Comorbid psychiatric disorders among patients with narcolepsy.

Purpose: This case-control study assessed the prevalence of psychiatric disorders in Arab (Saudi) patients with narcolepsy using a structured clinical interview.

Methods: The study included 74 adult patients with narcolepsy and 265 controls matched for age and sex. Narcolepsy diagnosis was made according to the International Classification of Sleep Disorders-Third Edition. Psychiatric disorders were diagnosed via using a validated Arabic version of the Mini International Neuropsychiatric Interview DSM-IV (MINI version 6). A multivariate logistic regression model was used to assess the potential influence of narcolepsy on the comorbidity of psychiatric disorders.

Results: The mean age of the patients was 29.4 ± 10.2 years, and males accounted for 81% of the study sample. Forty-four patients (60%) were diagnosed with narcolepsy type-1 (NT1) and 30 (40%) with narcolepsy type-2 (NT2). Psychiatric disorders were diagnosed in 45% of patients with narcolepsy compared with 15% of the controls (p < 0.001). The multivariate logistic regression models demonstrated that compared with the controls, patients with narcolepsy were more likely to have major depressive disorders (OR, 4.3 [CI, 2.2-8.2]), and generalized anxiety disorders (OR, 9.5 [CI, 1.8-50.2]). No difference was detected between the prevalence of various psychiatric disorders in patients with NT1 and NT2.

Conclusion: Comorbid psychiatric disorders are common among Arab (Saudi) patients with narcolepsy compared with the general population. Therefore, clinicians should be aware of the comorbidity of narcolepsy and psychiatric disorders, particularly depression.