What psychiatric comorbidity in chronic pain? New insights for an "old," underestimated issue

BACKGROUND: Prevalence of mental disorders in chronic pain varies widely across studies and can be overestimated using screening tools. The main aims of this cross-sectional investigation were to estimate baseline prevalence of previous clinically assessed psychiatric comorbidity in a chronic pain population during their first contact within an Italian specialist pain clinic, and to examine differences in socio-demographic, clinical, and pain features between patients with and without this comorbidity. An additional aim was to explore prevalence of current psychopathology in the subgroup without psychiatric comorbidity. METHODS: One-hundred-seventy-two participants were enrolled within the “Pain Therapy Service” at the Parma University Hospital. They completed the Brief Pain Inventory (BPI) and the Millon Clinical Multiaxial Inventory-III edition (MCMI-III). Inter-group comparisons were analyzed using the χ2 or the Mann-Whitney U Test. RESULTS: Thirty-one (18%) participants had a previous clinically assessed psychiatric comorbidity, especially depressive disorder (9.9%). Comorbid patients were more likely to be unemployed and to have longer pain duration, higher BPI severity and interference scores, and fixed-dose analgesic treatment. They also had a greater prevalence of current major depression. Notably, 51.8% (N.=73) of individuals without psychiatric comorbidity showed MCMI-III scores indicative of the current presence of clinically relevant psychiatric syndromes, especially anxiety and somatoform disorders. CONCLUSIONS: Although psychiatric illnesses are more frequent among patients with chronic pain than in the general population, a large proportion of them remain undiagnosed and potentially undertreated. A stable presence of mental health professionals within multidisciplinary teams for chronic pain treatment is recommended.