Misdiagnoses and Comorbidities Among Participants in the Nexus Narcolepsy Registry

Background: Narcolepsy diagnosis can be challenging. Presence of comorbidities and overlapping symptoms between narcolepsy and other conditions may contribute to diagnostic delay and misdiagnosis.

Objective: To describe the frequency of misdiagnoses and comorbidities in participants diagnosed with narcolepsy.

Methods: The Nexus Narcolepsy Registry is an ongoing, longitudinal, patient-reported, web-based database of adult participants diagnosed with narcolepsy. Data for these analyses was collected from June 2015-September 2017, with 1024 participants completing ≥1 assessment. Participants were categorized based on pediatric (<18 years) or adult (≥18 years) onset of narcolepsy symptoms. Descriptive analyses and Chi-square tests were conducted to assess patients’ misdiagnoses and comorbidities in both groups.  

Results: Nearly 60% (59.3%; 95% CI: 56.2%-62.5%) of participants reported receiving ≥1 misdiagnosis to explain their narcolepsy symptoms before receiving a narcolepsy diagnosis. The most common misdiagnoses, regardless of age of onset, included: depression (31.3%), anxiety disorder (16.3%), attention deficit hyperactivity disorder (ADHD, 16.2%), insomnia (14.4%), and hypersomnia (14.3%). Of the most common misdiagnoses, ADHD was more frequent in pediatrics than adults (19.2% vs. 12.3%, p=0.005), as was bipolar disorder (14.2% vs. 9.1%, p=0.019). The most frequently reported comorbidities, regardless of age of onset, were: depression (34.0%), anxiety disorder (27.1%), obstructive sleep apnea (OSA, 11.6%), hypersomnia (9.9%), and ADHD (9.6%). Of the most common comorbidities, OSA occurred more frequently among those with adult symptom onset (14.2%) versus pediatric symptom onset (9.6%; p=0.033).

Conclusions: The findings were consistent with what has been reported in the literature; patients may be misdiagnosed and/or have various comorbidities, including psychiatric conditions.