+ How can I describe rTMS to my patients?
rTMS is a relatively new treatment for major depression, approved by Health Canada since 2002. It is also being explored as a treatment for several other kinds of neurological and psychiatric disorders. Unlike medications or therapy, rTMS treats these disorders by stimulating the brain’s neurons directly. It does this using pulsed magnetic fields that are as strong as the one in an MRI scanner, but focused into an area the size of a toonie. The pulses are applied non-invasively through a magnetic coil held against the scalp. By applying repeated pulses of magnetic stimulation over time, rTMS can gradually increase or decrease the activity in the region of the brain underneath the magnetic coil. In major depression, and many other kinds of psychiatric and neurological illnesses, there are parts of the brain that are abnormally underactive or overactive. Over a series of treatment sessions, rTMS can correct these abnormalities to restore normal patterns of brain activity, and thereby treat the illness.
+ What medications may interfere with rTMS?
In general, GABAergic medications and anticonvulsants may block the effects of rTMS, and are ideally avoided as much as possible if a patient is to undergo rTMS.
For the majority of patients, we ask that anticonvulsant medications (including gabapentin, pregabalin, topiramate, lamotrigine, valproate, carbamazepine, and phenytoin, among others) be discontinued prior to rTMS.
We also generally require that the patients be taking benzodiazepines at less than 4 mg of lorazepam equivalent per day, prior to beginning treatment. Higher doses require more intense stimulation and may negatively impact both the tolerability and the likelihood of success.
+ What management steps should I consider during rTMS?
Patients do not need to stop or start taking medications prior to beginning treatment, but should maintain a stable regimen and consistent adherence. We routinely advise against any changes to the medication regimen for 4 weeks before and during rTMS treatment. The issue is that concurrent medication changes will confound the interpretation of response or nonresponse to rTMS. rTMS responders usually continue to respond to rTMS in future episodes, and nonresponders do not. For this reason, it is useful to have unambiguous information on whether the rTMS treatment was associated with a successful or an unsuccessful outcome.
+ How does rTMS compare to other forms of neurostimulation?
Four of the most common forms of neurostimulation for major depression form a spectrum from least invasive / least potent to most invasive / most potent. Transcranial direct current stimulation (tDCS) applies very mild electrical currents through scalp electrodes to alter brain activity. Though very well tolerated, its efficacy in depression is still to be firmly established. rTMS carries a common risk of headache and a rare risk of seizure, but has well-established efficacy against refractory depression, achieving close to 40% remission rates in some studies. Electroconvulsive therapy (ECT) uses external electrodes to induce a seizure under general anesthesia. ECT’s efficacy is greater than rTMS, with remission rates of 60-70% in refractory depression. However, tolerability is hampered by enduring stigma as well as adverse effects on episodic memory. Deep brain stimulation (DBS) is currently the most powerful of neurostimulation treatments, effective even in ECT-refractory patients, and achieving reponse in >60% and remission in >40% of such patients.
+ What kinds of disorders can be treated with rTMS?
So far, the strongest evidence base for rTMS is in the treatment of major depressive episodes. Patients with unipolar depression, bipolar depression, and postpartum depression may all benefit from the technique. Efficacy rates have been improving steadily over the last two decades, and the most recent generation of studies are achieving response (>50% reduction in symptoms) in 50-60% of patients and remission in 30-35% of patients with medically refractory depression. We are also seeing encouraging results in refractory eating disorders (particularly bulimia nervosa), impulse-control disorders, obsessive-compulsive disorder, and certain patients with neuropathic pain. However, these indications should still be considered investigational for the time being.
+ At what point should I consider referring a patient for rTMS?
+ What kind of patients are good candidates for rTMS?
Good candidates for rTMS have unipolar or bipolar depression as a primary diagnosis, have a history of episodic rather than chronic lifelong depression, have not previously failed to respond to ECT or rTMS, have had remediable life stressors (for example, divorce or legal proceedings) at least somewhat optimized prior to treatment, are sufficiently motivated and reliable to adhere to the schedule of treatments, and reside within easy commuting distance of the clinic. Ideally, a plan for psychiatric follow-up (medications, individual or group therapy) should be arranged prior to or during the course of treatment, to reduce the risk of relapse.
+ What kind of patients are poor candidates for rTMS?
