Response Rates of rTMS Treatment for Depression at Tranquil TMS - a UK-based Clinic

The treatment of depression has continued to evolve over the years. Despite newer antidepressant medications, the STAR-D trial has clearly shown the limitations of psychopharmacology in the treatment of depression [1]. In recent times, neuromodulation has provided a ray of hope for that section of the population whose symptoms fail to respond to traditional measures. 

One of these neuromodulation treatments, repetitive Transcranial Magnetic Stimulation (rTMS) has been shown to be an effective treatment for depression. In the UK, rTMS has been approved for the treatment of depression by the NICE in 2015 and the Royal College of Psychiatrists in 2017. In the USA, the FDA has approved this treatment for treatment-resistant depression in 2008 [2]. Health Canada has approved this treatment for the treatment-resistant depression in 2002 [3]. 

NICE Guidance IPG542 (December 2015) states. The 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 for depression may be used with normal arrangements for clinical governance and audit [4]. Studies have shown that repetitive Transcranial Magnetic Stimulation (rTMS) has a definite antidepressant effect on major depression [5]. The evidence suggests that rTMS used solely or in combination with antidepressants for first-episode major depressive disorder may be more effective than antidepressants alone. Thus, the use of rTMS may shorten the treatment odyssey for patients with MDD [6].

Aim 

The aim of this study is to evaluate the success rates of the rTMS in the treatment of depression in private North West UK-based clinic. 

The general consensus is that 1in 3 patients achieve complete remission by the end of 1 year and that 1in 2 patients will show a 50% reduction in their symptoms with the rTMS [7]. 

We expect patients to halve their scores on two different rating scales -Hamilton Depression Rating Scale (HDRS) and Hamilton Anxiety Rating Scale (HAM-A) by the end of their treatment course (which could last 4-6 weeks) in order to consider it a response to treatment. 

For HDRS scores, any score of 7 or under is regarded as remission. The HAM-A scores of 10 or under were regarded as remission for the purpose of this study.

Methods 

We analysed data of all the patients who received rTMS treatment in Tranquil TMS from 1^st Feb 2018 to 31^st Dec 2019. We used 2 rating scales, Hamilton Depression Rating Scale (HDRS) and Hamilton Anxiety Rating Scale (HAM-A). 

All patients undertook HDRS and HAM-A assessments at the beginning of the treatment and this was then repeated at the start of every week of their treatment subsequently. For the purposes of this study, we decided to only include the scores from the start of the treatment and following the completion of the treatment. 

Results 

During the study period, 33 patients commenced rTMS treatment. Out of this number, 6 patients dropped out by the end of the 1st week (18.18%). The reasons for dropouts were varied-2 people thought clinic was geographically too far to commute, 3 patients changed their mind within the first few days regarding the treatment and 1 had a family incident - but none of the dropouts were due to side effect issues. 

Our sample included 27 patients all of whom were on at least 1 antidepressant medication and showing no significant response to it. Only 4 patients were drug naive. 27 patients out of 33 (81.81%) completed the treatment see (Table 1) Out of those, 9 patients received intermittent theta bursts protocol (50 Hz) for depression whilst 18 patients received standard protocol for depression (10Hz).

Table 1: below highlights the change in HDRS scores from initial to final rating scores. 

Patients received 20-40 treatments of high frequency rTMS on the Left Dorsolateral Pre-frontal cortex and a minimum of 10 treatments of low frequency rTMS (1 Hz) on the right dorsolateral prefrontal cortex. Out of the 27, 2 patients (7.4%) are currently receiving maintenance treatment every few weeks 

HDRS scores showed 12 out of the 27 patients achieved full remission at the end of the treatment (37.03%).Out of 27 patients 18 had achieved more than a 50% drop in HDRS score (66.66%). 

On HAM-A scale see (Figure 1-3) below 12 out of the 27 patients achieved full remission with scores of 10 or under (37.03%). 17 out of 27 patients had achieved more than 50% drop in HAM-A score (62.96%).

 Figure 1: HDRS - Initial to final scores.

Figure 2: HAM-A - Initial to final scores. 

Figure 3: Remission and response rates.

The study showed that our remission rate for rTMS was high (37.03%). This is comparable to the study done by Connolly et al, 2012 which showed the HDRS remission rate of 35.3% [8]. 

Our response rate (66.66%) was higher than the response rate of 41.2% quoted in the study by Connolly et al, 2012 [8]. Our rates were also higher than the metanalysis done by Berlim et al in 2014. Berlim et al carried-out analysis of the data from 29 RCTs covering 1371 patients. They found that 29.3% of patients responded to treatment and 18.6% of patients could achieve remission with high frequency rTMS [9]. 

We did not have any patients discontinuing the treatment because of the side effects of rTMS. Though our dropout rates were higher than other studies, they were not related to rTMS treatment as such.  Once again, this study shows that rTMS is an effective treatment for depression including treatment resistant depression. HAM-A scores highlights the success of anxiety protocol in helping patients with co-existing anxiety symptoms. There is a dearth in the literature regarding rTMS experience in the UK. We recommend further studies with larger sample sizemainly targeting the UK’s population.

Nikhila Deshpande and Babu Nayar are the directors of Tranquil TMS.