# Are You a Candidate for TMS? Eligibility, Contraindications, and the Safety Screen A patient is generally considered a candidate for transcranial magnetic stimulation (TMS) for depression when three conditions are met: a confirmed DSM-5-TR diagnosis of **major depressive disorder**, **inadequate response to two or more antidepressant trials** at therapeutic dose for at least six weeks each within the current episode, and **no contraindications on the safety screen**. This article walks through each condition in clinical terms, lists the absolute and relative contraindications a treating psychiatrist evaluates before clearing a patient for treatment, and clarifies several common patient worries — tattoos, dental fillings, current SSRI use — that are not, in fact, disqualifying. The intent is patient and family literacy; final candidacy is determined by the treating clinician at consultation. ## Condition 1 — A DSM-5-TR diagnosis of major depressive disorder TMS is FDA-cleared for major depressive disorder (MDD) — not for "feeling down," demoralization, bereavement, or transient sadness. Clinically, MDD is defined in the *Diagnostic and Statistical Manual of Mental Disorders*, Fifth Edition, Text Revision (DSM-5-TR) as the presence of at least five of nine symptoms — depressed mood, anhedonia, weight or appetite change, sleep disturbance, psychomotor agitation or retardation, fatigue, worthlessness or excessive guilt, impaired concentration, and recurrent thoughts of death or suicide — present for at least two weeks and producing meaningful impairment in social, occupational, or other important areas of functioning.[^dsm-5-tr] At least one of the five symptoms must be depressed mood or anhedonia. This diagnosis is established at consultation through structured psychiatric interview, validated rating scales (most commonly the **PHQ-9**), and review of prior treatment records. Either a single episode or recurrent MDD qualifies. Persistent depressive disorder, MDD with seasonal pattern, and peripartum depression also generally qualify when the active episode meets full MDD criteria. Bereavement-only presentations and adjustment disorder with depressed mood do not. The DSM-5-TR boundary matters because TMS treats a specific pathophysiology — left dorsolateral prefrontal cortex hypoactivity and its network connections — that is not present in every patient who feels depressed. Diagnostic precision is the first step of candidacy. ## Condition 2 — Inadequate response to prior antidepressant medication The second condition is the **treatment-resistance** threshold. Most payer policies and the broader clinical consensus require documented inadequate response to at least two antidepressant trials of **adequate dose** and **adequate duration** within the current depressive episode — typically a minimum of six weeks at therapeutic dose for each medication.[^gaynes-2020] An "adequate trial" is a clinical term of art: a sub-therapeutic dose discontinued at two weeks does not count, even if it was prescribed. The regulatory anchor for this language sits in the FDA clearances. The original NeuroStar 510(k) clearance under **K061053** (2008) covered adult MDD "after the failure of at least one prior antidepressant medication at or above the minimal effective dose and duration in the current episode."[^fda-neurostar] Most commercial payer policies and Medicare Administrative Contractor Local Coverage Determinations subsequently tightened the threshold to **two failed trials**, which is now the de facto coverage standard.[^cms-lcd-tms] The American Psychiatric Association Practice Guideline for the Treatment of Patients with Major Depressive Disorder describes neuromodulation — including TMS — as a reasonable option for patients who have not achieved remission after sequential pharmacotherapy.[^apa-mdd] This is consistent with the STAR*D evidence that the incremental benefit of each additional medication trial diminishes after the second step.