While exposure and response prevention (ERP) therapy remains the gold standard for obsessive-compulsive disorder (OCD) and is highly effective for most individuals treated with it, some people supplement it with other solutions for the best results, including medical interventions.
Typically, this approach involves oral medications that target serotonin, a chemical messenger in the brain that is often involved in OCD. For example, physicians often prescribe selective serotonin reuptake inhibitors (SSRIs) such as sertraline or fluoxetine. Again, while these medications work for many, they aren’t universally effective. Moreover, they can come with undesirable side effects that may lead some to discontinue treatment.
Because of these considerations, researchers have been exploring new biological treatments for OCD. One more promising alternative is transcranial magnetic stimulation (TMS). In 2018, the Food and Drug Administration (FDA) permitted the marketing of TMS for OCD.
As this treatment option is relatively new and radically different from the standard oral medications, people with OCD looking for alternative solutions are likely to have many questions, like how and why it works, what the treatment is like for people with OCD, what the potential side effects are, and more.
What is TMS?
TMS refers to a range of non-invasive procedures that utilize magnetic fields to stimulate neurons (small nerve cells in the brain which send and receive information). This treatment, developed in 1985, is now used for a variety of mental health and brain-related conditions, including:
- Treatment-resistant depression
- Smoking cessation
How does it work?
TMS relies on two interrelated forms of energy to impact how our brains function: electricity and magnetism. Specifically, TMS machines contain a magnet that generates a rapidly changing magnetic field, which produces electricity when brought near something that conducts it.
Why does this allow TMS to affect our brains? The reason is that neurons rely on electrical activity to send and receive information. When neurons fire, electrical activity flows from one end down to the other. This results in the release of neurotransmitters (chemical messengers in the brain) which relay information to other neurons.
Because neurons are electrically active, magnetic fields can alter their activity or cause them to fire. That’s the first step in how TMS can impact how your brain functions. When the magnetic coil generates a magnetic field placed on top of the scalp in the intended location, it causes neurons in a particular part of the brain to fire or generate electrical impulses.
During a treatment session, the magnetic field is turned on and off rapidly, causing neurons in the targeted area to engage in various patterns of activity. This changes how these neurons are likely to fire after treatment is over, and can even strengthen or weaken their connections with other parts of the brain. When TMS targets parts of the brain associated with mood, anxiety, and decision-making, it can alter how they work and improve mental health conditions associated with dysfunction in those brain regions.
Is TMS the same as electroconvulsive therapy?
Electroconvulsive therapy (ECT) is another non-invasive procedure that has been used to treat psychiatric conditions like anxiety and depression. During a round of ECT, patients are put under anesthesia, and an electrical current is passed throughout the brain to induce a seizure. Though its exact mechanism of action is unknown, ECT has been used to treat depression quickly, as well as other conditions such as mania in people with bipolar disorder and schizophrenia.
Though TMS may share a superficial similarity to ECT, the two treatments are dramatically different. In particular:
- TMS does not send electricity into the brain
- TMS is not designed to induce a seizure
- TMS does not require general anesthesia
- TMS is not associated with memory loss or other cognitive impairments sometimes associated with ECT
- TMS is much more localized, targeting specific areas of the brain associated with OCD and other mental health conditions
What is TMS for OCD?
OCD is a mental health condition characterized by obsessions and compulsions. Obsessions are persistent and recurring thoughts, images, and urges that are experienced as intrusive and cause significant distress. Compulsions are mental or physical acts performed in response to obsessions in an attempt to alleviate anxiety and distress or prevent an unwanted outcome. OCD affects around 1 in 40 adults in their lifetime, worldwide.
After the FDA permitted the marketing of TMS for depression, researchers began exploring whether it might be helpful for other mental health conditions. In the process, they discovered that it could alleviate the symptoms of OCD, and after extensive research, TMS was approved for the condition in 2018.
When it comes to treating OCD with TMS, there are several different methods and approaches that have shown to be effective in research studies. Different settings and factors include the type of machine, the targeted brain location, the frequency of the magnetic pulses, and whether to pair treatment with symptom provocation.
When it comes to locations of treatment, rTMS, a type of TMS that targets areas of the brain usually near the surface, typically focuses on eithera variety of areas the dorsomedial prefrontal cortex (dmPFC), pre-supplementary motor area (pre-SMA), orand bilateral and right dorsolateral prefrontal cortex (dlPFC). In another type of TMS called deep TMS or dTMS, practitioners target deeper brain regions of the anterior cingulate cortex (ACC) and dmPFC.
