TMS for the Treatment of OCD

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TRANSLATING RESEARCH INTO PRACTICE

Rajesh R. Tampi MD, MS, DFAPA, DFAAGP, Editor

While pharmacological and therapy-based treatments have shown therapeutic efficacy in obsessive-compulsive disorder (OCD), there are many patients who have inadequate responses to these treatment modalities. Repetitive transcranial magnetic stimulation (rTMS) has shown promise for treatment-refractory affective disorders. This meta-analysis included 25 randomized controlled trials (RCTs) with 860 participants. The aim was to assess the therapeutic benefit of rTMS in patients with OCD and explored the moderators of its treatment effect.

The Study

Steuber ER, McGuire JF. A meta-analysis of transcranial magnetic stimulation in obsessive-compulsive disorder. Biol Psychiatry Cogn Neurosci Neuroimaging. 2023;8(11):1145-1155.

Study Funding

None listed.

Study Objectives

To examine the therapeutic benefit of rTMS in patients with OCD and to explore the moderators of its treatment effect.

Methodology

This meta-analysis adhered to PRISMA guidelines and included studies from 1997 to December 31, 2022. Pubmed, SCOPUS, and PsycINFO databases were searched using keywords: “obsessive-compulsive disorder,” “transcranial magnetic stimulation,” and “randomized controlled trial.” Inclusion criteria were that the study had to be an RCT that compares rTMS treatment with sham condition. In addition, the participants had to meet diagnostic criteria for OCD, and there had to be sufficient data to calculate treatment effects using psychometrically supported rating scales. The authors screened a total of 159 records for eligibility. After applying inclusion criteria, 25 studies were included with 3 trials having multiple rTMS conditions. This provided a total of 28 treatment comparisons for inclusion. The Yale-Brown Obsessive-Compulsive Scale (YBOCS) was utilized to extract effect sizes for OCD severity. If multiple depression scales were reported in the RCT, the Montgomery-Asberg Depression Scale (MADRS) was favored over the Hamilton Depression Scale (HDS) and Beck Depression Inventory (BDI). To quantify treatment effects, Hedge’s g was selected. Effective sizes were calculated using change scores. Relative risk ratios were used to calculate the treatment response and effective size.

Study Results

The random effects model found that rTMS had a moderate therapeutic effect on OCD severity when compared with sham conditions. (g=0.65, P<0.001). Significant heterogeneity was identified (P<0.003) and Egger’s test indicated that publication bias was significant (P=0.04). Further testing using the Duval and Tweedie’s trim and fill method indicated that no studies needed to be trimmed and that a moderate therapeutic effect remained (g=0.65).

For treatment response, the average rate across trials was 39.5% for rTMS and 8.8% for sham conditions. A large treatment effect of rTMS when compared with sham conditions was found using the random effects model (Relative Risk [RR] =3.15, P<0.001). There was little heterogeneity across trials (P=0.61), but publication bias was present (P=0.03). When Duval and Tweedie’s trim-and-fill method was used, rTMS continued to show a moderate effect (RR=2.67), although 4 studies had to be trimmed. There were no significant differences between trials that used > 25% improvement on the YBOCS scale compared with >30%, >35%, or >40% improvement (P=0.86).

Three treatment moderators were found to be statistically significant when analyzing heterogeneity. First, when patients had a greater improvement in depression severity, this was found to produce a larger treatment effect of rTMS on OCD (P=0.02). Second, longer TMS sessions were associated with greater improvement in OCD (P=0.05). And lastly, a lower number of TMS sessions were associated with greater improvement in OCD severity (P=0.02).

It is important to note that patient average age, sex, duration of OCD illness, concurrent use of serotonin reuptake inhibitor pharmacotherapy or antipsychotic pharmacotherapy, baseline OCD symptom severity, and/or use of medication free status were not statistically significant regarding the treatment effect of rTMS on OCD severity. Other intervention characteristics that were not found to be statistically significant included rTMS motor thresholds, rTMS frequencies, coils used for rTMS, total number of pulses used, and the location of rTMS treatment including the dorsolateral prefrontal cortex, orbitofrontal cortex, and supplementary motor area.

When looking through trial design characteristics as moderators of rTMS treatment effects, sample size, trial attrition, and year of publications were not found to be statistically significant. There was no difference between studies that used full sham conditions vs those that did not (P=0.75). Finally, there was no statistical significance between trials that used treatment refractory patients, vs nontreatment refractory patients (P=0.81).

Study Strengths

1. This review included 25 studies and 860 participants.

2. Only RCTs were included.

3. Trials included different rTMS coils, frequencies, motor thresholds, and anatomical locations.

4. There were no conflicts of interest for the authors.

Study Limitations

1. The studies included only focused on acute treatment outcomes.

2. Statistical analysis did not correct for multiple comparisons.

3. Limited patient characteristics were available for extraction across trials, such as whether exposure and response therapy had been trialed.

4. Publication bias was present.

Conclusions

This meta-analysis found that rTMS had a moderate therapeutic effect for the treatment of OCD. In addition, greater improvement in depression severity, longer TMS sessions, and fewer number of TMS sessions were moderators associated with greater improvement in OCD severity.

Practical Applications

OCD is a heterogenous disorder that can be debilitating for patients. This study shows that rTMS has moderate therapeutic effects on OCD severity.

Bottom Line

Clinicians should consider rTMS as an intervention to alleviate OCD symptoms, especially in those who have failed other treatments or those with comorbid depression.

Dr Sung is a psychiatry second year resident at Creighton University in Omaha, Nebraska. Dr Eilers is a fourth-year psychiatry resident at Creighton University in Omaha, Nebraska. Dr Schuster is a fourth-year psychiatry resident at Creighton University in Omaha, Nebraska. Dr Mullen is an assistant professor of Psychiatry at Saint Louis University School of Medicine. Dr Tampi is professor and Chairman of the Department of Psychiatry at Creighton University School of Medicine and Catholic Health Initiatives (CHI) Health Behavioral Health Services. He is also an adjunct professor of psychiatry at Yale School of Medicine, and he is a member of the Psychiatric Times editorial board.

Reference

Steuber ER, McGuire JF. A meta-analysis of transcranial magnetic stimulation in obsessive-compulsive disorder. Biol Psychiatry Cogn Neurosci Neuroimaging. 2023;8(11):1145-1155.