In the February issue of TCPR, we reported a recent FDA panel’s opinion that rTMS (repetitive transcranial magnetic stimulation) was relatively ineffective for treatment-resistant depression. The type of rTMS that has been tested for depression generally involves 10 Hz (ten pulses per second). But when the pulse of magnetic coils is slowed down to only 1 Hz, this reduces neuronal excitability, temporarily “stunning” those neurons subjected to the magnetic field. Researchers have been using this property to try to turn off the parts of the brain responsible for auditory hallucinations in schizophrenic patients. In a recent meta-analysis of such studies, the authors reviewed 10 TMS controlled trials (with sham-TMS as the control), and reported a robust average effect size of 0.88 (Aleman A et al., J Clin Psychiatry 2007;68:416-421). In the largest of the studies they reviewed, the anti-hallucination effect lasted about five months.
TCPR’s Take: This is potentially exciting stuff, but as is always the case with research, the devil is in the details. Most of these studies use specially created auditory hallucination scales to demonstrate a benefit of rTMS. These scales yield “hallucination scores” that decrease significantly with treatment, and are great for statistical testing, but not so helpful for clinicians trying to divine the applicability of the results to their patients. In fact, this meta-analysis found that while slow rTMS appears to decrease AH, it does not improve overall ratings of positive symptoms, making it debatable how useful this expensive treatment is likely to be forour patients.
PO Box 626, Newburyport MA 01950