Differences in sleep patterns, sleepiness, and physical activity levels between young adults with autism spectrum disorder and typically developing controls

Sleep problems and circadian rhythm functioning in autistic children, autism with co-occurring attention deficit hyperactivity disorder, and typically developing children: A comparative study

LAY ABSTRACT

Sleep problems are common in autism spectrum disorder (ASD) and different factors can contribute to its occurrence in this population. Misalignment of the biological clock (our circadian system) has been described as one possible explanation. While there is a body of research on sleep problems, relatively less is known about circadian functioning and the specific population of autistic children with co-occurring attention deficit hyperactivity disorder (ADHD). Using an ambulatory circadian monitoring (ACM) system, which resembles a common watch, we gathered sleep parameters and the different rhythms obtained from measuring motor activity, light exposure and distal temperature in 87 autistic children and adolescents, 27 of whom were diagnosed with co-occurring ADHD, and 30 neurotypical children and adolescents as a comparison group. Autistic children and, especially, those with co-occurring ADHD showed greater motor activity during sleep which would be worth studying in future projects which could better define this restless sleep. Of note, we observed an atypical pattern of wrist temperature, with higher values in neurotypical children, followed by autistic children and, ultimately, those with co-occurring ADHD. Temperature is one of the most valuable factors evaluated here as it is closely connected to sleep-wakefulness and the hormone melatonin. Its special pattern during day and nighttime would support the hypothesis of an atypical secretion of melatonin in autistic individuals which would also link with the higher presence of sleep problems in this neurodevelopmental condition.

Associations Between Coordination and Wearable Sensor Variables Vary by Recording Context but Not Assessment Type

Motor coordination is an important driver of development and improved coordination assessments could facilitate better screening, diagnosis, and intervention for children at risk of developmental disorders. Wearable sensors could provide data that enhance the characterization of coordination and the clinical utility of that data may vary depending on how sensor variables from different recording contexts relate to coordination. We used wearable sensors at the wrists to capture upper-limb movement in 85 children aged 6-12. Sensor variables were extracted from two recording contexts. Structured recordings occurred in the lab during a unilateral throwing task. Unstructured recordings occurred during free-living activity. The objective was to determine the influence of recording context (unstructured versus structured) and assessment type (direct vs. indirect) on the association between sensor variables and coordination. The greatest associations were between six sensor variables from the structured context and the direct measure of coordination. Worse coordination scores were associated with upper-limb movements that had higher peak magnitudes, greater variance, and less smoothness. The associations were consistent across both arms, even though the structured task was unilateral. This finding suggests that wearable sensors could be paired with a simple, structured task to yield clinically informative variables that relate to motor coordination.

Age-Related Differences in Accelerometer-Assessed Physical Activity and Sleep Parameters Among Children and Adolescents With and Without Autism Spectrum Disorder: A Meta-Analysis

Importance

Physical inactivity and sleep disorders are health-related concerns of youth with autism spectrum disorder (ASD) that can persist from childhood and exacerbate core symptoms. However, evidence on group differences in accelerometer-assessed physical activity and sleep parameters among youth with and without ASD is inconclusive and age-specific effects remain unclear.

Objective

To synthesize evidence on group differences in accelerometer-assessed physical activity and sleep parameters and examine the moderating effects of age between children and adolescents with and without ASD.

Data Sources

American Psychological Association PsychInfo, CINAHL Ultimate, ERIC, MEDLINE, SPORTDiscus with Full Text, and Web of Science from inception to February 2023.

Study Selection

Two independent reviewers screened articles for observational research comparing accelerometer-assessed physical activity levels and sleep parameters in children and adolescents with and without ASD.

Data Extraction and Synthesis

After developing a standardized form, relevant data were extracted. Quality was assessed using the McMaster Critical Review Form and rated based on sample, measurement, and analyses. The Preferring Reporting Items for Systematic Reviews and Meta-Analyses guideline was followed.

Main Outcomes and Measures

The primary outcomes were actigraphy-measured MVPA, sleep latency, sleep efficiency, total sleep time, and wake after sleep onset. Data were pooled using a random-effects model. Hedges g was used to express the effect size index. Meta-regression on age was also performed to investigate the potential moderating effects.

