An Update on Repetitive Transcranial Magnetic Stimulation for the Treatment of Co-morbid Pain and Depressive Symptoms

Review recent meta-analyses and clinical trials investigating the therapeutic use of repetitive transcranial magnetic stimulation (rTMS) for concurrent pain and depressive symptoms. Recent meta-analyses have included both pain and depression outcomes in fibromyalgia and chronic pain. Randomized controlled trials have also been conducted in post-herpetic neuralgia, trauma-related headache, and neuropathic pain with attention to both pain and depressive symptoms. In general, studies have demonstrated reduction in pain in patients with fibromyalgia as an add-on treatment, post-herpetic neuralgia, trauma-related headache, and neuropathic pain. There are variable findings for reduction in depressive symptoms in patients with co-morbid pain disorders. Theta burst stimulation (TBS) is a novel rTMS protocol that has recently been investigated in patients with depression and some smaller trials in patients with co-morbid pain disorders. These emerging treatment options may have similar or greater therapeutic potency and may be delivered with greater efficiency. There is evidence to support the use of rTMS for its analgesic effects in various pain syndromes. The variable results between trials for treatment of concurrent depressive symptoms may be due to heterogeneity in treatment protocols including parameters such as site of stimulation (primary motor cortex versus dorsolateral prefrontal cortex) and restrictions in the patient population which usually exclude primary psychiatric diagnoses. Future trials should work to standardize these protocols, investigate novel protocols like TBS, and continue to include standardized assessment of concurrent psychiatric outcomes such as depression and anxiety.