Treating depression could change significantly following the results of a small Canadian clinical trial that ended in 2005. The procedure used in the study freed several patients from heavy depression that had resisted medication, talk therapy and even electroconvulsive (shock) treatment. Study co-author Helen S. Mayberg cautions that any trial so small – just six patients – must be considered provisional. Yet four of the six subjects felt dramatic and lasting effects. University of Toronto neurosurgeon Andres Lozano implanted battery-powered, pacemakerlike devices underneath a patient’s clavicle, then ran flexible, hair-thin electrodes to the subgenual cingulate, a well-buried cortical area that Mayberg had previously found active in depressive or sad states. The electrodes delivered pulses of four volts, 130 times a second. Mayberg hypothesized that in badly depressed patients the subgenual cingulate acts like a switch left open, allowing depressive circuits to fire more than is necessary. Her results suggest that the regular stimulation might moderate that activity. In 2005, after a year of living with the continuous impulses, the four patients had lowered their scores on the Hamilton Depression Rating Scale from the soul-deadening high 20s to between one and eight – quite healthy.