[^star-d] For patients without a complete treatment-history record, the clinic typically requests a **treatment-history letter** from the prior prescribing psychiatrist or primary care physician. Where prior records are not retrievable, the candidacy consultation may include a structured retrospective interview to reconstruct the trial history. ## Condition 3 — The safety screen (contraindications) The third condition is the safety screen — the part of candidacy designed to prevent harm. Contraindications fall into three categories: absolute, relative, and common worries that are not actually contraindications. ### Absolute contraindications For TMS for depression, the principal absolute contraindication is **non-removable ferromagnetic metal in or near the head**. The magnetic field can heat ferromagnetic material and induce currents in conductive implants. Items that disqualify a patient from standard rTMS include:[^perera-2016][^rossi-2021] - Cochlear implants - Cerebral aneurysm clips or coils - Deep brain stimulator (DBS) electrodes - Vagal nerve stimulator (VNS) leads in the cervical region near the coil's field - Certain intracranial stents and shunts with ferromagnetic components - Retained ferromagnetic shrapnel or bullet fragments in the head or upper neck The treating clinician verifies implant composition with the implanting surgeon's records or the device manufacturer's MR-compatibility documentation before clearance. ### Relative contraindications (case-by-case clinical judgment) Several conditions require careful screening but are not automatic disqualifications. The treating psychiatrist weighs risk and benefit individually: - **History of seizure or seizure disorder** — the single largest risk factor for TMS-induced seizure, which is otherwise estimated at fewer than 1 per 60,000 sessions when published safety guidelines are followed.[^lerner-2019][^rossi-2021] Pre-treatment EEG is **not** standard practice; clinical history and medication review are. - **Active substance use disorder**, particularly alcohol use disorder with active withdrawal risk. Alcohol withdrawal lowers seizure threshold; treatment is typically deferred until withdrawal stabilization is documented. - **Current pregnancy.** Safety data in pregnancy are limited. Some clinicians proceed in carefully selected cases where the maternal risk of untreated depression is judged greater than the unknown risk of stimulation; others defer until postpartum. This decision is made jointly with the patient and the obstetric team. - **Bipolar I disorder without a mood stabilizer.** Induced-mania rates with TMS are low and the magnitude of the risk is debated, but the consensus is to require concurrent mood-stabilizer therapy in patients with a bipolar I history before stimulating the left DLPFC.[^xia-2008] - **Implanted medication pumps, pacemakers, or implantable cardioverter-defibrillators (ICDs).** Most devices below the neck are not in the coil's field, but each is a case-by-case clinical decision in coordination with the implanting service. ### What is *not* a contraindication Several common patient worries are not, in clinical practice, disqualifying: - **Standard tattoos** — including those on the head and neck. The exception is the rare ink containing iron-oxide pigment located **at the stimulation site itself**; this is reviewed at consultation. - **Dental fillings, crowns, bridges, retainers, and orthodontic implants.** Dental restorations sit below the coil's effective field and do not interfere with stimulation. - **Most surgical clips below the skull base.** - **Current SSRI or SNRI use.** Almost all patients arrive on a stable antidepressant regimen at intake. TMS is typically delivered concurrently with ongoing pharmacotherapy. - **Anti-anxiety medications** within reason. High-dose benzodiazepines can raise the seizure threshold and modestly blunt response; the treating clinician reviews the regimen but does not categorically exclude these patients. ## What a candidacy consultation actually looks like A first-visit candidacy evaluation typically covers the following, in sequence: 1. **History intake** — medical, psychiatric, surgical, medication, family, and substance-use history; review of implanted devices and metallic-implant questionnaire. 2. **Rating scales** — PHQ-9 at minimum; PHQ-9, GAD-7, and Columbia-Suicide Severity Rating Scale (C-SSRS) in most clinics; PHQ-9 is re-administered weekly during treatment to track response. 3. **Treatment-history review** — confirmation of two or more adequate antidepressant trials in the current episode, with dose and duration documented. 4. **Insurance verification and prior authorization** — submitted in parallel with the clinical evaluation, since most commercial-payer and Medicare coverage requires prior authorization with documented trial failures (more on the [insurance verification process](/insurance/verify/) and the prior-auth workflow). 5. **Motor-threshold mapping** — performed at the first treatment session, not at the candidacy consultation. The motor threshold confirms that cortical excitability is within the expected range and sets the per-patient stimulation dose. This is the second, physical screen — a patient who cannot generate a measurable motor evoked potential within the stimulator's output range is identified at this step. A separate eligibility framework applies to **OCD candidacy.