Poor candidates for rTMS are those with lifelong, chronic depression or dysthymia, those with depression secondary to personality disorders or active substance abuse, those who have previously failed to respond to ECT or rTMS, those with unoptimized life stressors (for example, choosing to live with an ex-spouse, in the midst of divorce proceedings, during treatment), those with ambivalent motivation for treatment or sporadic adherence to treatment, and those residing farther than a 1 hour commute from the clinic. Patients whose primary goal is to obtain long-term psychiatric care are also not ideal referrals — the rTMS clinic provides a discrete follow-up period of 4 appointments over 6 months after treatment completion, in order to allow prompt access for new patients seeking treatment.
+ How do I refer a patient for rTMS?
Please bear in mind that patients must be on a stable regimen of medications for at least 4 weeks before they can begin treatment. Making a medication change just prior to the assessment may cause delays in starting the course of rTMS. Once assessed, suitable candidates can usually begin treatment within 1-2 weeks of assessment.
+ What management steps should I consider if rTMS is successful?
Where rTMS is successful, the effects will typically last for 6-12 months even in the absence of other interventions. However, we recommend using this period as a window of opportunity to address psychosocial stressors perpetuating the illness, to optimize medications, and to bolster core emotion-regulation and interpersonal skills through structured psychotherapy. While the best choice of psychotherapy modality depends on illness type and patient preference, certain therapies are specifically designed to address relapse into depression. Mindfulness-Based Cognitive Therapy (MBCT) is an 8-week group course devised for this purpose, and this therapy is broadly recommended to all patients who successfully complete rTMS for depression. Several MBCT programs are available in Toronto with either public or private funding. We recommend referral to one of these programs after successful rTMS, and are happy to provide copies of the initial assessment report in order to facilitate this step. Patients unable or unwilling to enrol in such a course may benefit from reading The Mindful Way Through Depression, which contains a self-guided version of the MBCT curriculum that includes the core set of guided meditations and exercises on an accompanying compact disc.
+ What management steps should I consider in rTMS nonresponders?
Nonresponse to rTMS should prompt a review of the etiology and course of the depressive symptoms. In patients with chronic illness, no sustained periods of euthymia, and significant deficits in social or emotion-regulating abilities, a course of psychotherapy may be the most effective means of building core interpersonal and emotion-regulation skills. If these skills are definitely present based on past history, or if symptoms are too severe to permit a meaningful level of engagement in therapy, three options are available. The first is to pursue an additional course of rTMS using a different target region or stimulation technique. Efficacy data on the merits of this approach are still lacking. The second is to proceed to a more potent form of brain stimulation: electroconvulsive therapy (ECT) or its magnetically-induced counterpart, magnetic seizure therapy (MST), which is now available in Canada via our colleagues at the Centre for Addiction and Mental Health. The third option is to pursue referral for advanced psychopharmacology, which is offered at UHN via the Mood Disorders Psychopharmacology Unit. The rTMS Clinic is happy to help arrange for any of these three latter options during the follow-up period.
+ What follow-up care is provided for patients who undergo rTMS?
The rTMS Clinic provides a standard schedule of 1-3 follow-up appointments over the 3 months following treatment. Additional appointments can be arranged by patient request if necessary. The aim of these appointments is to monitor for signs of early relapse, and to facilitate adherence to a regimen of medications and psychotherapy (for example, Mindfulness-Based Cognitive Therapy groups) to reduce the risk of relapse in the future. For nonresponders, the aim of the followup period is to help arrange for referral to other treatment options as above.
Due to the volume of patients seeking treatment, the Clinic unfortunately cannot assume responsibility for managing medications or providing structured psychotherapy during the treatment or follow-up period. In order to allow us to offer treatment to as many patients as possible, aspects of psychiatric care other than the rTMS itself remain the responsibility of the referring physician.
+ What should I do if a patient relapses?
Patients who have responded to rTMS in the past will typically respond again in the event of relapse. Thus, if a patient does relapse, they can be referred back to our clinic to consider a booster course of rTMS. The duration and scheduling of the booster will depend on the severity of the relapse. Relapses should also trigger a careful review of whether medications and medication adherence have been optimized, whether psychosocial stressors have been adequately addressed, and whether appropriate psychotherapies have been pursued. These aspects of care are essential to reducing the risk of relapse and the need for booster or maintenance rTMS.
+ Can I schedule a visit to observe an rTMS treatment?
We are pleased to arrange for interested physicians, whether psychiatrists or general practitioners, to visit the clinic and observe rTMS treatment. We do not currently offer training in rTMS per se. However, there are several established rTMS centres that do offer such training as a formal course.