Chronic pain in mental disorders: an umbrella review of the prevalence, risk factors, and treatments across 957,168 people with mental disorders and 16,606,910 controls

Background Chronic pain (CP) and mental disorders often coexist, yet their relationship lacks comprehensive synthesis. This first hierarchical umbrella review examined systematic reviews and meta-analyses, also observational studies and randomized controlled trials (where reviews are currently lacking) to report CP prevalence, risk factors, and treatment across mental disorders. Methods We searched MEDLINE, PsycINFO, Embase, Web of Science, and CINAHL, identifying 20 studies on anxiety, depression, bipolar disorder, schizophrenia, ADHD, autism, or dementia, and CP. Quality was assessed using AMSTAR and Newcastle-Ottawa Scale. Results Prevalence varied widely - 23.7% (95% CI 13.1-36.3) in bipolar disorder to 96% in PTSD - consistently exceeding general population rates (20-25%). Risks were elevated, with bidirectional links in depression (OR = 1.26-1.88). Risk factors included female gender, symptom severity, and socioeconomic disadvantage, though data were limited beyond PTSD and depression. Treatment evidence was sparse: cognitive behavioral therapy showed small effects on pain (SMD = 0.27, 95% CI -0.08-0.61), acupuncture with medication improved pain (MD = -1.06, 95% CI -1.65 - 0.47), and transcranial direct current stimulation reduced pain in dementia (d = 0.69-1.12). Methodological issues were evident, including heterogeneous designs and inconsistent pain definitions. Conclusions This review confirms CP as a significant comorbidity in mental disorders. Clinicians should prioritize routine pain screening and multimodal treatments. Researchers need longitudinal studies with standardized assessments to clarify causality and improve interventions. Taken together, this work highlights an urgent need for integrated psychiatric care approaches, emphasizing that addressing CP could enhance mental health outcomes and overall patient well-being.