Repetitive transcranial magnetic stimulation (rTMS) is a first-line treatment for treatment-resistant depression (TRD) based on the Canadian Network for Mood and Anxiety (CANMAT) Guidelines.
rTMS uses magnetic pulses to stimulate neuronal pathways in the brain that are altered in mental illness. Although the exact mechanisms of its therapeutic effects is not fully understood, repeated activation of neuronal networks can alter their activity and re-establish balance between circuits. It is also believed to increased the production of brain derived neurotropic factor (BDNF) which helps in the process of neurogenesis and neuroplasticity.
Treatment indications and contraindications:
Indications
- Major Depressive Disorder (MDD): rTMS is most frequently used to treat MDD, particularly in patients who have not responded to antidepressant medications or psychotherapy. It is thought to work by stimulating areas in the brain that have reduced activity in depression, such as the dorsolateral prefrontal cortex (DLPFC). Stimulation of these areas can enhance mood and cognitive function.
- Treatment-Resistant Depression: For individuals who have not benefited from conventional treatments, rTMS offers a viable alternative. The stimulation may help ‘reset’ certain brain circuits implicated in depression, thereby improving symptoms.
- Obsessive-Compulsive Disorder (OCD): rTMS may be beneficial for OCD by targeting and modulating the activity of brain circuits involved in the disorder, such as those connecting the orbitofrontal cortex and the striatum. This can help in reducing the intensity of obsessive thoughts and compulsive behaviors.
- Generalized Anxiety Disorder (GAD): Some studies suggest rTMS can help in managing symptoms of anxiety. The treatment may reduce excessive activity in areas of the brain linked with anxiety, thereby leading to an overall reduction in anxiety levels.
- Post-Traumatic Stress Disorder (PTSD): rTMS may benefit individuals with PTSD by influencing brain regions that are over- or under-active in PTSD, such as the amygdala and the prefrontal cortex. This can help in reducing symptoms like flashbacks, hypervigilance, and emotional numbness.
Contraindications:
People with non-removable metallic, ferromagnetic objects which is less than 30 cm from the treatment coil might not be suitable for TMS and should consult with their TMS prescriber if they have any of these items. TMS can still be given to people with certain types of stents and implants. People with implanted electronic devices, like cardiac defibrillators, cochlear implants, Intracranial tumors or lesions, or nerve stimulators cannot have TMS. Dental work including standard amalgam fillings/implants and piercings are not a contraindication for TMS.
Precautionary Considerations:
- History of seizure activity, epilepsy
- Psychotic features associated with depression
- Active concurrent substance use such as narcotic or alcohol addiction
- Those who are unable to comply with treatment requirements such as patients with delirium/dementia or physical inability to hold still for the entire treatment session
- Poor response or significant adverse reaction to previous rTMS or other neuromodulation technique
rTMS treatment is not covered by Alberta Health Insurance (AHI) at this time and is therefore a private pay treatment. Dr. Comeau is a registered provider with Veteran’s Affairs (VA). Some disability and insurance companies may provide coverage, we recommend that you enquire with your provider to see if you are eligible for funding.
