Transcranial Magnetic Stimulation (TMS) is a non-invasive procedure that uses magnetic fields to stimulate nerve cells in the brain. It is most commonly approved by the U.S. Food and Drug Administration (FDA) for treating major depressive disorder (MDD). The treatment involves placing an electromagnetic coil against the scalp, which delivers magnetic pulses to specific brain regions associated with mood regulation, such as the dorsolateral prefrontal cortex (DLPFC). Individuals often question TMS’s potential effects on existing symptoms, particularly the possibility of anxiety worsening, since anxiety frequently occurs alongside depression.
Is Worsening Anxiety a Known Side Effect of TMS?
Increased anxiety is generally not considered a common or lasting side effect of TMS, though a temporary increase is a documented, infrequent experience for some patients, particularly in the initial treatment phase. TMS is often effective at reducing anxiety symptoms, especially in cases of anxious depression. The likelihood of developing significant, long-term anxiety symptoms is low, as the treatment’s localized nature avoids the systemic side effects common with many oral medications.
When temporary anxiety occurs, it is often mild and transient, lasting a few days to a couple of weeks. This temporary symptom worsening is sometimes referred to as a “TMS dip,” a phase where symptoms briefly intensify as the brain adjusts to new neural activity patterns. The neurobiological mechanism involves stimulating frontal cortical regions, which can temporarily heighten alertness or nervousness. Specific stimulation protocols can influence the outcome, as some older studies reported increased anxiety using high-frequency repetitive TMS over the prefrontal cortex.
Early anxiety can also be psychological, stemming from the anticipatory stress of undergoing an unfamiliar medical procedure. The concept of brain stimulation can be intimidating, leading to uncertainty about the treatment’s effectiveness or the physical sensations it creates. For the majority of patients, however, any anxiety experienced is short-lived and resolves as the sessions continue.
Clinical Reasons Why Anxiety Levels May Increase
The temporary spikes in anxiety that patients report are often linked to the physical experience of the treatment or the specific stimulation parameters used. The magnetic pulses produce a loud clicking sound and a tapping sensation on the scalp, which can be startling and anxiety-provoking for some individuals. The close proximity of the magnetic coil to the head can also create a feeling of confinement or tension.
Clinicians proactively manage this effect through several strategies, emphasizing the transient nature of the symptoms. The treatment team may adjust the stimulation intensity, ensuring it is no higher than necessary to achieve the therapeutic effect. If the high-frequency stimulation commonly used for depression exacerbates anxiety, the clinician might change the frequency or switch to a different protocol.
Providing patients with relaxation techniques before or during the session is a common intervention to help manage nervousness. If anxiety worsens significantly or becomes intolerable, the protocol is typically paused or immediately modified to restore patient comfort. This individualized approach ensures the temporary adjustment phase is managed effectively until the patient experiences the intended long-term symptom relief.
Understanding the Full Safety Profile of TMS
While the focus is often on anxiety, the overall safety profile of TMS is excellent, with most side effects being minor and self-limiting. The most common physical side effects are temporary headaches or discomfort at the stimulation site on the scalp, which typically diminish over the course of treatment. Some patients also report lightheadedness, dizziness, or a twitching sensation in the facial muscles caused by the magnetic field stimulating nearby nerves.
The most serious, though extremely rare, risk associated with TMS is the induction of a seizure. Estimates suggest this occurs in fewer than 3 patients per 100,000 sessions, underscoring its infrequency. Rigorous screening procedures are implemented before treatment begins to reduce this risk, specifically excluding patients with a history of epilepsy or certain metal implants in the head or neck. The non-invasive nature of TMS and its localized effect on the brain make it a generally well-tolerated option compared to treatments that affect the entire body.