Results

Collectively, 1757 studies were initially identified. Among 104 articles that were assessed, 28 were included, comprising moderate-to-vigorous physical activity (MVPA), 4 sleep parameters, and 73 independent effect sizes. A total of 28 studies were included in analysis, comprising 805 children and adolescents with ASD and 1573 without ASD (age range, 5.1-16.9 years). Compared with peers without ASD, children and adolescents with ASD had a small-to-moderate difference in MVPA (g = -0.450; 95% CI, -0.622 to -0.277), total sleep time (g = -0.332; 95% CI, -0.574 to -0.090), sleep efficiency (g = -0.424; 95% CI, -0.645 to -0.203), and a moderate difference in sleep latency (g = 0.514; 95% CI, 0.351 to 0.677) measured by actigraphy. Children and adolescents with ASD experienced an age-related decline in moderate-to-vigorous physical activity (β = -0.049 [95% CI, -0.097 to -0.001]; P = .045), indicating that younger children with ASD showed a smaller difference in MVPA compared with their peers without ASD. Moderating effects of age on sleep parameters were not significant.

Conclusions and Relevance

The findings of this meta-analysis suggested that children and adolescents with ASD had lower MVPA and worse sleep than peers without ASD, and the difference in MVPA varied with age. These findings reinforce the need for public health initiatives aimed at reducing these group disparities.

Aging on the Autism Spectrum: Physical Activity in Individuals Receiving State Services in the United States

This study explores factors associated with participation in moderate physical activity and muscle strengthening activity in adults with autism receiving state services (age: 18-78 years). Researchers analyzed the National Core Indicators-In Person Survey (2017-2018) data using multilevel mixed effects logistic regression. Older adults on the autism spectrum engaged in both moderate physical activity and muscle strengthening activity less often than younger adults on the autism spectrum (OR 0.99; p < 0.05; OR 0.98; p < 0.001). Individuals reportedly in fair/poor health had 50% lower odds of engaging in moderate physical activity and 30% lower odds of engaging in muscle strengthening compared to those in good/ excellent health (OR 0.50; p < 0.001; OR 0.70; p < 0.001). Moderate physical activity/muscle strengthening initiatives may help foster this group's healthy aging.

Feasibility of Actigraphy for Evaluating Sleep and Daytime Physical Activity in Children with Autism Spectrum Disorder

This research evaluated the feasibility of actigraphy to measure sleep and physical activity in children (ages 2-8 years) with autism spectrum disorder (ASD). We also explored associations between sleep and physical activity. Validated screening measures established eligibility. Questionnaires, diaries, and 5 days and 5 nights of actigraphy monitoring were used to collect data. Of the 32 children enrolled, 27 (84.4%) completed actigraphy monitoring. Based on the median steps per day, children with high physical activity had lower total sleep time and more disruptive behaviors than children with low physical activity. Findings support the feasibility of using actigraphy to measure sleep and physical activity in children with ASD. Larger studies are needed to evaluate interactions of physical activity on sleep in this population.

A Practice Pathway for the Treatment of Night Wakings in Children with Autism Spectrum Disorder

Children with autism spectrum disorder (ASD) report high rates of sleep problems. In 2012, the Autism Treatment Network/ Autism Intervention Research Network on Physical Health (ATN/AIR-P) Sleep Committee developed a pathway to address these concerns. Since its publication, ATN/AIR-P clinicians and parents have identified night wakings as a refractory problem unaddressed by the pathway. We reviewed the existing literature and identified 76 scholarly articles that provided data on night waking in children with ASD. Based on the available literature, we propose an updated practice pathway to identify and treat night wakings in children with ASD.

Response to Melatonin Treatment in Children With Autism spectrum Disorder and Relationship to Sleep Parameters and Melatonin Levels

Melatonin is one of the most used pharmacologic treatments for sleep problems in autism spectrum disorder, though its relationship with circadian and sleep parameters is still not well stablished. A naturalistic study was conducted in children with autism spectrum disorder, previously drug-naïve, before and after treatment with immediate-release melatonin. Circadian rhythms and sleep parameters were studied using an ambulatory circadian-monitoring device, and saliva samples were collected enabling determination of dim light melatonin onset. Twenty-six children with autism spectrum disorder (age 10.50  ±  2.91) were included. Immediate-release melatonin modified circadian rhythm as indicated by wrist skin temperature, showing an increase at night. A positive correlation was found between time of peak melatonin and sleep efficiency improvement values. Sleep-onset latency and efficiency improved with immediate-release melatonin. Immediate-release melatonin could be an effective treatment to improve sleep onset and restore a typical pattern of wrist temperature, which appears to be lost in autism spectrum disorder.

