Generally, it is recommended that children obtain age-appropriate sleep duration through appropriately set bedtimes, wake times and nap times, and that these sleep schedules are consistent across days including weekdays and weekends. The U.S. National Sleep Foundation recommends that toddlers (1–2 years of age) obtain 11–14 hours of sleep, preschoolers (3–5 years of age) obtain 10–13 hours of sleep, and school-aged children (6–13 years old) obtain 9–11 hours of sleep (Hirshkowitz et al., 2015). Generally, toddlers nap once or twice a day for approximately 2 hours total time. Approximately, half of preschoolers do not nap, and the ones that do nap typically have one nap per day for 1–2 hours. Very few school-aged children nap (Mindell, 2005). Furthermore, it has been recommended that children go to sleep before 9:00 p.m. and that there is no more than 30–60 minutes difference between bedtimes and wake times throughout the week. While these recommendations are thought to be among the most important recommendations, there is only a small body of research that evaluates the impact of these recommendations on sleep outcomes. Based on the systematic review by Allen et al. (2016), there was strong evidence for the importance of an age-appropriate sleep duration, moderate evidence for the timing of sleep (e.g., before 9:00 p.m. bedtimes and consistent schedules), and only limited support for the recommendation of no more than 30–60 minutes differences in bedtimes and wake times across the week.

For children with ADHD, there is mixed evidence regarding whether they obtain age-appropriate sleep duration. Some studies have found that they receive less sleep than their typically developing peers and less sleep than recommended, while other studies have found that they sleep longer than their peers and within the recommended amounts (Corkum & Coulombe, 2013). These mixed findings may in part be related to other factors such as comorbidities (e.g., whether the child has another disorder such as anxiety or depression, both of which have been associated with increased sleep difficulties) or treatment with stimulant medication (e.g., although there are mixed results, the most consistent finding is that stimulant medications delay sleep onset and as such shorten sleep duration). Children with ADHD have been reported to have an evening chronotype (otherwise known as being “night owls”) and consequently have later bedtimes than their typically developing peers (Durmuş, Arman, & Ayaz, 2017). This evening chronotype has been associated with increased sleep problems such as resistance to bedtime (Durmuş et al., 2017). Very little research has been conducted examining napping in children with ADHD, in part because this disorder is usually diagnosed in school-aged children at which age most children are no longer napping. However, one study found that children with ADHD (the Inattentive and Combined presentations) were more likely to have inadvertent naps than the typically developing group (Chiang et al., 2010). In fact, they found that inadvertent napping was one of the most highly correlated sleep problems associated with ADHD symptoms, particularly inattention symptoms. Some research has found that the regularity of sleep schedules for children with ADHD is less consistent than their typically developing peers. For example, Gruber, Sadeh, and Raviv (2000) found that relative to typically developing peers, children with ADHD demonstrated more instability across five consecutive nights of sleep in terms of sleep onset, sleep duration, and amount of true sleep. However, a study by Poirier and Corkum (2015) did not find differences in sleep stability across four nights between children with ADHD and a control group. While there are mixed findings about the duration, regularity, and consistency of sleep in children with ADHD, it does appear that these children may experience difficulties with these key healthy sleep practices, at least in some situations and for some children with ADHD.

As noted above, age-appropriate and consistent sleep times are associated with better sleep outcomes. Not only are schedules important in terms of setting bedtimes, nap times, and wake times, but they also are important throughout the day. Schedules and routines are activities that are completed in a specific order during the day and night (e.g., bedtime routine, wake time routine, meal routine, homework routine). Schedules/routines provide structure, consistency, and stability, and if these schedules are consistent they can also provide cues to regulate a child’s arousal level. For example, breakfast is an important zeitgeber, or time cue, which sends a signal to the body’s biologic clock or circadian rhythm to “gear up for the day.” One of the key ways to help children fall asleep at predetermined scheduled times is by incorporating a bedtime routine. Bedtime routines should be relatively brief (30–60 minutes), help the child to relax (e.g., not include stimulating or frustrating activities), and should limit exposure to bright light. Nap time routines should be similar to bedtime routines, but shorter in duration. Morning routines should be energetic, fun, and the environment should include exposure to bright light. All routines should be consistently implemented across all days. The review by Allen et al. (2016) found strong support for establishing bedtime routines, but insufficient support for wake time routines and consistency in daytime routines. Insufficient support does not mean these are not important, but rather there was no evidence to judge their contribution to better sleep outcomes.

