Transcranial Magnetic Stimulation for Depression + OCD

Written by: David Safani, MD, MBA, DFAPA, DFAACAP – Medical Director, The Mental Health Collective – Newport Beach, CA

Treatment resistance is common, not rare. About a third of people with major depression do not get well after trying several antidepressants, and many people with obsessive-compulsive disorder still have symptoms that interfere with daily life even after a full course of an SSRI at a proper dose.

For a long time, the options at that point were limited. Transcranial magnetic stimulation (TMS) has widened them considerably. What follows is an overview of the treatment, the evidence behind it, and the reasoning behind how it is delivered on site at The Mental Health Collective.

What TMS Is — and What It Is Not

TMS sends a focused magnetic pulse through a coil held against the scalp. The pulse creates a small electrical current in a specific area of the brain involved in mood and thinking. For depression, the target is the left dorsolateral prefrontal cortex, an area of the frontal lobe repeatedly linked to depression in imaging research.

TMS is often confused with electroconvulsive therapy, and the difference is worth stating plainly. TMS uses no anesthesia and no sedation, and it does not cause a seizure. Patients stay awake and alert during the session and need no recovery time afterward. It does not cause the memory or thinking problems associated with ECT.

The contrast with medication is just as important. Antidepressants travel through the bloodstream to the whole body, which is why side effects like weight gain, sexual side effects, drowsiness, and stomach upset are so common — and why so many people stop taking them. TMS acts on specific brain circuits instead, so its side effect profile is quite different. The most common complaints are scalp discomfort where the coil sits and headache, and both usually fade within the first week.

The likely mechanism involves neuroplasticity — the brain’s ability to strengthen and reorganize its own connections. Repeated stimulation seems to shift circuit activity gradually, across many sessions, rather than all at once. That is why TMS is given as a daily course over several weeks instead of as a single procedure.

The Evidence for Depression + TMS

TMS has been FDA-cleared for major depression since 2008, and the evidence has continued to build since then. The American Psychiatric Association identifies TMS as an effective and well-tolerated treatment for patients with major depression who have not responded well enough to medication.

This is worth saying because TMS is still sometimes described as experimental. It has been tested in large, multi-site trials in which neither the patient nor the rater knew who received real stimulation and who received a placebo version — the same standard applied to medications. Those trials show that a meaningful share of patients who failed several medications respond to TMS, and a smaller but real share recover fully. The clearance has since been extended to anxious depression, meaning anxiety symptoms that occur alongside major depression, which is a very common and often undertreated presentation.

The limits deserve equal honesty. TMS does not work for everyone, and no clinician can promise a particular result. What can fairly be said is that for someone who has already failed several medication trials, the odds with TMS compare well to the odds of responding to the next medication on the list.

Why Precise Targeting Matters

TMS works on a specific spot, which means results depend on where the pulse actually lands. This is an underappreciated source of variation in outcomes, and it is one of the places where practices differ most.

For years, the frontal target was located using the “5 cm rule” — measuring a set distance forward from the spot on the scalp that produces a thumb twitch. Because head size and brain shape vary quite a bit from person to person, this rule of thumb misses the intended target in a fair number of patients, sometimes landing over a neighboring region with a different job entirely. Newer scalp-measurement methods improve on this, but they are still estimates based on outside landmarks.

The TMS service on site uses the Localite optical navigation system. In a workflow that does not require an individual MRI, the system takes a standard reference brain model and scales it to the patient’s own head using measured landmarks, then tracks both the coil and the patient’s head in real time with infrared cameras. The target is defined by anatomical coordinates rather than estimated with a tape measure. Published studies of navigated targeting without MRI report accuracy within a few millimeters and better results than scalp measurement alone.

Several practical benefits follow, and they add up over a full course of treatment:

• The target stays the same from session to session. A standard course runs thirty or more sessions over six to nine weeks, often with more than one technician running them. Without navigation, small differences in placement add up into drift away from the target. With navigation, the target is set once and returned to at every session, and the screen shows coil position, angle, tilt, and distance from the scalp in real time — all of which affect how much energy reaches the brain.
• Dosing is more accurate. Stimulation strength is set as a percentage of each patient’s own motor threshold, which is measured by finding the spot that produces a thumb twitch. Navigation helps locate that spot precisely, which makes the dose itself more accurate — not just the location.
• The work is documented. Targeting settings are recorded rather than recalled. If a patient is not improving as expected, it becomes possible to review what was actually delivered and tell the difference between a treatment that was not right for that patient and one that was not delivered accurately.
• Specific published coordinates can be used. Navigation makes it possible to aim at coordinates identified in the research literature rather than at an anatomical estimate. This matters because studies have found that outcomes relate to exactly which part of the frontal lobe is stimulated and how it connects to deeper mood-related structures.
• There is a clear path to imaging-guided treatment. The same system can also work from an individual’s structural MRI or functional MRI scan. Building the workflow on navigation now means personalized, scan-guided targeting can be added later without replacing equipment or retraining the team.

