OBJECTIVE: To investigate the prevalence of core attention-deficit/hyperactivity disorder (ADHD) symptoms in Chinese narcolepsy type 1 (NT1) patients and to explore mood, quality of life, and executive function in narcolepsy patients with or without ADHD and the response to Methylphenidate Hydrochloride Extended-release tablets (ER-MPH) treatment.
METHOD: A total of 267 pediatric NT1 patients (194 males and 73 females, 5-17 years old) were evaluated for ADHD symptoms by a psychiatrist using the DSM-IV diagnostic criteria of the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI Kid) from February 2011 to July 2013 at Peking University People's Hospital. All patients underwent Stanford Sleep Inventory (SSI) evaluation and polysomnography followed by multiple sleep latency tests (MSLT) before ER-MPH treatment. Neuropsychological evaluations, including the Inventory of Subjective Life Quality (ISLQ), Depression Self-resting Scale for Children (DSRS-C), Screening for Child Anxiety-related Emotional Disorders (SCARED) and Barratt Impulsiveness Scale (BIS), were performed before and after 16 weeks of ER-MPH treatment. Executive abilities were assessed by the Behavior Rating Inventory of Executive Function-parent version (BRIEF-P). The narcolepsy symptoms, evaluated by the Pediatric Sleep Questionnaire (PSQ), and ADHD symptoms were assessed before and after treatment in NT1 patients with ADHD.
RESULT: Seventy-seven of 267 (28.8%) NT1 patients had ADHD symptoms, with 73 patients being inattentive type (ADHD-I) and 4 patients being combined type (ADHD-C). Despite similar objective sleep parameters, NT1 patients with ADHD symptoms experienced higher anxiety levels, more impulsive behaviors, lower health-related quality of life and worse executive functions than those without ADHD (p<0.05). Methylphenidate treatment was effective in improving daytime sleepiness in NT1 patients with ADHD (PSQ, 16.7 ± 2.1 vs 13.5 ± 1.9, p<0.05) but was ineffective on ADHD symptoms (ADHD-RS, 25.3 ± 9.1 vs 26.4 ± 8.9, p>0.05).
CONCLUSION: A high prevalence of ADHD (28.8%) was identified in children and adolescents with NT1. Comorbid ADHD symptoms were associated with increased levels of mood disorders and lower quality of life. ER-MPH treatment could reduce daytime sleepiness but not ADHD symptoms in narcolepsy patients with ADHD, suggesting that new treatment strategies are needed for this group of patients.
