Somatic Symptom and Related Disorders and Mild Traumatic Brain Injury: A Systematic Review

Objective: A comprehensive systematic review of the relationship between somatic symptom and related disorders (SSRD) and mild traumatic brain injury (mTBI). Methods: Searches for SSRD, mTBI and related terms were performed and combined from the following databases on March 7 th , 2024: Ovid MEDLINE, Cochrane Central Register of Controlled Trials, CINAHL, SPORTDiscus, PsycINFO, Embase, and Scopus. Studies were included if they met the following criteria: (a) recruitment of human participants; (b) diagnosis of SSRD or validated measure of somatization (c) reported on patients meeting diagnostic criteria for mTBI; (d) evaluated an association between mTBI and SSRD as a main outcome (e) published in a peer-reviewed journal; (f) published before March 7 th , 2024. Each of these studies were assessed for risk of bias using the Scottish Intercollegiate Guidelines Network (SIGN) criteria checklist. Results: Out of 6,009 unique titles and abstracts, 192 full manuscripts were screened, and 43 studies were included. Of these, 9 studies reported associations between functional seizures and history of mTBI. Thirty-one studies assessed relationships between questionnaires assessing SSRD burden (e.g., Patient Health questionnaire-15) and mTBI. Three studies investigated healthcare practitioner diagnosis of SSRD and post-mTBI symptom burden. Thirty-six studies of the 43 studies reviewed had a risk of bias rating of unacceptable, 4 were considered high quality and another 3 were considered acceptable risk of bias. Conclusion: The majority of the acceptable evidence supported a relationship between SSRD and mTBI. However, there were few acceptable or high-quality studies available and further research on this topic is needed.