Association between symptoms and subtypes of attention-deficit hyperactivity disorder and sleep problems/disorders

This study aimed to investigate the association between attention-deficit hyperactivity disorder (ADHD) symptoms and subtypes, and sleep schedules, daytime inadvertent napping, and sleep problems/disorders in children and adolescents with and without ADHD. The sample included 325 patients with ADHD, aged 10-17 years [male: 81.5%; combined type (ADHD-C): 174; predominantly inattentive type (ADHD-I): 130; predominantly hyperactive-impulsive type (ADHD-HI): 21], and 257 children and adolescents without lifetime ADHD (non-ADHD). We conducted psychiatric interviews with the participants and their mothers before making the diagnoses of ADHD, other psychiatric disorders, and sleep problems or disorders. We also collected the medication treatment data and parent and teacher reports of ADHD symptoms. Multi-level models were used for data analyses controlling for sex, age, psychiatric comorbidities, and treatment with methylphenidate. The ADHD-C and ADHD-I groups had more daytime inadvertent napping. In general, the three subtypes were associated with increased rates of sleep problems/disorders. Specifically, ADHD-C rather than ADHD-I was associated with circadian rhythm problems, sleep-talking, nightmares (also ADHD-HI), and ADHD-I was associated with hypersomnia. The most-related sleep schedules and problems for inattention and hyperactivity-impulsivity were earlier bedtime, later rise time, longer nocturnal sleep, more frequent daytime napping, insomnia, sleep terrors, sleep-talking, snoring, and bruxism across informants. The findings imply that in addition to the dichotomous approach of ADHD and considering the psychiatric comorbid conditions, ADHD subtypes and symptom dimensions need to be considered in clinical practice and in the research regarding the association between ADHD and sleep problems/disorders.