Elsevier

Sleep Medicine

Volume 14, Issue 6, June 2013, Pages 488-492
Sleep Medicine

Original Article
Narcolepsy is complicated by high medical and psychiatric comorbidities: a comparison with the general population

https://doi.org/10.1016/j.sleep.2013.03.002Get rights and content

Abstract

Background

Individuals affected with narcolepsy represent a vulnerable segment of the population. However, we only have a partial understanding of this vulnerability. Our study aims to examine psychiatric disorders and medical conditions associated with narcolepsy.

Methods

A total of 320 narcoleptic participants were interviewed regarding sleeping habits, health, medication consumption, medical conditions (International Statistical Classification of Diseases and Related Health Problems, 10th edition), sleep disorders (International Classification of Sleep Disorders, second edition [ICSD-2]) and mental disorders (Diagnostic and Statistical Manual of Mental Disorders, fourth edition, text revision [DSM-IV-TR]) using Sleep-EVAL. A general population comparison sample (N = 1464) matched for age, sex, and body mass index (BMI) and interviewed with the same instrument was used to estimate odds ratios (OR).

Results

Five diseases were more frequently observed among narcoleptic participants, including hypercholesterolemia (OR, 1.51), diseases of the digestive system (OR, 3.27), heart diseases (OR, 2.07), upper respiratory tract diseases (OR, 2.52), and hypertension (OR, 1.32). Most frequent psychiatric disorders among the narcolepsy group were major depressive disorder (MDD) (OR, 2.67) and social anxiety disorder (OR, 2.43), both affecting nearly 20% of narcoleptic individuals. However, most mood and anxiety disorders were more prevalent among the narcoleptic group. Alcohol abuse or alcohol dependence was comparable between groups.

Conclusions

Narcolepsy is associated with a high comorbidity of both medical conditions and psychiatric disorders that need to be addressed when developing a treatment plan.

Introduction

Narcolepsy is a debilitating neurodegenerative disorder characterized by daytime sleep attacks and rapid eye movement (REM) sleep abnormalities (e.g., sleep-onset REM periods, sleep paralysis, hypnagogic hallucinations). Narcolepsy is a rare disorder affecting less than 0.05% of the general population [1]. However, impacts on daytime functioning are considerable and many affected individuals have severe limitations in their daily life activities [2]. Some studies have reported a poorer health-related quality of life, as measured by the Short Form (36) Healthy Survey in narcoleptic patients when compared to the general population [3], [4]. However, quality of life for these individuals tends to improve over time [4], possibly due to adaptation strategies for coping with the impact of the disease [4], [5].

Individuals affected by narcolepsy represent a vulnerable segment of the population. However, we only have a partial understanding of this vulnerability. Narcoleptic individuals often have morbid obesity, and several also have sleep apnea syndrome (up to 25%) [6]. Both conditions put these individuals at greater risk for developing other serious health concerns such as cardiovascular diseases. Unfortunately, few studies have examined which health conditions and psychiatric disorders are associated with narcolepsy [7], [8]. Understanding comorbid conditions associated with narcolepsy is of utmost importance when devising an appropriate treatment plan. Our study aims to present a detailed look at the mental and organic health concerns that affect narcoleptic individuals when compared with a matched general population sample.

Section snippets

Narcolepsy sample

A total of 320 narcoleptic participants were included in the study. Most of them were referred by sleep specialists. Twenty-two participants came from the general population and were diagnosed with narcolepsy by a sleep specialist.

General population sample [9]

Fifteen states were selected to represent the US population based on the number of residents and geographic area. The 15 states that were included were Arizona, California, Colorado, Florida, Idaho, Missouri, New York, North Carolina, North Dakota, Oregon,

General description of the samples

The narcolepsy sample was composed of 109 men and 211 women. The mean age was 40.27 (±14.73) years and the BMI was 28.53 (±6.78). Half of the participants were married (50.3%) and working (55.6%). Most of them were white (82.3%). The matched general population sample included 472 men and 992 women. The mean age was 43.78 (±14.57) years, and the BMI was 26.79 (±3.98). Half of them were married (50.9%) and most were working (66.1%). Most of them also were white (78.6%).

Comorbid organic conditions

Table 1 presents the most

Discussion

Our study clearly illustrates the medical history complexity of individuals with narcolepsy. In addition to having a debilitating disease, most of the narcoleptic participants also had at least one medical condition or a psychiatric disorder that required treatment. We found that a large number of narcoleptic individuals (27.5%) also had upper respiratory tract diseases, mainly asthma and allergies, which would indicate a compromised immune system. A few years ago, it was hypothesized that the

Conflict of interest

The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2013.03.002.

. ICMJE Form for Disclosure of Potential Conflicts of Interest form.

Acknowledgment

This study was supported by a grant from the National Institutes of Health (R01NS044199), the Arrillaga Foundation, and an unrestricted educational grant from Jazz Pharmaceuticals.

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