6 min read

David Veale, South London and Maudsley NHS Trust and the Nightingale Hospital.

1/1/2025

At the time of writing, repetitive Transcranial Magnetic Stimulation (rTMS) and transcranial Direct Current Stimulation (tDCS) are still being researched as treatments for OCD.

rTMS may help to reduce over-activity in the brain and the benefits in OCD may be modest. tDCS has less evidence for treating OCD. Both rTMS and tDCS are not available as treatments in the NHS for OCD, but some private clinics may offer them. rTMS is more established for treating depression (but not depression in the context of OCD). It’s important to note that there is no “magic bullet” for OCD, and treatment often involves a combination of approaches. I shall discuss first rTMS then tDCS.

Repetitive Trans-Cranial Magnetic Stimulation (rTMS)

rTMS may offer modest benefits for OCD, but the long-term effects or how often it may need to be used are not known.

How rTMS is used

rTMS involves using electromagnetic pulses on the skull to stimulate brain cells. Typically, you are awake and sit in a chair, while a technician places a small coil over the frontal region of your skull. For OCD, a ‘Figure of Eight’ coil or a helmet that reaches deeper regions of the brain is used – this is different to the type of coil used in depression. The treatment in OCD lasts about 30 minutes per session and is done five times a week for 4-6 weeks (20-30 sessions).

A different coil is used for treating depression as it is attempting to re-establish the balance between the left and right hand side of the brain. rTMS is more established in treating depression. It has also been used experimentally in treating PTSD and cocaine dependency.

Effectiveness

The NICE guidelines in 2020 suggested rTMS required more research (https://www.nice.org.uk/guidance/ipg676). A recent analysis of all studies conducted in rTMS (Pellegrini et al., 2022) showed that there was some beneficial effect of rTMS compared to a sham treatment in OCD (https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4065288).

They found rTMS may be most effective for people who have not yet tried a SSRI or have only used one SSRI. On average about 40% will make significant improvements. A SSRI is the most effective medication for OCD and includes sertraline, escitalopram or fluoxetine. rTMS may not therefore be helpful for people who have already tried 2 or more SSRIs or augmentation (e.g. risperidone or aripiprazole). This aligns with my experience of individuals with severe OCD who have had SSRIs and CBT and then tried rTMS and it did not have any clear benefit. However, there are exceptions. One can usually tell if the rTMS will have benefit in the first two weeks after treatment has begun. If it is having no benefit then it’s reasonable to discontinue.

There have been no direct comparisons of rTMS to CBT or combined treatments of rTMS with CBT. CBT is not always optimally delivered, or you may not have been ready to change and so it is difficult sometimes to know whether you have had an adequate trial of CBT. It is not known how to best treat severe depression in the context of OCD. In addition, the long term effectiveness of rTMS in OCD is not known.

Side Effects of rTMS

About 10% of people get some local discomfort over the area where the rTMS is applied. Some people might get a headache for a short period after the stimulation treatable by paracetamol). Serious side effects like seizures are rare (around 2 in 1000).

Cost

The cost in a private clinic in the UK such as the Nightingale is about £180 a session or £900 a week. So, if you had it for up to 6 weeks, the cost is about £5400. There are other providers for the cost is similar. Some medical insurers may cover the cost. However, beware sometimes after making a claim for rTMS I am told that some insurers deem you to have chronic condition and exclude you from further benefit in treating OCD.

Transcranial Direct Current Stimulation (tDCS)

tDCS involves electrical stimulation of the brain by applying a weak direct current to the scalp by a handheld device. It is used for treating mild depression. It has less research in OCD than rTMS with only one or two trials showing some benefit. It needs more research, and I suspect it is likely to be helpful for only mild to moderate OCD as an alternative to medication or CBT.

How tDCS is used

When you have tDCS, you remain awake and alert. You are usually seated while a portable battery-operated device delivers a constant low-strength direct current to 2 electrodes placed on the scalp. The treatment lasts about 20-30 minutes per session and is typically repeated daily for several weeks. It can be administered in a clinic or even at home with a personal device.

Effectiveness and Side Effects

The side effects are usually mild, such as a burning sensation, skin redness, headaches or itching. The “Flow” is the most common device and can be purchased online for around £400 (https://tdcsdevices.com/tdcs-devices-uk/). The manufacturers highlight that these are not certified for OCD treatment and are primarily for treating depression. I am not aware of it being available on the NHS for treating OCD or depression.

Conclusion

In conclusion, while rTMS and to a lesser extent tDCS offer potential treatments for OCD, they should not replace treatments like CBT or SSRIs. If you are considering rTMS, I would not recommend it until you have had at least one good trial of quality CBT. The best way of thinking about is as an alternative to taking a SSRI. Always discuss these options with your doctor to determine what might be most appropriate for your specific case.

David Veale