Transcranial magnetic stimulation (TMS) for depression
- NICE states that "..evidence on repetitive transcranial magnetic stimulation for depression shows no major safety concerns. The evidence on its efficacy in the short-term is adequate, although the clinical response is variable..."
- repetitive transcranial magnetic stimulation (rTMS) does not need anaesthesia and can be done on an outpatient basis. A purpose-made electromagnetic coil is held against the scalp with the intention of inducing electric currents in the cerebral cortex. Imaging may be used to help target specific areas of the brain. Treatment is usually considered for patients with depression that has not responded to antidepressant medication or patients for whom antidepressants are not suitable
- in rTMS, repetitive pulses of electromagnetic energy are delivered at various frequencies or stimulus intensities. Conventional rTMS is a repetition of individual pulses at a pre-set interval (train of pulses), whereas theta-burst rTMS is a repetition of short bursts of pulses at a pre-set interval (train of bursts). Stimulation can either be delivered unilaterally, over the left or right dorsolateral prefrontal cortex, or bilaterally over both cortices. Bilateral stimulation may be done sequentially or simultaneously
- treatment with rTMS usually comprises daily sessions lasting about 30 minutes, typically for 2 to 6 weeks
Transcranial magnetic stimulation (TMS) has been successful in treating patients with treatment resistant depression (TRD) (2):
- response rates to TMS range between 50% and 55%, and the remission rates range between 30% and 35% in patients with major depression
- the dorsolateral prefrontal cortex (DLPFC) is the part of the brain that has been reported dysregulated in patients with major depression, resulting in symptoms consistent with this condition depression
Transcranial direct current stimulation (tDCS) for depression
- is a method of brain stimulation involving passing a weak current (1-2mA) across the cortex using at least two electrodes (3)
- evidence has shown that transcranial direct current stimulation (tDCS) slowed cognitive decline in older adults with remitted major depressive disorder (rMDD) or mild cognitive impairment (MCI) (4):
- patients randomized to receive active CR plus active tDCS experienced a slower cognitive decline over a median follow-up of 4 years than those randomized to receive sham-plus-sham treatments
- effects were more prominent in the rMDD (with or without MCI) than in the MCI without rMDD group
- the study authors concluded that:
- treatment of CR plus tDCS is effective in slowing cognitive decline in older adults with rMDD.
Reference:
- NICE (December 2015). Repetitive transcranial magnetic stimulation for depression
- Rizvi S, Khan AM. Use of Transcranial Magnetic Stimulation for Depression. Cureus. 2019 May 23;11(5):e4736.
- Chase HW et al. Transcranial direct current stimulation: a roadmap for research, from mechanism of action to clinical implementation. Mol Psychiatry. 2020 Feb;25(2):397-407.
- Rajji TK, Bowie CR, Herrmann N, et al. Slowing Cognitive Decline in Major Depressive Disorder and Mild Cognitive Impairment: A Randomized Clinical Trial. JAMA Psychiatry. Published online October 30, 2024.