Theta burst stimulation, often shortened to TBS or iTBS, is a newer pattern of TMS pulses modeled on the brain's own rhythms. Instead of steady trains at 10 pulses per second, theta burst delivers short bursts of three very fast pulses, repeated five times per second, which is the theta frequency seen in the hippocampus during learning. The intermittent form, iTBS, delivers these bursts in on and off cycles and is thought to strengthen connections in the stimulated region. The whole session takes about three minutes rather than the 20 to 40 minutes of a conventional protocol.
The FDA cleared iTBS for major depressive disorder in 2018 after a large Canadian trial, published in The Lancet, found it was not inferior to standard high-frequency rTMS. The shorter session makes treatment easier to fit around work and family, and it allows clinics to offer accelerated schedules with several sessions in a single day. Research on accelerated protocols is still maturing, and insurance coverage usually follows the standard once-daily course. Side effects are similar to other forms of TMS: scalp discomfort and mild headache early on. Whether you receive theta burst or a conventional protocol depends on the device, the condition, and your psychiatrist's judgment. Ask about the protocol planned for you during your TMS consultation at Stedfast Psychiatry.