Role of psychiatric comorbidity in chronic Lyme disease.

OBJECTIVE

To evaluate the prevalence and role of psychiatric comorbidity and other psychological factors in patients with chronic Lyme disease (CLD).

METHODS

We assessed 159 patients drawn from a cohort of 240 patients evaluated at an academic Lyme disease referral center. Patients were screened for common axis I psychiatric disorders (e.g., depressive and anxiety disorders); structured clinical interviews confirmed diagnoses. Axis II personality disorders, functional status, and traits like negative and positive affect and pain catastrophizing were also evaluated. A physician blind to psychiatric assessment results performed a medical evaluation. Two groups of CLD patients (those with post-Lyme disease syndrome and those with medically unexplained symptoms attributed to Lyme disease but without Borrelia burgdorferi infection) were compared with 2 groups of patients without CLD (patients recovered from Lyme disease and those with an identifiable medical condition explaining symptoms attributed to Lyme disease).

RESULTS

After adjusting for age and sex, axis I psychiatric disorders were more common in CLD patients than in comparison patients (P = 0.02, odds ratio 2.64, 95% confidence interval 1.30-5.35), but personality disorders were not. Patients with CLD had higher negative affect, lower positive affect, and a greater tendency to catastrophize pain (P < 0.001) than comparison patients. All psychological factors except personality disorders were related to level of functioning. A predictive model based on these psychological variables was confirmed. Fibromyalgia was diagnosed in 46.8% of CLD patients.

CONCLUSION

Psychiatric comorbidity and other psychological factors distinguished CLD patients from other patients commonly seen in Lyme disease referral centers, and were related to poor functional outcomes.