0660 SUBGROUP OF NARCOLEPSY TYPE 2: CHARACTERISTICS OF SLEEP VARIABLES IN HYPERSOMNIA PATIENTS WITH ATTENTION-DEFICIT HYPERACTIVITY DISORDER (ADHD)

Abstract

Patients with attention-deficit hyperactivity disorder (ADHD) have been reported to suffer from subjective and objective sleepiness, and sleepiness is suggested to have pathophysiological relevance to ADHD. Narcolepsy type 2 is reported to be heterogeneous, therefore, we examined the influence of ADHD pathophysiology in narcolepsy type 2. The aim of the present study was to (1) examine sleep variables in hypersomnia patients with ADHD and without ADHD, (2) characterize the narcolepsy type 2 associated with ADHD and (3) explore the correlation of ADHD symptoms with objective and subjective sleepiness. Subjects were 156 consecutive outpatients with hypersomnia diagnosed by standard polysomnography (PSG) and the multiple sleep latency test (MSLT). Patients with narcolepsy type 1, sleep related breathing disorder, or periodic leg movements disorder were excluded. We subdivided hypersomnia patients (narcolepsy type 2; n = 28, idiopathic hypersomnia; n = 41) into patients with ADHD (n = 22) based on DSM-5 and patients without ADHD (non-ADHD) (n = 47) and compared sleep variables on PSG and MSLT. Correlation between the Adult ADHD Self-Report Scale (ASRS), Japanese Epworth Sleepiness Scale (J-ESS) and mean sleep latency on MSLT were examined. Hypersomnia patients with ADHD showed higher percentage of having multiple SOREMPs on MSLT (p < 0.05). In narcolepsy type 2 patients, there was no difference in the percentage of having SOREMP on PSG between patients with ADHD and non-ADHD. The percentages of having REM related symptoms and having HLA positivity were not different between the two groups. There was a correlation between ASRS and J-ESS scores (r = 0.431, p < 0.01) in non-ADHD patients, but not in ADHD patients. Hypersomnia patients with ADHD showed frequent REM transitions only in daytime. This frequent REM transitions may be a characteristic marker of ADHD and this may form one subgroup of narcolepsy type 2. ADHD symptoms may be the consequence of sleepiness in non-ADHD patients, whereas ADHD symptoms (inattention) in ADHD patients might be intrinsic rather than secondary symptoms.