Obsessive-Compulsive Disorder + TMS

TMS was first cleared for OCD in 2018, and the cleared indication now includes figure-of-eight coils. The MagVenture system in use here is cleared for OCD with a figure-of-eight coil, aimed at the dorsomedial prefrontal cortex on both sides — a midline area of the frontal lobe that sits within the brain loop most closely tied to obsessions and compulsions.

This target is worth connecting back to the previous section. It sits on the midline, where there is no convenient scalp landmark to measure from, and it lies close to regions with very different functions. It is exactly the kind of target navigation was built for.

The results in hard-to-treat OCD are meaningful. In the multi-site trial behind the original OCD clearance, 38% of patients receiving real stimulation improved enough to meet response criteria, compared with 11% of those receiving the placebo version, and the benefit held up a month after treatment ended — in a group that had already failed medication.

The Role of Exposure and Response Prevention

One detail from the OCD research deserves far more attention than it usually gets.

In that trial, patients did not simply sit down and receive stimulation. Before every session, each patient went through a brief, personalized symptom provocation — a structured exposure to that person’s own obsessive triggers, dialed in to bring their distress to a specific level. The reasoning is mechanical: stimulating a circuit that is switched on appears to work differently than stimulating one that is quiet. The protocol was built as exposure plus stimulation, not stimulation alone.

That procedure is exposure and response prevention, delivered in the minutes before treatment.

This makes the skill of the therapy team a clinical factor, not a marketing one. Doing provocation well takes a clinician who knows the different forms OCD takes, can build an accurate and personal list of triggers ranked by distress, can spot mental rituals and reassurance-seeking that are invisible from the outside, and can hold a patient at a useful level of distress without letting them slip into avoidance. Done by an untrained technician reading from a generic list, it becomes a box to check rather than real treatment.

This fits the wider treatment literature in any case. ERP remains the best-supported therapy for OCD, and no course of stimulation replaces it. Patients treated on site have access to the highly skilled ERP therapists at The Mental Health Collective, who conduct exposure work as real clinical treatment and carry the same personalized trigger list into therapy across the rest of the week. The exposure work around a TMS session and the ERP done in therapy that afternoon belong to one plan, rather than sitting side by side as unrelated services.

Combining TMS with Other Treatment

There is a strong clinical case for pairing TMS with psychotherapy. If TMS opens a window in which the brain is more able to change, the value of that window depends a great deal on what happens inside it. Changing behavior, building tolerance for distress, and revising the beliefs that depression and OCD install are how gains get consolidated and held.

TMS is therefore offered for patients enrolled at The Mental Health Collective, delivered on site alongside their residential or day program. 

Who Is a Candidate for TMS?

TMS is worth considering for patients with major depression or OCD who have not responded well enough to medication and therapy, and for patients whose medication side effects have made it impossible to reach an effective dose.

It is not right for everyone. Metal or implanted devices in or near the head rule it out. A personal or family history of seizures, a significant head injury, or medications that raise seizure risk all call for careful review, since TMS carries an extremely small seizure risk. Active psychosis, bipolar disorder, and ongoing substance use change the picture and need to be worked into the overall plan rather than treated as automatic disqualifiers.

Deciding on candidacy is a psychiatric evaluation, not a screening form. Referring clinicians and prospective patients are welcome to start that conversation directly with a psychiatrist experienced in this treatment.

References

1. American Psychiatric Association. Position Statement on Transcranial Magnetic Stimulation (TMS). Washington, DC: APA.
2. U.S. Food and Drug Administration. 510(k) Premarket Notification K193006 (MagVenture TMS Therapy System) — clearance for adjunct treatment of obsessive-compulsive disorder, August 2020.
3. Tendler A, Roth Y, Zangen A. Symptom provocation for treatment of obsessive-compulsive disorder using transcranial magnetic stimulation: a step-by-step guide for professional training. Frontiers in Psychiatry. 2021;12:735300.
4. Herwig U, Padberg F, Unger J, et al. Transcranial magnetic stimulation in therapy studies: examination of the reliability of “standard” coil positioning by neuronavigation. Biological Psychiatry. 2001;50(1):58–61.
5. Weigand A, Horn A, Caballero R, et al. Prospective validation that subgenual connectivity predicts antidepressant efficacy of transcranial magnetic stimulation sites. Biological Psychiatry. 2018;84(1):28–37.

TMS services described here are provided on site at The Mental Health Collective by an independent psychiatric medical practice. 

This article is for educational purposes and is not individualized medical advice. Treatment decisions should be made in consultation with a licensed psychiatrist.