Patients with depression that doesn’t respond fully to drug therapy may gain some relief with multiple courses of repetitive transcranial magnetic stimulation (rTMS), a non-invasive treatment that alters the electrical activity of the brain through the use of magnetic fields, Boston-based researchers have shown.

Dr. Alvaro Pascual-Leone at Beth Israel Deaconess Medical Center and colleagues studied the benefits of repeated courses of rTMS in 16 patients with depression that did not respond to conventional therapy, but did respond to a 10-day course of rTMS.

Patients were followed for 4 years, during which time they had a total of 64 repeat bouts of depression. The severity of depression was assessed before and after each rTMS treatment session using a standard questionnaire called the Hamilton Rating Scale for Depression (HAM-D).

A treatment response was defined as a 50 percent or greater reduction in the HAM-D score, the report indicates.

Approximately one-half of the patients responded to repeat courses of rTMS, Pascual-Leone and colleagues report in the Journal of Clinical Psychiatry. The average drop in the HAM-D score was 64.8 percent.

On average, rTMS sessions took place 5 months apart. The rTMS-treated patients were able to go for up to 43 months without requiring antidepressant medications.

The procedure was well-tolerated and no safety concerns arose during the study, the report indicates.

SOURCE: Journal of Clinical Psychiatry, June 2008.