Transcranial magnetic stimulation (TMS) was approved by the FDA to treat some patients with depression in 2008, and has since been used in treatment plans for a variety of other health issues. But the increased use of TMS raises a number of ethical considerations. For example, are health care providers doing enough to track adverse side effects? And are patients able to make informed decisions about whether to receive TMS treatment?
A new book addresses these and related questions, capturing both the broad field of research that has already been done on TMS and outlining a path forward for using TMS ethically. The book, "TMS and Neuroethics," was edited by Veljko Dubljević - the Joseph D. Moore Distinguished Professor of Philosophy and Science, Technology & Society at NC State - and Jonathan Young, medical assistant professor in the Department of Psychiatry & Behavioral Sciences at Duke University and staff psychatrist at Durham VA Health Care System. To learn more about the issue we talked with Dubljević and Young.
The Abstract: What is transcranial magnetic stimulation (TMS)? How common is it, and what is it used for?
Veljko Dubljević: Transcranial magnetic stimulation is one of several noninvasive brain stimulation modalities, which (in modern form) was originally developed in 1985 and initially approved by FDA as a treatment for medication-resistant major depressive disorder (MDD) in 2008. Using electromagnets similar in strength to a magnetic resonance imaging (MRI) scan, the magnetic fields of TMS pass through the skin and skull unimpeded, directly reaching and stimulating the brain. Alongside neuroimaging, TMS has allowed neuroscientists to directly study the brain without invasive procedures and elucidate neuroanatomical functions since the 1990s. Through repeated stimulation (repetitive TMS) and a course of treatment, abnormal brain activity and patterns can be normalized, resulting in therapeutic benefit.
Since original approval for clinical use, the psychiatric indications for TMS have expanded to include obsessive compulsive disorder (OCD) and tobacco smoking cessation, but TMS is also approved as a migraine treatment and for pre-neurosurgical mapping. Currently, there are thousands of clinics across the country offering TMS, and it has become a mainstay of depression treatment.
TA: The book is titled "TMS and Neuroethics." What are the ethical questions surrounding TMS?
Dubljević: TMS presents several ethical challenges, primarily centered on the complexities of informed consent, and the concerning lack of standardized side-effect reporting. Minor side effects, such as transient headaches, scalp discomfort, and lightheadedness, are relatively common and generally well-tolerated. However, more serious adverse events, including the rare but significant risk of seizures, raise a more profound ethical concern.
A key issue is the underreporting of these side effects, which can be due to a lack of a centralized registry, inadequate patient follow-up, or a potential disincentive for clinics to report negative outcomes. This creates a significant gap in our understanding of the true safety profile of TMS and compromises the ability of both clinicians and patients to make fully informed decisions.
The potential for off-label use of TMS for a wide range of unproven conditions further complicates matters, as the risk-benefit analysis for such applications is not well-established, raising additional patient safety concerns and ethical obligations for practitioners.
TA: Your book looks at the existing work that's been done on the ethics of TMS, as well as what the path forward might look like. Let's focus on the existing work first. What sort of research has been done to evaluate the ethics of TMS technologies and practices?
Jonathan Young: The majority of human research on TMS has been done in patient populations, which include efficacy and safety/side effects. Studies on the ethics of TMS include both clinical and non-clinical applications, and have considered a variety of impacts for both patients and family members. These findings are summarized in the second part of the volume and cover a range of issues, such as lack of response to TMS treatments, complexities in vulnerable populations (e.g., the elderly, people with suicidal ideation, etc.), and promising results in trials on substance use disorders beyond smoking.
TA: Your book also looks to the future, providing guidance on issues related to both justification for the use of TMS and an informed consent process for patients receiving TMS. Two questions here. First, who is this guidance for? And second, what are the key things you want those people to consider?
Young: Guidance on the use of TMS through an informed consent process is primarily for clinicians and human researchers. Key considerations for patients being considered for TMS include the potential benefits (e.g., therapeutic effects), potential risks (e.g., headaches, seizures), and alternatives (e.g., medications, psychotherapy, etc.). These factors, along with scientific rationale, influence clinical research using TMS through a regulatory approval process in which an Institutional Review Board (IRB) considers the safety of human participants in the context of a trial.
TA: Last question: why write this book now?
Dubljević: Discussing the ethical issues surrounding TMS is important now because of its increasing clinical acceptance and the expansion of its use beyond its original, FDA-approved applications. As TMS becomes more widespread, moving from specialized clinics to general psychiatric and neurological practices, the potential for its off-label use grows significantly.
Clinicians are exploring its efficacy for a range of conditions for which it isn't yet officially approved, such as chronic pain, addiction and even cognitive enhancement. This raises complex ethical questions about patient safety, especially when there's a lack of robust data on the long-term effects for these new uses. It also brings to light issues of access and fairness, as not everyone has the required financial resources or the time to benefit from TMS. Addressing these issues now is crucial to establishing clear guidelines and ethical frameworks to ensure that TMS is used responsibly, prioritizing patient well-being over commercial interests.