The core symptoms of ADHD (i.e., inattention, impulsivity, restlessness) makes the implementation of routines challenging for parents, and also makes following routines difficult for these children (Corcoran, Schildt, Hochbrueckner, & Abell, 2017). Therefore, ADHD parenting programs, which are considered one of the evidence-based interventions for ADHD, often focus on teaching parents to develop consistent routines to improve child behavior (Lee, Niew, Yang, Chen, & Lin, 2012). A study by Harris et al. (2014) found that in homes of children with ADHD, an increase in the daily routines (e.g., homework and household duties such as chores and cleaning up after oneself) was related to fewer externalizing and internalizing behavior challenges, even after adjusting for confounding variables such as the child’s age, sex, and parental adjustment. Similar to daily routines, sleep routines may also be problematic for children with ADHD. The authors’ early research found that child–parent interactions during bedtime routines were more challenging for the ADHD group than the typically developing group (Corkum, Tannock, Moldofsky, Hogg-Johnson, & Humphries, 2001). More recently, Noble, O’Laughlin, and Brubaker (2012) found that greater bedtime resistance was associated with a lack of bedtime routines in children with ADHD. They noted that this may result in increased child–parent conflict and poorer sleep overall; however, given the correlational nature of these data, causation cannot be inferred. Rather, it could also be that greater bedtime resistance may lead to lack of bedtime routines. While there is limited research on morning routines for children with ADHD, recent research has found that mornings are a source of stress for parents of children with ADHD, particularly for children who are treated with stimulant medication (Sallee, 2015). To our knowledge, there is no research examining napping routines in this population, given that the age of diagnosis is typically in the early school-age years at which time naps have ceased. While research indicates that routines may not be as commonly implemented with children with ADHD, it is not known whether the routines are qualitatively different for this population.

Clinicians providing recommendations about healthy sleep practices often include changes to the sleep environment. Typical recommendations include sleeping in a dark, quiet, cool room on a comfortable bed, which is used exclusively for sleep. Based on Allen et al.’s (2016) review of the literature, these recommendations have limited empirical support and additional research needs to be conducted. The rationale behind the recommendation for a dark room is related to the fact that melatonin, a hormone that promotes sleep, is released in the dark (hence, it is often called the hormone of darkness). When given as a supplement, melatonin can both increase sleepiness (i.e., hypnotic effect), as well as regulate the circadian rhythm.

No research could be found specifically on the ideal sleep location characteristics for children with ADHD. However, there is some evidence that there may be subtle differences in melatonin profiles in children with ADHD compared to their typically developing peers (Nováková et al., 2011). This is more apparent in children with ADHD who also have sleep onset problems, who demonstrate delays in the release of melatonin (van der Heijden, Smits, Van Someren, & Gunning, 2005). Treatment with melatonin supplements for children with ADHD and delayed sleep onset has been shown to be effective in improving sleep onset and sleep duration but does not result in improvements in daytime behaviors (van der Heijden, Smits, Van Someren, Ridderinkhof, & Gunning, 2007).

Not allowing electronics (including TVs, computers, videogame devices, and phones) in the bedroom and limiting their use for the hour before bedtime are commonly made recommendations by health professionals. There are two potential reasons for these recommendations. Electronics emit blue light which can potentially suppress the release of melatonin. Secondly, electronics can increase arousal levels, which is in contrast to the goal of using calming activities before bedtime. Allen et al. (2016) found strong support for removing all electronics from the bedroom, but there was insufficient support for recommending no use of electronics for 1 hour before bedtime (as there was no research on this topic included in the articles reviewed by Allen et al., 2016). The mechanism by which electronics use impacts sleep has not been determined, but multiple impacts are likely, such as taking up time that should be dedicated to sleep, increased physiological arousal, and exposure to bright light that may impact the timing of the sleep–wake cycle (Cain & Gradisar, 2010).

Daytime behaviors generally thought of as healthy behaviors can impact sleep in both positive and negative ways. For example, exercise can increase the duration of slow wave (restorative) sleep, but exercise too late in the day in some children can potentially cause sleep onset insomnia. A healthy diet and eating at correct times can improve sleep but eating too close to bedtime, trying to fall asleep when hungry, or consuming caffeinated foods/drinks, can all interfere with being able to fall asleep. While these recommendations make intuitive sense, again there is limited research on the impact of these factors on sleep (Allen et al., 2016). Interestingly, in the systematic review there was lack of support for the notion that exercising too close to bedtime can result in sleep problems (Allen et al., 2016).