Accelerometer-measured physical activity, sedentary behavior, and sleep in children with cerebral palsy and their adherence to the 24-hour activity guidelines

AIM

To measure and describe the 24-hour activities (i.e. physical activity, sedentary behavior, and sleep) and to examine adherence to the 24-hour activity guidelines among children with cerebral palsy (CP) using actigraphy.

METHOD

Children's 24-hour activities were recorded over 7 days using hip- and wrist-worn ActiGraph wGT3X-BT accelerometers.

RESULTS

In total, 362 days and 340 nights from 54 children with CP (Gross Motor Function Classification System [GMFCS] levels I-III; 44% females; median age [range] 6 years 6 months [3-12 years]) were included. Mean (SD) daily wear time was 746.2 (48.9) minutes, of which children spent on average 33.8% in light physical activity (251.6 [58.7] minutes per day), 5.2% in moderate-to-vigorous physical activity (38.5 [20.1] minutes per day), and the remaining 61.1% being sedentary (456.1 [80.4] minutes per day). Physical activity decreased while sedentary behavior increased with increasing GMFCS level. In total, 13% of all children met the physical activity recommendations, and 35% met the age-appropriate sleep duration recommendation. The proportion of children meeting the combined 24-hour guidelines for physical activity and sleep was low (5.9%), especially in those classified in GMFCS level III (0%).

INTERPRETATION

The observed low 24-hour guideline adherence rates emphasize the importance of considering the entire continuum of movement behaviors in the care of children with CP, in efforts to promote healthy lifestyle behaviors and prevent negative health outcomes.

Dynamic balance improvement in children with Autism Spectrum Disorder after an extracurricular Service-Learning Physical Education program

This study aimed to examine the acute changes in dynamic balance Postural Control experienced by children with Autism Spectrum Disorder (ASD) who undertook a 6-month extracurricular Service-Learning Physical Education (PE) program. The study used a quasi-experimental design with 23 participants divided into an experimental group and a control group. Limits of Stability protocol was used to measure the children's postural control. The results showed that the experimental group achieved statistically significant improvements. To conclude, this study provides substantial input about how extracurricular PE activities aimed at developing the general motor proficiency of ASD children can improve their dynamic balance.

A Feasibility Study of Bilateral Wrist Sensors for Measuring Motor Traits in Children With Autism

Direct, quantitative measures of hyperactivity and motor coordination, two motor characteristics associated with impairment in autism, are limited. Wearable sensors can objectively index real-world movement variables that may relate to these behaviors. Here, we explored the feasibility of bilateral wrist accelerometers for measuring upper limb activity in 3-10-year-olds with autism (n = 22; 19 boys, 3 girls; M age = 5.64, SD = 2.73 years) and without autism (n = 26; 15 boys, 11 girls; M age = 6.26, SD = 2.47 years). We investigated the relationships between movement characteristics related to duration, intensity, complexity, and symmetry on the one hand and parent-reported hyperactivity and motor coordination on the other. Participants with and without autism wore the sensors for 12-hour periods. Sensor variables varied by age but not sex, with movement intensity and complexity moderately related to motor coordination. These findings lend preliminary support to wearable sensors as a means of providing ecologically-valid metrics of motor characteristics that impact adaptive function in children with autism.

Identifying the most proximal multi-level factors associated with meeting each of the 24-h movement behavior recommendations in a sample of autistic adults

BACKGROUND

Autistic adults have poorer 24-h movement behaviors, including lower levels of physical activity, more time spent being sedentary, and shorter sleep duration than neurotypical adults. Social ecological frameworks posit that 24-h movement behaviors are determined by multi-level domains; however, not known is which multi-level factors are most important to meeting each of the 24-h movement behavior guidelines among autistic adults.

OBJECTIVE

This study examined the relative importance of a range of multi-level determinants on meeting guidelines for the 24-h movement behaviors of aerobic physical activity, sedentary behavior, and sleep.

METHODS

We administered at cross-sectional electronic survey to a national self-selecting, convenience sample of autistic adults and caregivers of autistic adults residing in the USA. We used machine learning to examine the relative variable importance (VIMP) of 55 multi-level variables with meeting recommendations for physical activity, sedentary behavior, and sleep duration. VIMPs >0 indicate predictive variables/domains.

