Polysomnographic and Clinical Characteristics of Narcolepsy in Saudi Arabia: A 12-Year Retrospective Study

To evaluate the clinical features, polysomnographic findings, and therapeutic outcomes of narcolepsy type 1 and type 2 patients in Kingdom of Saudi Arabia (KSA). Narcolepsy is a neurological condition marked by excessive daytime sleepiness (EDS) and associated symptoms, including cataplexy and disrupted nighttime sleep. Data on narcolepsy in KSA are still limited.

Forty-three patients diagnosed with narcolepsy from 2012 to 2024 were included in this retrospective study. Diagnosis followed the International Classification of Sleep Disorders criteria and incorporated clinical features, the epworth sleepiness scale (ESS), overnight polysomnography (PSG), and multiple sleep latency testing (MSLT). Data on demographics, clinical symptoms, PSG parameters, and treatment were analyzed. Posttreatment ESS scores were collected via an electronic survey.

All patients reported EDS, and 53.5% had cataplexy. Time of diagnosis mean age was 28.9 ± 14.4 years, with a diagnostic delay of 5.3 ± 3.0 years. Patients with narcolepsy type (NT)1 had significantly higher baseline ESS scores (19.6 versus (vs.) 16.9, p = 0.031) and shorter mean sleep latency (2.1 vs. 4.3 minutes, p = 0.008). Treatment, predominantly with modafinil (69%), significantly reduced ESS scores from 18.4 ± 4.2 to 9.2 ± 2.4 (p < 0.001).

Compared with NT2, NT1 is slightly more common and is characterized by more severe sleepiness and shorter sleep latency time. The diagnostic delay remains substantial, but treatment is effective in reducing EDS.