Effects of left frontal transcranial magnetic stimulation on depressed mood, cognition, and corticomotor threshold

Biol Psychiatry. 1999 Jun 1;45(11):1440-6. doi: 10.1016/s0006-3223(99)00031-1.


Background: The pathophysiology of depression may include synaptic hypoactivity of left prefrontal cortex. Several groups of investigators have described improved mood associated with rapid transcranial magnetic stimulation (rTMS) but have not looked for possible cognitive side effects associated with left prefrontal magnetic stimulation.

Methods: We measured the effects of left prefrontal rTMS on mood, cognition, and motor evoked potential threshold in 10 patients with medication-resistant major depression.

Results: In a 2-week open trial of left prefrontal rTMS off antidepressant medications, scores on the Hamilton Rating Scale for Depression and the Beck Depression Inventory decreased by 41% and 40%, respectively. After resuming pre-rTMS antidepressant medication, improvement in mood was still significant at 1 and 3 months later. rTMS had no adverse effects on neuropsychological performance. rTMS treatments were associated with significant decreases in motor evoked potential threshold in the 9 of 10 patients who remained off psychotropic medications during the 2-week treatment period.

Conclusions: These preliminary data suggest that left prefrontal rTMS is safe and improves mood in patients with medication-resistant major depression. Changes in motor evoked potential threshold suggest that prefrontal rTMS may alter brain activity at sites remote from the stimulation. Double-blind, sham-controlled studies are needed.

Publication types

  • Case Reports
  • Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Cognition / radiation effects*
  • Depressive Disorder / physiopathology
  • Depressive Disorder / therapy*
  • Differential Threshold / radiation effects
  • Electromagnetic Fields* / adverse effects
  • Evoked Potentials, Motor / radiation effects*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Motor Cortex / physiology
  • Neuropsychological Tests
  • Physical Stimulation
  • Prefrontal Cortex / radiation effects*
  • Statistics, Nonparametric
  • Treatment Outcome