Personality disorders in patients with fibromyalgia

Area of Science:

• Psychiatry
• Epidemiology
• Internal Medicine

Background:

• Fibromyalgia (FM) frequently co-occurs with mental health conditions.
• Limited population-level data exists on the prevalence and long-term incidence of personality disorders (PDs) in individuals with FM.

Purpose of the Study:

• To quantify the cross-sectional prevalence and 20-year cumulative incidence of PD diagnoses in FM patients compared to matched controls.
• To assess the impact of diagnostic opportunity on observed PD rates in FM.

Main Methods:

• A retrospective matched-cohort study was conducted using a nationwide Israeli health system database.
• 15,869 adults with FM were matched 1:5 to 79,345 controls, comparing ICD-10 PD diagnoses over 20 years.
• Statistical analyses included conditional logistic regression and survival analysis, with a sensitivity analysis for surveillance bias.

Main Results:

• Individuals with FM showed significantly higher prevalence of any PD at baseline (1.84% vs 0.49%) and end-of-follow-up (2.85% vs 0.57%), with notable elevations in Cluster B PDs, especially borderline PD.
• The 20-year cumulative incidence of PDs was substantially higher in the FM cohort (1.03% vs 0.08%), driven by Cluster B disorders.
• Surveillance calibration indicated that the excess risk of Cluster B PDs in FM was only partly explained by increased psychiatric service utilization.

Conclusions:

• Fibromyalgia is associated with a significant and enduring increase in Cluster B personality disorders, particularly borderline PD.
• These findings support the integration of routine PD screening into FM management protocols.
• Further research is recommended to explore the underlying immuno-neuroendocrine and frontolimbic mechanisms linking FM and PDs.