Background and objective: People with fibromyalgia (FM) often report having difficulty with emotional identification and expression, and this "alexithymia" may contribute to their pain and other symptoms. Multiple studies have assessed alexithymia in FM, and we systematically reviewed and meta-analyzed this literature to: (a) describe the prevalence of alexithymia in people with FM; (b) compare the level of alexithymia in FM to both healthy controls and controls with other pain conditions; and (c) determine the association of alexithymia to pain intensity, depression, and anxiety in people with FM.

Databases and data treatment: Following PRISMA guidelines, we searched multiple databases (Scopus, PubMed/MEDLINE, Embase, Web of Science, PsycINFO and Google Scholar) from inception to May 31, 2022. Study quality was assessed with The Joanna Briggs Institute (JBI) tools for cross-sectional studies, and STATA:17 was used for meta-analysis. A total of 32 studies met eligibility criteria and were included in meta-analyses.

Results: The prevalence of alexithymia in FM averaged 48%. People with FM had substantially higher alexithymia than healthy controls (SMD = 1.00; 95% CI: 0.79 to 1.22), as well people with other pain-related conditions (SMD = 0.35, 95% CI = 0.04 to 0.65), particularly rheumatoid arthritis (SMD = 0.49; 95% CI: 0.08-0.91). Alexithymia was positively associated with pain intensity (r = 0.24), anxiety (r = 0.50), and depression (r = 0.41) among people with FM.

Conclusions: Due to the high level of alexithymia in people with FM and the positive relationship of alexithymia with pain and psychological distress, interventions to improve emotional awareness, expression, and processing in FM are recommended.