Efficacy of transcranial magnetic stimulation in persistent somatoform pain disorder (psychosomatic pain): A narrative review

Background: Persistent somatoform pain disorder (PSPD) is a chronic bodily pain condition associated with psychological and emotional distress. It is highly comorbid with other psychiatric disorders and up to 50% or more of the general population report one or more somatic symptoms in their lifetime. Transcranial magnetic stimulation (TMS) has been proven as a safe and effective cortical stimulation technique to alleviate the symptoms in chronic pain conditions. Aim: With this narrative review, we planned to evaluate all the existing studies to know the efficacy and tolerability of TMS in patients with PSPD. Materials and Methods: The review has been registered with the International Prospective Register of Systematic Reviews (PROSPERO). On the basis of predefined selection criteria, 13 studies were found to be related to TMS in somatoform pain. Upon further screening, a total of 7 potentially relevant studies (n = 445) were included in this review. Results: The result outcomes reflect a reduction in pain perception and pain intensity in the TMS group. There was also subjective improvement in associated symptoms such as low mood, anxiety, and dysfunction. However, there were considerable variations in study parameters such as hypothesis, stimulation protocol, and study methodology, which may have impacted the final review outcomes. Conclusion: TMS is an effective and safe treatment for PSPD, but the evidence is still anecdotal and theta burst stimulation can be a potential better option than conventional TMS. There is a need for larger, longer, and possibly multicentric replication of trials with TMS and PSPD.