RESULTS

A greater number of group activities attended in the last 3-months, and greater independence in completing activities of daily living were most important to meeting aerobic physical activity guidelines. Group activity participation and marital status were important to meeting sedentary behavior guidelines while having a fewer number of comorbidities was most important to achieving adequate sleep.

CONCLUSIONS

These data support hypotheses about the role of family and social level interventions targeting movement behaviors in autistic adults.

Physical activity, Sedentary Behaviour and Their Correlates in Adults with Autism Spectrum Disorder: a Systematic Review

The aim of this systematic review was to investigate what is currently known about autistic adults’ participation in physical activity and sedentary behaviour and explore any associated correlates of these behaviours. The databases EMBASE, MEDLINE, PsycINFO, PubMed, and SPORTDiscus were searched for relevant literature. The review was registered with PROSPERO (No. 189187). The search identified 2834 papers, with 12 meeting the criteria for inclusion. Correlates of physical activity and/or sedentary behaviour were reported in eight included studies. The limited evidence identified suggest that autistic adults are unlikely to meet Australia’s physical activity guidelines. Future research should use device-derived measurement to more accurately quantify activity levels within the autistic adult population.

Mutations in trpγ, the homologue of TRPC6 autism candidate gene, causes autism-like behavioral deficits in Drosophila

Autism Spectrum Disorder (ASD) is characterized by impaired social communication, restricted interests, and repetitive and stereotyped behaviors. The TRPC6 (transient receptor potential channel 6) represents an ASD candidate gene under an oligogenic/multifactorial model based on the initial description and cellular characterization of an individual with ASD bearing a de novo heterozygous mutation disrupting TRPC6, together with the enrichment of disruptive TRPC6 variants in ASD cases as compared to controls. Here, we perform a clinical re-evaluation of the initial non-verbal patient, and also present eight newly reported individuals ascertained for ASD and bearing predicted loss-of-function mutations in TRPC6. In order to understand the consequences of mutations in TRPC6 on nervous system function, we used the fruit fly, Drosophila melanogaster, to show that null mutations in transient receptor gamma (trpγ; the fly gene most similar to TRPC6), cause a number of behavioral defects that mirror features seen in ASD patients, including deficits in social interactions (based on courtship behavior), impaired sleep homeostasis (without affecting the circadian control of sleep), hyperactivity in both young and old flies, and defects in learning and memory. Some defects, most notably in sleep, differed in severity between males and females and became normal with age. Interestingly, hyperforin, a TRPC6 agonist and the primary active component of the St. John's wort antidepressant, attenuated many of the deficits expressed by trpγ mutant flies. In summary, our results provide further evidence that the TRPC6 gene is a risk factor for ASD. In addition, they show that the behavioral defects caused by mutations in TRPC6 can be modeled in Drosophila, thereby establishing a paradigm to examine the impact of mutations in other candidate genes.

Sleep Problems and Circadian Functioning in Children and Adolescents With Autism Spectrum Disorder

BACKGROUND

Sleep problems are a prevalent comorbidity in autism spectrum disorder (ASD) with a multifactorial basis in which circadian misalignment has been described.

METHODS

A cross-sectional study was conducted including 52 children and adolescents with ASD (9.85 ± 3.07) and 27 children and adolescent controls with normal intellectual functioning (8.81 ± 2.14). They were matched for age, sex, and body mass index, and all were drug-naïve. An ambulatory circadian monitoring device was used to record temperature and motor, body position, sleep, and light intensity.

RESULTS

Individuals with ASD presented longer sleep-onset latency, lower sleep efficiency, and decreased total sleep time and tended to be more sedentary and have less exposure to light. They also showed lower amplitude, low interdaily stability, and a different pattern of wrist temperature across the day, with a midpoint of sleep that did not concur with sleep midpoint indicated by the rest of circadian parameters.

CONCLUSIONS

The sleep problems observed in this sample resemble those reported previously, with the exception of nocturnal awakenings which did not show differences. The ambulatory circadian monitoring device enabled measurement of circadian parameters such as temperature which, until now, were scarcely described in children with ASD and could be used to better understand sleep and circadian system in ASD.

