Despite the fact that there is no conclusive information about how long it takes for Transcranial Magnetic Stimulation (TMS) to be effective, the studies conducted give us an idea.’ Although the time needed to take benefit from the treatment varies based on the method of treatment, the course of the disorder, and the person.
A development increasing from 26% to 42% was shown in the depression scale measured via repetitive TMS (rTMS) implemented for two weeks on only right prefrontal cortex, or on both right and left prefrontal cortices at low frequency (1 Hz) in 5 different studies carried out on depression patients.
In the majority of the studies carried out with TMS, the antidepressant treatment continues for 2 weeks. This span is longer for drugs (6-8 weeks). A few studies focusing on the effects of rTMS at the end of the 4-week implementation showed that a development was observed in weeks 3 and 4.
rTMS is implemented on each day of the week in many studies. Nevertheless, there is too little information about what the proper frequency is. In practice, this span could vary between multiple sessions during the day to 2-3 sessions within a week.
The studies regarding the effectiveness of rTMS show that the symptoms may reoccur 4-6 months following the cessation of the treatment.
The critical assessment point is 3 weeks in the trials, and the patient must have an improvement by at least 30% in the depression scale, or an active treatment must be started. Taking generally 3 weeks, the minimum recovery duration may be longer in some patients. In case there are no changes in the mood symptoms in 4 weeks, it is assumed that there is no clinical reaction to TMS. If there are positive changes in the patient, and if these changes continue after 12 weeks, then it could be said that the TMS treatment is useful.
A retrospective research was made in 307 patients receiving TMS implementation for depression treatment at 42 clinics in America. The clinical symptoms of the patients were measured by the clinician at the beginning of the treatment, in week 2 where the maximum benefit is taken from the treatment, and in week 6. The patients received 28 sessions of TMS treatment in average, the treatment lasted for 42 days in average, and the left prefrontal cortices were stimulated in nearly all patients. According to the results, 58% of the patients reacted to the treatment, while 37% had complete recovery. It was seen that the treatment yielded better results in patients, who were affected less by the depression-based symptoms prior to the treatment, and in those of younger ages.
In the studies carried out with the elders with depression, it is shown that the antidepressant effects of rTMS decrease in the case that there is atrophy in prefrontal area. Therefore, there are some opinions concerning the fact that rTMS is less effective in the depression observed in the elders.
As the studies carried out on TMS continue and the use in clinical application increases, it will be possible to obtain more accurate information about how long it takes to benefit from it.