Electronic Letters to:

REVIEW ARTICLES:
JOSÉ LUIS R. MARTIN, MANUEL J. BARBANOJ, THOMAS E. SCHLAEPFER, ELINOR THOMPSON, VÍCTOR PÉREZ, and JAIME KULISEVSKY
Repetitive transcranial magnetic stimulation for the treatment of depression: Systematic review and meta-analysis
The British Journal of Psychiatry 2003; 182: 480-491 [Abstract] [Full text] [PDF]
*eLetters: Submit a response to this article

Electronic letters published:

[Read eLetter] Is it a 'sham'?
M E Jan Wise   (12 July 2003)

Is it a 'sham'? 12 July 2003
Top
M E Jan Wise,
Psychiatrist
RCPsych

Send letter to journal:
Re: Is it a 'sham'?

jan.wise{at}cnwl.nhs.uk M E Jan Wise

Editor BJP 17 Belgrave Squ London SW1X 8PG

11th June 2003

Dear Editor,

Martin et al reviewed repetitive transcranial magnetic stimulation (rTMS) as a treatment of depression (1). They make many valid points about rTMS, not least of which may be the difficulty of providing sham treatment. Recently manufacturers have included shielding within the field projector allowing for adequate blinding of the patient and assessor. In all other respects the ‘sham’ treatment is identical as the temperature rise in the device as well as the noise generated remain consistent (2).

They have failed to consider in their analysis that for most of the equivocal studies the ‘sham’ treatment involved holding the field generator at a 45-degree angle to the head. Thus not only can the therapist but also the patient tell that treatment is different. Of even greater concern than this difficulty is that a 45-degree angle still projects a magnetic field through the cortex. Shielding the field projector ensures that the sham treatment has no magnetic influence on the cortex.

A point that the authors attempted to explore is the complexity of the treatment. Whilst there are problems with correctly placing the magnetic field over the prefrontal cortex (L Grunhaus, personal communication), there are further issues over the correct intensity, duration, intertrain frequency and frequency of the stimulus. This is analogous to wondering with ECT what dose, how many times per week, at what frequency should the alternating current be, and how many times in each session should the current be applied.

With the increased hostility to ECT(3) it is important that whilst all these questions are investigated, a potential alternative is not prematurely discounted.

Yours sincerely

Dr M E Jan Wise Adult Psychiatry, St Charles Hospital Exmoor Str, London W10 6 DZ

1 Marin J.L., Manuel J.B., Schlaepfer T.E et al, Repetitive transcranial stimulation for the treatment of depression. BJP,182,480- 491.

2 Magstim Placebo Coil System operating Manual. The Magstim Company Ltd, Wales , UK 1999.

3 White C. New Guidance on ECT looks set to curb its use. BMJ, 326, 1003. 10 May 2003.

Conflict of interest: None