimulation (DBS) against treatment-resistant obsessive-compulsive disorder (OCD).

OCD is characterized by intrusive, enduring obsessive thoughts and dysfunctional, ritualized behaviors. The illness typically manifests during a crucial developmental stage, such as puberty, early adulthood, or childhood. Ablative lesioning techniques like anterior cingulotomy and anterior capsulotomy are well-known surgical approaches to treat symptoms of treatment-resistant OCD (TROCD). More extensive knowledge of treatment efficacy across studies with various methodological methods is necessary for the developing field of DBS for TROCD.

Review: Efficacy of deep brain stimulation for treatment-resistant obsessive-compulsive disorder: systematic review and meta-analysis. Image Credit: Ralwell / Shutterstock

About the study

In the present study, researchers evaluated the effectiveness of DBS in reducing OCD and concomitant depressive symptoms across patients with TROCD by employing a systematic review and meta-analysis.

The Systematic Reviews and Meta-Analyses (PRISMA) standards were followed to produce a systematic review. Studies were investigated if they satisfied the following requirements: (1) the subjects were adults aged above 18 years with a primary OCD diagnosis as per the International Classification of Diseases criteria or the Diagnostic and Statistical Manual of Mental Disorders Fourth or Fifth edition (DSM-IV or DSM-V), (2)  used the Yale-Brown Obsessive Compulsive Scale (Y-­BOCS) to measure the outcome (3) DBS was the primary intervention, (4) primary outcome was the improvement in OCD symptoms post-DBS treatment, (5) treatment response defined as 35% or higher reduction in Y-BOCS score, and (6) published in peer-reviewed journals in the English language.

Using the R statistical computing package, a meta-analysis was conducted. The primary outcomes included Y-BOCS mean difference at the most recent follow-up compared to baseline, treatment effect or Y-BOCS percent decrease at the most recent follow-up, and responder rate at the most recent follow-up. Two secondary objectives were the depression scale responder rate and the standardized mean difference (SMD) in depression scale scores.

Results

A total of 3,023 records, spanning the years 1986 to 2021, were found using the search strategy. Thirty-four studies from 2005 to 2021 were chosen for the systematic review and meta-analysis, including nine randomized controlled trials (RCTs). All 352 individuals were adults with severe to extreme OCD at the beginning of the study. The studies had had three first-line pharmacotherapy trials, one supplemental medication trial, and at least 20 hours of expert exposure and response prevention (ERP) without a persistent response to treatment. Additionally, patients in 67% of the studies had to have an unremitted disease of five years or more before being considered for surgery. Among the 11 studies remaining, only one required over ten years of disease duration and two years or more of unremitted disease; another required one year of unremitted disease, while five did not specify.

The team noted that the disease lasted an average of 24.3 years. According to 23 studies, major depressive disorder affected about 55% of patients, anxiety disorders affected 10% of people, and personality disorders affected 9.5% of people. RCTs had a median of 10 participants, compared to seven in non-RCTs. The two stimulation targets that were most frequently discussed were ventral capsule/ventral striatum (VC/VS) and nucleus accumbens (NAc), followed by anterior limb of the internal capsule (ALIC), bed nucleus of stria terminalis (BNST), and ALIC/BNST.

Using the Hamilton depression scale was utilized in 14 investigations. To evaluate depression before and after surgery, seven studies used the Beck Depression Inventory (BDI), five studies used the Montgomery-Åsberg Depression Rating Scale (MADRS), and one study used the Depression Anxiety Stress Scale-Depression (DASS-D). A Hamilton anxiety scale was employed in 11 of the 16 studies that provided anxiety ratings, the STAI-X1/2 in four of 16, and the DASS-A in 1.46 of 16.  Seven of the seventeen studies that provided GAF ratings did so exclusively with baseline data.

About 70% of studies provided comprehensive information on serious adverse events (SAEs), including but not limited to hardware issues, infections, seizures, suicide attempts, intracranial hemorrhage (ICH), and the emergence of de novo obsessions linked to stimulation. Overall, 31% of patients reported having at least one SAE. There were 8% or fewer device-related problems, such as lead damage or misposition. There were nine postoperative seizures and 11 occurrences of postoperative infection, of which six needed the removal and/or replacement of a pulse generator. One patient had a generalized tonic-clonic seizure, an intracranial infection, shock, and a drug-induced coma, among other SAEs.

Furthermore, there were six instances of attempted suicide and one suicide that was successful. Studies documented five postoperative ICH occurrences, two of which led to protracted finger palsy and prolonged dysarthria. In two instances, DBS therapy itself resulted in a new obsession (such as checking the settings and battery life), which aggravated OCD.

The meta-analytical Y-BOCS mean difference (MD) among 345 patients pooled from 31 trials was 14.28 points at the most recent follow-up. The meta-analytical treatment effect (TE) was discovered to be a 47% decrease in Y-BOCS scores at the last follow-up across 249 patients from 28 studies where precision estimates could be acquired or measured using the pre-disambiguated and post-disambiguated data that was available.

Conclusion

The study findings showed that DBS is a successful treatment for TROCD, and the typical patient will get a 50% reduction in OCD symptoms. With further follow-up, two-thirds of patients will experience at least a complete response to DBS therapy. In addition, the researchers believe that current limbic and non-limbic targets can be stimulated to reduce comorbid depressive symptoms in TROCD significantly.

Written by

Bhavana Kunkalikar

Bhavana Kunkalikar is a medical writer based in Goa, India. Her academic background is in Pharmaceutical sciences and she holds a Bachelor's degree in Pharmacy. Her educational background allowed her to foster an interest in anatomical and physiological sciences. Her college project work based on ‘The manifestations and causes of sickle cell anemia’ formed the stepping stone to a life-long fascination with human pathophysiology.