TMS for OCD differs from its use in other mental health conditions, such as depression, in that a tested strategy using dTMS involves triggering some of the condition’s main symptoms. The logic is that, as with exposure and response prevention (ERP) therapy, provoking some degree of distress may result in stronger therapeutic outcomes.
Though a variety of protocols are used, it’s worth noting that when the FDA permits the marketing of TMS for a particular condition, they do so for specific combinations of machines and protocols. When it comes to TMS for OCD, the FDA permitted the marketing of it for:
- A dTMS device, specifically either the BrainsWay, dTMS H7 coil, or the MagVenture cool DB80 coil devices
- Using high-frequency stimulation (20 Hz)
- Targeting the dmPFC or ACC
With that said, this does not mean that other experimental strategies are illegal or unsafe. However, they may not have been evaluated by the FDA and are less likely to be covered by insurance.
What’s it like to receive TMS for OCD?
Patients receiving TMS will go into their doctor’s office several times a week for multiple weeks to complete their treatment.
During each session, the technician will place the machine in the correct location and dial in the appropriate parameters. Next, they will initiate the treatment, which generally lasts around 20-30 minutes.
So what does the treatment feel like? As the session proceeds, patients typically feel a light tapping on their scalp. Some report pain or discomfort, though this can often be fixed by changing the setup.
In contrast to other interventions, such as ketamine or ECT, TMS is generally associated with little to no after-effects, and patients are free to leave as soon as a session ends.
What are the advantages of TMS for OCD?
As opposed to other medical interventions for OCD, particularly oral medications, TMS carries a few potential advantages.
#1 More targeted effects
The primary benefit results from the fact that, at least in theory, TMS can deliver a more targeted solution by focusing on particular areas of the brain that are believed to be associated with or causally responsible mental health symptoms. While oral medications may target specific neuron types or receptors, they are delivered throughout the brain and even some other areas of the body.
#2 More prolonged effects
When it comes to oral antidepressants, patients often have to keep taking the medication for as long as they want to receive the benefit. With TMS, therapeutic effects can last long after treatment has ended. For example, in the case of treatment-resistant depression, studies have found that a significant proportion of individuals who benefited from initial TMS treatment maintained a full remission six months later. Results for the durability of TMS for OCD have been somewhat more variable, ranging from two weeks to three years.
What are the side effects?
Despite being non-invasive and highly targeted, TMS can still present risks. Some of the more common side effects include:
- Scalp pain
- Neck pain
- Facial twitching
- Altered cognition during treatment
Serious side effects are rare but possible. In particular, TMS can cause seizures (mainly for high-frequency rather than low-frequency stimulation) and a low risk of mania in individuals with bipolar disorder.
How effective is TMS for OCD?
Studies on the effectiveness of TMS for OCD appear to vary, perhaps due to researchers using a diverse array of machines, frequencies, target regions, and more. As a result, it is difficult to provide an overall estimate of the efficacy of TMS. With that said, a 2021 meta-analysis of 26 randomized controlled trials with 761 patients found TMS to be more effective than placebo TMS. However, the average response and remission rates were not reported. Another recent study conducted by Brainsway, a manufacturer of dTMS devices, found that after 29 sessions, around 57 percent of patients achieved at least a 30 percent reduction in their OCD symptoms.
Is TMS a replacement for ERP?
TMS may be a good alternative for those who have not responded well enough to ERP or medications. However, TMS should not be considered a replacement for ERP in people starting OCD treatment, as evidence holds that ERP and medications should be first-line treatments.
Some may also wonder if TMS should be combined with ERP. When dTMS treatment is paired with symptom provocation, a recent analysis found that distress during symptom provocation—but not between-session habituation or progression on one’s hierarchy of distressing triggers—was associated with better TMS response. However, it’s important to note that symptom provocation by itself is not the same as ERP, as these are not true exposures that one practices every day, and that this model of symptom provocation does not involve response prevention.
In fact, experts do not yet know if the combination of TMS and ERP is a) more beneficial than either intervention alone, b) the same as doing either alone, or c) potentially worse than doing either alone. This has not been examined in research studies nor has it been studied in people receiving usual clinical treatment. Thus, one may instead consider trying ERP first, and then trying TMS if it is not effective (sequentially), or vice-versa if one happens to receive TMS first. Anyone who is interested in trying TMS treatment for OCD should first consult with a licensed clinician who has received specialty training in OCD treatment.