Subject:
Depression

Short Description:
Study Looks at Use of TMS to Treat Depression

Background:

Transcranial magnetic stimulation, or TMS, was approved by the FDA for treatment of major depression in October 2008. A newly published observational study evaluating the effectiveness of TMS treatment in more than 300 patients at 42 clinical settings across the United States has found that most patients responded well to this intervention, with few adverse effects (Carpenter LL et al, Dep Anx 2012;29(8):587–596).

The study followed 307 outpatients who were approved for TMS treatment due to failing at least one antidepressant trial (multiple failures were not required). Most treatment settings (76%) were private clinical practices, and TMS was paid for either by patients themselves or by their insurance provider. Importantly, both subjects and investigators received a “modest remuneration” for their participation in the study. Also, there was no control or “sham TMS” group.

The primary outcome measure was the Clinical Global Impressions-Severity of Illness (CGI-S) scale. This scale simply asks the question “how mentally ill is the patient at this time,” measured by the clinician on a scale of 0 to 7. In the study, mean CGI-S scores decreased from 5.1 at the start of treatment to 3.2 at the end of treatment (ie, the point at which the clinician felt “maximum improvement” was reached). Response rate was 58.0% while remission rate was 37.1%. Similar results were found on two secondary outcome measures, the patient self-rating scales PHQ-9 and IDS.

Given the generally positive results, investigators searched for patient-specific factors that might predict a beneficial response to TMS. They found that patients younger than 55 years of age and who had less severe depression were more likely to benefit from treatment than others. Furthermore, those who had failed only one antidepressant (54% of the sample) did better than those who had failed two or more.

TCPR's Take:
At first glance, this naturalistic study seems to show an impressive benefit of TMS in real-world settings. Side effects were minimal (there was one seizure, in a woman taking several concurrent medications who was “sleep-deprived” at the time of TMS) even with an average of 28.3 TMS sessions over 42 days. However, the take-home message is called into question by the absence of a control group, the financial incentive to both patients and providers, and the sponsorship of the paper by the TMS device manufacturer. Most important, given the increasing emphasis on placebo response and patient expectations, it would have been interesting to determine whether patients’ (or providers’) beliefs about TMS influenced response to treatment, but this was not assessed.