Brief Report: Perceived Barriers to Physical Activity Among a National Sample of Autistic Adults

Improving physical activity (PA) levels in autistic adults is an important population health goal. Limiting efforts to achieve this goal is an incomplete understanding of the barriers to PA in this high-risk group. This study utilized cross-sectional data collected via an electronic survey from 253 autistic adults aged 18-50 years to examine their perceived barriers to PA, how PA barriers differed by demographic factors, and the relationship between PA barriers and meeting PA guidelines. The Barriers to Physical Activity scale assessed the independent variable. Lack of motivation to exercise, perceiving exercise as boring, and lack of transportation were the most strongly endorsed barriers to PA. Participants who reported these barriers were significantly less likely (≤ 50%) to meet PA guidelines.

24-h movement behaviors among autistic adults: Differences by sex, age, and level of independence

BACKGROUND

Autistic adults have low levels of physical activity [PA], high levels of sedentary behavior [SB], and insufficient sleep. Not known is the extent to which engagement in these movement behaviors vary by sex, age, and level of independence in activities of daily living (ADLs).

OBJECTIVE

To characterize movement behaviors in a national sample of autistic adults by sex, age, and level of independence in ADLs.

METHODS

A national sample of autistic adults and caregivers of autistic adults self-reported PA, SB and sleep behaviors as well as demographic variables using an electronic survey. Levels of engagement in movement behaviors were described, and compared by sex, age (young-adult versus middle-age), and level of independence in ADLs.

RESULTS

Data were collected on 361 autistic adults (60.3% male, n = 217, mage = 30.82 years, SD = 10.24). Overall, 44% did not meet the PA guideline; PA guideline adherence was lowest among males and those who were dependent on others in ADLs. Overall, the SB guideline was not met by 43% of the sample at weekdays and 48% at weekends. SB guideline adherence was lowest among adults who were middle-aged, and those who were fully independent in ADLs. Overall, 35.2% did not meet the total sleep time (TST) guideline. Middle-aged autistic adults had the lowest adherence to the TST guideline.

CONCLUSIONS

These finding should prompt researchers to consider these demographic differences, and tailor research and programmatic efforts to account for the unique movement behavior profiles of different segments of this heterogenous population.

Effect of Daily Physical Activity on Sleep Characteristics in Children with Autism Spectrum Disorder

Background. Sleep problems have been reported in children with autism spectrum disorder (ASD). One of the methods proposed to improve sleep characteristics is based on physical activity (PA). Objective. To assess characteristics of sleep and the effect of PA level on sleep quality in children with ASD compared to controls. Methods. Fifty boys with ASD (ASD; 10.8 ± 2.6 years) and 18 controls (CONT, 10.1 ± 2.2 years) wore an accelerometer device for five consecutive days to obtain measures of activity and sleep characteristics. Results. Some significant differences were reported between ASD and CONT groups. Wake-up time resistance was significantly higher (p < 0.05) in ASD. Total time for PA, and daily steps number were significantly lower in the ASD group (p < 0.05). Time for sedentary behavior was significantly higher (p < 0.01) in the ASD group. Using a principal component analysis and an agglomerative hierarchical analysis, we observed three clusters. Two showed the same poor-quality indices of sleep but two opposing profiles of PA, either an insufficient PA volume (cluster 1, Total time PA = 75.1 min; Daily steps: 7704) or an important PA volume (cluster 3, Total time PA = 222.1 min; Daily steps: 17,164). Cluster 2 was characterized by moderate participation in PA and children with the best sleep indices (Total time PA = 166.8 min; Daily steps: 12,718). Conclusion. The dose–response effect of exercise on sleep may indicate large individual differences but the present findings are important to prevent sedentary behaviors or to correct over-activity that could be detrimental to the sleep quality in children with ASD.

"Just Invite Us": Autistic Adults' Recommendations for Developing More Accessible Physical Activity Opportunities

Background

Autistic adults engage in lower levels of physical activity (PA) than their nonautistic peers, and over 60% do not meet national guidelines for PA. In addition, autistic adults face myriad barriers to PA participation that can make accessing activities challenging. To support the inclusion of autistic adults in PA, this study sought to explore first-hand recommendations for PA participation from autistic adults' perspective.

Methods

We interviewed 23 autistic adults aged 18 to 75 years about their PA experiences across their lifespan, including querying the participants' recommendations for supporting autistic adults in PA. A qualitative descriptive design with a constructivist lens guided the thematic analysis.

Results

The analysis resulted in two overarching themes: (1) It's helpful to have someone there to support; and (2) It's that sensory thing, it always is. Each theme includes participant-provided recommendations to guide professionals in the field of PA.

