Attention deficit/hyperactivity disorder (ADHD) is a common childhood-onset psychiatric condition, characterized, according to the DSM-5 criteria (American Psychiatric Association, 2013), by impairing and pervasive core symptoms of inattention and/or hyperactivity–impulsivity. Impairing symptoms of ADHD persist into adulthood in as many as 65% of cases (Mannuzza, Klein, & Moulton, 2003). The association between ADHD and other psychiatric or neurodevelopmental conditions such as oppositional defiant disorder (ODD), conduct disorder (CD), and mood/anxiety disorders, is well-established (Biederman & Faraone, 2005).

Conversely, the relationship between ADHD and sleep disturbances has been largely overlooked, both from a research standpoint and in clinical practice. This is reflected by the lack of specific recommendations on sleep assessment in a number of previous guidelines and practice parameters on ADHD over the last decade (Pliszka & AACAP Work Group on Quality Issues, 2007). However, sleep problems are an important factor to consider in the assessment and management of patients with ADHD. Indeed, when asked, parents of children with ADHD do report sleep problems in their children in a sizable portion of cases. According to Corkum, Tannock, & Moldofsky, 1998, parents report sleep problems in 25%–50% of children with ADHD, compared with 7% of normal controls. Considering also mild (besides severe) sleep alterations, 70% of children with ADHD have been found to present with a parent-reported sleep problem (Sung, Hiscock, Sciberras, & Efron, 2008). Of note, in more recent years there has been an increasing awareness of sleep problems in children with ADHD, as reflected by the inclusion of sleep evaluation in some of the more recent ADHD guidelines and consensus statements, both in children and in adults (Kooij et al., 2010; Subcommittee on Attention-Deficit/Hyperactivity Disorder et al., 2011; Díaz-Román 2016).

Addressing sleep issues in patients referred for ADHD symptoms is of particular relevance for three reasons (Konofal, Lecendreux, & Cortese, 2010): (1) Sleep disturbances may represent a significant source of distress for the child and/or the family; (2) sleep problems may worsen ADHD symptoms as well as associated mood and emotional disorders; and (3) quantitative or qualitative alterations of sleep may cause problems with mood, attention, and behavior, so that sleep disturbances may mimic ADHD symptoms and result in misdiagnosis of children with ADHD. Therefore, symptoms of inattention, hyperactivity and/or impulsivity may be improved or even eliminated with treatment of the primary sleep disorder.

Sleep dysfunction in individuals with ADHD is underpinned by a multifactorial etiopathophysiology (Pliszka & AACAP Work Group on Quality Issues, 2007). As a consequence, the management needs to be tailored to the specific factors underlying sleep disturbances. In this chapter, addressed mainly to clinicians, we provide an overview of the main sleep disturbances/disorders associated with ADHD, their diagnostic assessment and available therapeutic options. We base our therapeutic recommendations on existing empirical evidence, integrating it with our clinical experience when no or limited empirical data are available.

Sleep can be assessed by means of so-called “subjective methods,” that is, clinical interviews or questionnaires filled out by the patient (in pediatric settings, by the parents or, less frequently, by the children themselves) or “objective” methods, that is, using neurophysiological tools such as polysomnography (PSG), actigraphy, infrared video analysis, and the multiple sleep latency test (MSLT). Several subjective (e.g., Mick, Biederman, Jetton, & Faraone, 2000) as well as objective sleep studies (e.g., Kirov, Banaschewski, Uebel, Kinkelbur, & Rothenberger, 2007) have been conducted in ADHD. It is unpractical to review all these studies here. Fortunately, meta-analytic evidence pooling all pertinent studies is available, both for studies including children and adults. In our review, we found evidence that children with ADHD present with significantly more sleep problems than youth without ADHD as reported by parents, including bedtime resistance, sleep onset difficulties, night awakenings, difficulties with morning awakenings, sleep disordered breathing (SDB), and daytime sleepiness (Cortese, Faraone, Konofal, & Lecendreux, 2009). We also found that children with ADHD were significantly more compromised than comparisons in several parameters from objective studies, such as sleep onset latency (on actigraphy), the number of stage shifts/hour sleep, the apnea–hypopnea index, and sleep efficiency on PSG, true sleep time on actigraphy, and average times to fall asleep for the MSLT than the comparisons (indicating that children with ADHD have higher levels of daytime sleepiness than comparisons). Of note, we excluded studies assessing children pharmacologically treated or with comorbid anxiety/depressive disorders, thus suggesting that the significant differences in sleep parameters (both subjective and objective) are not accounted for exclusively by ADHD medications or psychiatric comorbidities, although of course these factors may and do impact sleep in children with ADHD (see Table 9.1 for suggestions on how to manage sleep problems possibly associated with ADHD medication use). As for adults, a more recent meta-analysis found that, compared to adults without ADHD, those with ADHD significantly differed in seven out of nine subjective parameters and two out of five actigraphic parameters (sleep onset latency and sleep efficiency) (Díaz-Román, Mitchell, & Cortese, 2018).

