Psychiatric comorbidity patterns across disability-based fibromyalgia phenotypes

Abstract

Objective
Fibromyalgia (FM) is a heterogeneous chronic pain condition frequently accompanied by psychiatric symptoms. Although affective symptoms are highly prevalent, they are often treated as secondary correlates of pain or disability. This study examined whether psychiatric symptom profiles parallel disability severity or represent partially independent dimensions across disability-based FM phenotypes.


Methods
We analyzed a harmonized multisite cohort of adults with FM recruited from two academic medical centers. Disability-based phenotypes were defined using a validated percentile-based classification dichotomizing participants into low-impact and high-impact FM. Psychiatric domains were derived from standardized measures of depressive and anxiety-related symptoms. Multivariate clustering was used to identify affective profiles, and their distribution across disability phenotypes was examined. Dimensional analyses assessed the relationship between affective burden and functional impairment.


Results

Among participants with complete psychiatric data (
n
 = 613), four reproducible affective profiles were identified: minimal affective symptoms, mild affective symptoms, moderate mixed affective symptoms, and severe mixed affective symptoms. Although profiles characterized by greater affective burden were enriched among individuals with high-impact FM, all affective profiles were represented across both disability groups. Notably, a substantial proportion of individuals with high-impact FM exhibited minimal or mild affective symptoms. Dimensional analyses supported partial orthogonality between affective burden and disability severity.



Conclusions
Psychiatric comorbidity in FM does not simply reflect pain severity or functional impairment. Instead, affective symptoms form partially independent dimensions that cut across disability-based phenotypes. These findings support a multidimensional neuropsychiatric framework for FM with implications for stratified assessment and personalized intervention.