The most common question that people ask when they start TMS is how long it will take to get well with TMS. A recent article published in the American Journal of Psychiatry looked at the results from a six week study designed to compare theta burst and regular TMS in order to assess patterns of response over time.
The authors identified four different trajectories of response. Of the 388 patients in the study, 73 patients (only 19%!) fell into the nonresponse category. This is good news for those considering TMS for treatment refractory depression.
About 40% of the patients had low baseline symptoms and had a linear response to TMS.
30% of the patients had higher baseline symptoms and a linear response.
Roughly 19% of patients had a rapid response, with an almost 50% reduction in symptoms in the first week.
Interestingly, there was no difference in response patterns between theta burst and regular TMS.
The study lasted only six weeks, so it doesn’t answer the question of what the differences in long term outcomes between these patient groups.
Take a look at the graph and you will see that there was no slowing down of response over the six weeks of treatment. This fits with the overall clinical literature which suggests that more and more people respond the longer the treatment lasts with no clear endpoint. In other words more people respond with six week trial than with an eight week trial, and more people respond with an eight week trial than a six week trial, and the few studies that have gone further than eight weeks also’s show larger response rates.
Trajectories of Response to Dorsolateral Prefrontal rTMS in Major Depression: A THREE-D Study. Tyler S. Kaster, Jonathan Downar, Fidel Vila-Rodriguez, Kevin E. Thorpe, Kfir Feffer, Yoshihiro Noda, Peter Giacobbe, Yuliya Knyahnytska, Sidney H. Kennedy, Raymond W. Lam, Zafiris J. Daskalakis, and Daniel M. Blumberger. American Journal of Psychiatry 2019 176:5, 367-375