In the following sections, we discuss the assessment and the management of sleep disturbances in individuals with ADHD.

Given the association between sleep disturbances and ADHD, we suggest to systematically screen for sleep problems at first visit as well as at each visit of follow-up. Based on the aforementioned considerations, it is paramount to systematically inquire for sleep problems not only in patients with an established diagnosis of ADHD, but also in those referred for symptoms of inattention and/or hyperactivity–impulsivity, in order to rule out possible sleep disorders such as restless leg syndrome (RLS) or SDB that may mimic ADHD. A simple screening can be implemented using a series of open, unstructured questions (see Chapter 8). The following aspects should be inquired: bedtime resistance, sleep onset difficulty, night awakenings, difficulty with morning awakenings, SDB, and daytime sleepiness. Besides clinical interviews, several tools are available to help the clinician screen for sleep problems and orient further assessment. For children, these include the Sleep Disturbance Scale for Children (Bruni et al., 1996), the Pediatric Sleep Questionnaire (Chervin, Hedger, Dillon, & Pituch, 2000), and the Children’s Sleep Habit Questionnaire (Owens, Spirito, & McGuinn, 2000). We note that these questionnaires do not include a systematic screening for RLS, in part because this syndrome has been described in children only recently. In this regard, the clinician can refer to the criteria for RLS proposed at the 1995 restless legs syndrome diagnosis and epidemiology workshop at the National Institutes of Health (Allen et al., 2003), as well as the recent Pediatric Restless Legs Syndrome Severity Scale (P-RLS-SS) (children and parent version) (Arbuckle et al., 2010), which allows the quantification of the severity and the impact of RLS symptoms in children. For adults, screening tools include the Pittsburgh Sleep Quality Index (Buysse, Reynolds, Monk, Berman, & Kupfer, 1989), the Berlin Questionnaire to identify patients at risk for the sleep apnea syndrome (Netzer, Stoohs, Netzer, Clark, & Strohl, 1999) and the Epworth sleepiness scale (Johns, 1991) for measuring daytime sleepiness (see Chapter 8). Besides questionnaires, another subjective tool is the sleep diary (somnolog, see also Chapter 8), where the patient (or the parents in case of children) records sleeping and waking times over a period of some weeks (in our experience: 3 weeks). It is relatively feasible to incorporate each of the aforementioned subjective tools in the first as well as the follow-up visits. We suggest performing a PSG recording if there is a suspicion of SDB, nocturnal convulsions, sleep related causes of excessive daytime sleepiness or sleep fragmentation due to frequent nocturnal arousals (including Periodic Limb Movement Disorder, see Chapter 8). MSLT preceded by all-night PSG should be considered to evaluate daytime sleepiness secondary to sleep alterations or as an expression of a primary alteration of arousal as well as to rule out narcolepsy as a differential diagnosis

Clearly, referred patients present not with a diagnosis of sleep disorder but with sleep complaints which are nonspecific. For example, bedtime resistance, which, in our experience, is the most common sleep complaint associated with ADHD, may be due to limit setting disorder, RLS, delayed sleep phase onset, or anxiety. Thus, the appropriate management of sleep complaints in patients with ADHD relies on the correct identification and treatment of sleep disorder(s) or alterations underlying these complaints. In this regard, the goal is to perform an accurate diagnosis using subjective and, when necessary, objective tools. For the diagnosis, we refer to the criteria of the International Classification of Sleep Disorders, third edition (American Academy of Sleep Medicine, 2014), which includes also specific criteria for children. The therapeutic strategies of sleep complaints should be tailored to the specific underlying disorder. In our experience, it is not infrequent to find ADHD patients with more than one sleep disorder (e.g., limit setting disorder and sleep phase delay).