Recent research has found that children with ADHD (especially as adolescents and adults) are more likely to be overweight and to engage in less physical activity than their peers (Kim et al., 2014), thus potentially setting the stage for poor sleep. Moreover, a recent study examined the relationship between diet and sleep in children with ADHD and found that children with more sleep problems also ate a diet higher in carbohydrates, fats, and sugars (Blunden, Milte, & Sinn, 2011). In Monastra’s (2008) chapter on ADHD, nutrition, and exercise, the research is clearly outlined that supports the impact diet and exercise can have on daytime functioning, while also recognizing that ADHD is not caused by these factors. Monastra stresses the importance of these as targets in treatment of ADHD. While no research is available about children with ADHD and caffeine consumption, there is evidence for increased consumption of coffee in adolescents with ADHD compared to their typically developing peers (Marmorstein, 2016).

Falling asleep and sleeping restfully through the night requires a child to feel safe and relaxed. This requires that the home environment, throughout the day and particularly before bedtime, is a positive environment. Allen et al. (2016) found moderate support for this recommendation. Moreover, limited empirical evidence was found for the importance of parents to have a positive attitude toward sleep.

Compared to typically developing children, it has been shown that families of children with ADHD have higher rates of dysfunction (e.g., more conflict; Cunningham & Boyle, 2002), as well as increased daily struggles at home and school (Altepeter & Breen, 1992). Conflict and struggles are inherently negative and contradictory to a calm relaxed state. These conflicts and struggles are also more frequent in the evening than morning (e.g., Corkum, Andreou, Schachar, Tannock, & Cunningham, 2007), which would likely impact sleep in children with ADHD. Moreover, parents of children with ADHD have been found to hold beliefs that their children’s sleep problems are more intrinsic, less modifiable, and less responsive to treatment than parents of typically developing children (Goodday, Corkum, & Smith, 2014). These beliefs may make parents less likely to seek out and implement behavioral strategies to help improve their child’s sleep, although there is no empirical evidence that tests this assumption.

Allen et al.’s (2016) review of the literature found strong support for the association between independence in falling asleep and good sleep outcomes. Children who required a parent present to fall asleep or co-slept (in a reactive manner) were found to have more sleep problems, including later bedtimes, shorter sleep duration, and more night awakenings. Teaching children to fall asleep independently is a key component of many sleep interventions (Vriend et al., 2012).

There is no research available that specifically examines co-sleeping in children with ADHD. Perhaps, this is because at the time of diagnosis (which usually happens during early school years), co-sleeping is less common (less than 5% of typically developing, nonanxious school-aged children co-sleep on a regular basis; Palmer, Clementi, Meers, & Alfano, 2018). However, one study (Pressman & Imber, 2011) found an association with bed-sharing or lacking a consistent bedtime and what was labeled faux-ADHD (i.e., transient ADHD behaviors).

Having a child’s emotional and physiological needs met during the day have been considered to lay the foundation for good sleep at night. Previously, we discussed the importance of physical needs such as a healthy diet and exercise. Of interest, the first evidence-based 24-hour guidelines for time spent in physical activity, sedentary behavior (such as playing videogames and watching TV), and sleep were recently published in Canada (Tremblay et al., 2016), underscoring the importance of daytime behaviors for sleep. Having one’s emotional needs met is also important. Emotional well-being is often operationalized as having a secure attachment with one’s parents, not having internalizing symptoms such as anxiety, not feeling lonely, and having good self-esteem. Allen et al. (2016) found moderate support for the association of emotional well-being and good sleep.

Approximately two-thirds of children with ADHD have at least one comorbid disorder, with anxiety being a frequently occurring comorbidity (Reale et al., 2017). Anxiety has been found to be associated with increased sleep problems (Becker, Pfiffner, Stein, Burns, & McBurnett, 2016). A recent meta-analysis (Harpin, Mazzone, Raynaud, Kahle, & Hodgkins, 2016) found that over the long-term, children with ADHD, especially untreated ADHD, have lower self-esteem and poorer social outcomes (e.g., poorer peer relationships). While the research is limited on attachment in children with ADHD, a review of this literature found a relationship between insecure attachment and ADHD (Storebø, Rasmussen, & Simonsen, 2016). Attachment relationships are complex with bidirectional influences. Research is pointing to the role of emotional dysregulation, both in the child with ADHD and the parent (who may also have ADHD), as a mediator of insecure attachments. The above findings would indicate that some children with ADHD may not be having their emotional needs met during the day, which could negatively impact sleep.