In transcranial magnetic stimulation ('TMS'), a magnetic coil is placed next to the scalp. The coil delivers magnetic pulses. These cause electrical changes in the brain and stimulate brain cells.
Treatment is usually repeated a number of times and is known as repetitive TMS (rTMS).
In the most commonly used form of rTMS, the coil is placed over the left front area of the brain. This type of rTMS uses fast pulses. It is called High Frequency rTMS.
Low Frequency rTMS uses slower pulses. In this form, the coil is placed over the right front area of the brain or over both sides of the brain.
rTMS changes brain activity. It is not known exactly how this affects depression.
High frequency rTMS increases activity in parts of the brain that may be under active. Low frequency rTMS decreases activity in parts of the brain that may be overactive.
rTMS may balance the activity levels in different parts of the brain. It can also change blood flow and brain chemicals.
Some studies have compared rTMS with sham rTMS. In the sham form of rTMS, a fake coil is placed over the scalp. Alternatively, a real coil is used but is pointed away from the scalp.
This form of rTMS has been studied the most often. These studies have found that it is more effective than sham rTMS. It can also be effective for some people who have not been helped by medication or psychological therapies.
Other studies have compared high frequency rTMS to ECT (Electro Convulsive Therapy). In these studies, ECT was more effective.
Some studies have compared low frequency rTMS with sham rTMS. These studies have suggested that low frequency rTMS may also be effective.
More research is needed on rTMS. Studies so far have often involved small groups of people. Doctors are still working out the best ways to use rTMS. This means the treatments used in different studies have not been exactly the same. For example, the number of treatments has not been the same over different studies.
It is not yet clear whether successful rTMS treatments produce improvements that last over time.
TMS has mainly been studied in adults. There is a small amount of evidence to suggest that it is also effective in older adults. However, research on older people has found smaller effects. There is little evidence about TMS use in children and adolescents.
The most commonly reported disadvantage of rTMS is that it can cause discomfort on the scalp or a headache.
The most serious disadvantage of rTMS is that it can cause seizures. This occurs rarely. Doctors now use rTMS under special guidelines designed to reduce the risk of seizures and other problems.
TMS is still an experimental treatment. It is available in many parts of Australia although it can be hard to get. It is available through some state public health systems. It is available in research trials and some clinics and hospitals offer TMS as a private health service.
Information about TMS in Australia is available from the Monash Alfred Psychiatry Research Centre on 03 9076 6595.
Psychological therapies and anti-depressant medication are still the first options for treatment. If these are not helpful for your depression, you might consider rTMS. Your doctor will help you work out if rTMS might be suitable for you. If you are treated with rTMS, specialist doctors will work out which type is best for your condition.
rTMS can be effective for adults and older adults. However, more research is needed before a recommendation can be made for children and adolescents.
Last reviewed and updated: 16 March 2015