** Deep TMS for adult obsessive-compulsive disorder uses a different coil geometry, a different cortical target (medial prefrontal and anterior cingulate cortex), and a different prerequisite pathway — typically an inadequate response to an adequate SSRI trial plus exposure-and-response-prevention therapy. The relevant clearance is BrainsWay's 510(k) under **K183303** (2018). The dedicated [TMS for OCD article](/blog/tms-for-ocd-fda-cleared-deep-tms-protocols/) covers candidacy in that pathway. ## Key takeaways - TMS candidacy for depression rests on three conditions: a **DSM-5-TR MDD diagnosis**, **two or more failed antidepressant trials** in the current episode at adequate dose and duration, and a **clear safety screen**. - The **absolute contraindication** is non-removable ferromagnetic metal in or near the head — cochlear implants, aneurysm clips, DBS electrodes, retained shrapnel. - **Relative contraindications** (case-by-case): seizure history, active substance use, pregnancy, untreated bipolar I, certain implanted devices. - **Not contraindications**, despite frequent patient concern: standard tattoos, dental fillings, current SSRI/SNRI use, anti-anxiety medications within reason. - Final candidacy is determined at clinical consultation, with **motor-threshold mapping** at the first session as the second physical screen. Most patients in Anaheim and Orange County who arrive on a page like this end up self-screening their own candidacy as they read. If the three conditions above appear to fit — and none of the absolute contraindications apply — the next step is short. The clinic's [TMS questionnaire](/tms-questionnaire) is a five-minute pre-screen our psychiatrists review before a formal consultation, and the [insurance verification](/insurance/verify/) workflow runs in parallel so the financial picture is clear before any treatment is scheduled. For background on the treatment itself, the [TMS therapy](/services/tms-therapy/) service page covers protocol, course length, and what a session looks like in the chair. ## Sources / Further reading [^dsm-5-tr]: American Psychiatric Association. *Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR)*. American Psychiatric Publishing; 2022. Major Depressive Disorder diagnostic criteria. [^gaynes-2020]: Gaynes BN, Lux L, Gartlehner G, et al. Defining treatment-resistant depression. *Depression and Anxiety*. 2020;37(2):134–145. [^fda-neurostar]: U.S. Food and Drug Administration. 510(k) Premarket Notification K061053, NeuroStar TMS Therapy System (Neuronetics, Inc.), cleared 2008 for treatment of major depressive disorder in adult patients who have failed to achieve satisfactory improvement from prior antidepressant medication. [^cms-lcd-tms]: Centers for Medicare & Medicaid Services. Local Coverage Determinations (LCDs) for Transcranial Magnetic Stimulation. CMS Medicare Coverage Database. (Coverage governed by MAC LCDs; no National Coverage Determination exists for TMS.) [^apa-mdd]: American Psychiatric Association. *Practice Guideline for the Treatment of Patients with Major Depressive Disorder*. 3rd ed. American Psychiatric Publishing; 2010 (and subsequent guideline updates). [^star-d]: Rush AJ, Trivedi MH, Wisniewski SR, et al. Acute and longer-term outcomes in depressed outpatients requiring one or several treatment steps: a STAR*D report. *American Journal of Psychiatry*. 2006;163(11):1905–1917. [^perera-2016]: Perera T, George MS, Grammer G, Janicak PG, Pascual-Leone A, Wirecki TS. The Clinical TMS Society consensus review and treatment recommendations for TMS therapy for major depressive disorder. *Brain Stimulation*. 2016;9(3):336–346. [^lerner-2019]: Lerner AJ, Wassermann EM, Tamir DI. Seizures from transcranial magnetic stimulation 2012–2016: results of a survey of active laboratories and clinics. *Clinical Neurophysiology*. 2019;130(8):1409–1416. [^rossi-2021]: Rossi S, Antal A, Bestmann S, et al. Safety and recommendations for TMS use in healthy subjects and patient populations, with updates on training, ethical and regulatory issues: Expert Guidelines. *Clinical Neurophysiology*. 2021;132(1):269–306. [^xia-2008]: Xia G, Gajwani P, Muzina DJ, et al. Treatment-emergent mania in unipolar and bipolar depression: focus on repetitive transcranial magnetic stimulation. *International Journal of Neuropsychopharmacology*. 2008;11(1):119–130.