Conclusions

The autistic adult voice, long absent from conversations about PA, is a valuable and needed addition to understand how to improve PA experiences for this population. Recommendations from this study include (1) listening to the perspectives and insight of autistic adults, (2) consideration of sensory stimulus when planning for PA participation, and (3) encouraging and providing social supports for PA participation.

Lay summary

Why was this study done?: Autistic adults have many health concerns such as anxiety, depression, and obesity. Physical activity can improve these health concerns. Yet, professionals lack knowledge about how to provide optimal physical activity experiences for autistic individuals. Very little research has engaged autistic adults to directly ask their recommendations about their own physical activity needs.What was the purpose of this study?: This study wanted recommendations from autistic adults on how to make physical activity more accessible and enjoyable. By doing this, the authors hope to increase the voices of autistic adults in physical activity research.What did the researchers do?: The researchers asked 23 autistic adults for their recommendations on how to improve physical activity experiences.What were the results of the study?: Participants' responses were grouped into two categories: (1) It's helpful to have someone there to support and (2) It's that sensory thing, it always is. The first theme highlights the social supports that many autistic adults feel they need to be successful. Supports include individuals within the close social circles of the autistic adults, such as parents, friends, and other close people. They can also include professionals, such as teachers or exercise trainers. The second theme highlights the need to address the sensory sensitivities of the individual before activity can take place; if an environment or activity is not "sensory friendly" or is not accommodating, then autistic adults are less likely to engage.What do these findings add to what was already known?: Autistic adults face many barriers to physical activity participation. These findings offer first-hand accounts by autistic adults about how to improve their physical activity experiences. These results also offer ideas on how to increase physical activity engagement for autistic individuals. Other research has focused on improving physical activity in those who are autistic, but this research is rarely from the perspective of the autistic individual. This study is one of a very small number of studies that has done this and is the first to ask autistic adults to give recommendations for physical activity participation.What are potential weaknesses in the study?: This study only interviewed autistic adults who prefer to communicate verbally, and so the study sample is not representative of all autistic adults. Many participants in the sample were from the United States, and autistic adults in other countries may have different opinions about physical activity participation. Finally, the researchers may have recruited individuals with an interest in physical activity-autistic adults who are not interested or dislike physical activity may have different recommendations.How will these findings help autistic adults now or in the future?: This study will help professionals provide more appropriate physical activity experiences to autistic adults. Also, this research could help practitioners and researcher make physical activity spaces more welcoming and enjoyable for autistic adults.

Implementation of Wearable Sensing Technology for Movement: Pushing Forward into the Routine Physical Rehabilitation Care Field

While the promise of wearable sensor technology to transform physical rehabilitation has been around for a number of years, the reality is that wearable sensor technology for the measurement of human movement has remained largely confined to rehabilitation research labs with limited ventures into clinical practice. The purposes of this paper are to: (1) discuss the major barriers in clinical practice and available wearable sensing technology; (2) propose benchmarks for wearable device systems that would make it feasible to implement them in clinical practice across the world and (3) evaluate a current wearable device system against the benchmarks as an example. If we can overcome the barriers and achieve the benchmarks collectively, the field of rehabilitation will move forward towards better movement interventions that produce improved function not just in the clinic or lab, but out in peoples' homes and communities.

Sleep in autism: A biomolecular approach to aetiology and treatment

People with autism spectrum disorder (ASD) commonly experience other comorbidities. Studies indicate that between 50% and 83% of individuals with ASD have sleep problems or disorders. The most commonly reported sleep problems are: (a) insomnia symptoms including the inability to get to sleep or stay asleep; and (b) circadian rhythm sleep-wake disorders, defined as a misalignment between the timing of endogenous circadian rhythms and the external environment. The circadian system provides timing information for the sleep-wake cycle that is regulated by the interaction of an endogenous processes (circadian - Process C, and homeostatic - Process S) and synchronizing agents (neurohormones and neurotransmitters), which produce somnogenic activity. A clinical priority in ASD is understanding the cause of these sleep problems in order to improve treatment outcomes. This review approaches sleep in autism from several perspectives: Sleep-wake mechanisms and problems, and brain areas and molecules controlling sleep (e.g., GABA and melatonin) and wake maintenance (e.g., serotonin, acetylcholine and glutamate). Specifically, this review examines how altered sleep structure could be related to neurobiological alterations or genetic mutations and the implications this may have for potential pharmacological treatments in individuals with ASD.