Transcranial Magnetic Stimulation in Clinical Psychiatry. Edited by Mark S. George & Robert H. Belmaker. American Psychiatric Publishing. 2007. 289 pp. US$55.00 (pb). ISBN 9781585621972

Confirming the built-in sad obsolescence of books, the editors predict:

‘At the time of writing, one TMS company has completed a large multisite (sic!) clinical trial of TMS in depression and has submitted the results to the U.S. Food and Drug Administration (FDA) for potential approval of treatment. Thus, it is likely that clinicians soon will have a new treatment tool, unlike virtually anything they are familiar with’

Shoot and darn: in preparation of the FDA approval procedure, an expert panel

‘… was generally unimpressed with the company's data, which showed a slight statistical advantage in depression symptoms over dummy therapy after six weeks of treatment. Several panelists expressed dismay that patients showed no improvement on some depression scales and only minor improvement on ones that showed a difference. ‘The panel seems to be in consensus that the primary analysis did not establish efficacy,’ said Thomas Brott, the committee's chairman. ‘Perhaps a reasonable person could question whether there has been an effect at all,’ said Brott, a neurologist from Mayo Medical School in Jacksonville, Fla….Ann Costello, an FDA medical reviewer, questioned whether the mixed evidence of effectiveness in Neuronetics’ studies contained “any clinically relevant information.”’ (Zwillich, 2007).

To put it mildly, the jury is still out on the issue of whether transcranial magnetic stimulation (TMS) is clinically useful in depression. Large meta-analyses, although they may show an overall effect of TMS over placebo, also reveal a large heterogeneity of results and little in terms of outcome predictors, be it among patient or treatment variables. This:

‘… can be interpreted in 2 ways: either study sizes and numbers and designs are insufficient to afford the power necessary… or TMS has a nonspecific (i.e. placebo) effect on depression that is not influenced by study parameters.’ (Herrmann & Ebmeier, 2006).

The uncomfortable feeling remains that without a strong industrial interest it will be difficult to assemble the evidence necessary for statutory licensing. The large spontaneous recovery rate, significant placebo effects and sensitivity to sample selection in studies of clinical depression require large participant numbers, a condition that is difficult to fulfill by the academic cottage industries that have mainly been involved with trials of TMS.

Fortunately, TMS has other, more scientific, attractions and these are well reviewed in the ten chapters of this generally balanced and readable summary of the field. The authors are well informed, as one would expect from the main research proponents of the method. Both the budding magneto-therapist and the neuroscientist will find technical and scientific details that are essential for their work. The layout is clear and concepts, as well as techniques, are generously and well illustrated. The price is moderate and seeing that the field changes so quickly, the book will be a ‘best buy’ at least for the next 6 months.