0983 Sleep Associated With Executive Functioning Among Adolescents Across The Adhd Continuum

Introduction

Executive functioning (EF) deficits are a key feature of ADHD, and sleep disturbances may be an important contributor. Specifically, disturbed sleep is prevalent in ADHD and similar EF deficits are observed in ADHD and sleep disorders. Associations between disrupted sleep and EF in ADHD are poorly understood, particularly during adolescence. This study is among the first to examine relationships between sleep and EF using polysomnography (PSG) among adolescents across the ADHD symptom continuum.

Methods

In this ongoing study, 42 adolescents aged 13 to 17 (mean age = 14.86, 20 females) completed 3 nights of at-home PSG recording (total sleep time; TST) and self-reports of sleep quality, daytime sleepiness, and chronotype. Seventeen had ADHD and 25 were healthy controls (HC). Participants and parents also completed a measure of EF (BRIEF-2; global and behavioral, emotional, and cognitive subscales). Linear regressions controlling for age and sex evaluated associations between sleep and EF.

Results

Self-reported poorer sleep quality and greater daytime sleepiness and eveningness tendency (p’s<.05), but not TST, were associated with poorer self-reported global EF among adolescents. Shorter TST and greater eveningness were correlated with poorer parent-reported global EF (p’s<.05). Follow up analyses examine differential relationships between sleep and behavioral, emotional, and cognitive domains of EF and between ADHD and HC groups.

Conclusion

This study is among the first to examine relationships between sleep and EF across the ADHD continuum in an adolescent-specific sample using PSG. Objectively-measured TST as well as subjective measures of sleep were associated with poorer EF in adolescents across the ADHD continuum. Prevention/intervention strategies focused on sleep may support EF among adolescents, and future studies should examine this possibility. In addition, given variability in EF among individuals with ADHD, future studies should investigate whether sleep disturbances identify a phenotypic subgroup within ADHD at risk for EF deficits.

Support

This work was supported by NIMH K23 MH108704 (Dr. Lunsford-Avery)

Associations between imprinted gene differentially methylated regions, appetitive traits and body mass index in children

BACKGROUND

Knowledge regarding genetic influences on eating behaviours is expanding; yet less is known regarding contributions of epigenetic variation to appetitive traits and body mass index (BMI) in children.

OBJECTIVE

The purpose of this study was to explore relationships between methylation at differentially methylated regions (DMRs) of imprinted genes (insulin-like growth factor 2/H19 and Delta-like, Drosophila, homolog 1/maternally expressed gene 3) using DNA extracted from umbilical cord blood leucocytes, two genetically influenced appetitive traits (food responsiveness and satiety responsiveness) and BMI.

METHODS

Data were obtained from participants (N = 317; mean age = 3.6 years; SD = 1.8 years) from the Newborn Epigenetic STudy. Conditional process models were implemented to investigate the associations between DMRs of imprinted genes and BMI, and test whether this association was mediated by appetitive traits and birthweight and moderated by sex.

RESULTS

Appetitive traits and birthweight did not mediate the relationship between methylation at DMRs. Increased insulin-like growth factor 2 DMR methylation was associated with higher satiety responsiveness. Higher satiety responsiveness was associated with lower BMI. Associations between methylation at DMRs, appetitive traits and BMI differed by sex.

CONCLUSIONS

This is one of the first studies to demonstrate associations between epigenetic variation established prior to birth with appetitive traits and BMI in children, providing support for the need to uncover genetic and epigenetic mechanisms for appetitive traits predisposing some individuals to obesity.

Maternal pre-pregnancy obesity and child neurodevelopmental outcomes: a meta-analysis

This review examined evidence of the association between maternal pre-pregnancy overweight/obesity status and child neurodevelopmental outcomes. PubMed and PsycINFO databases were systematically searched for empirical studies published before April 2017 using keywords related to prenatal obesity and children's neurodevelopment. Of 1483 identified papers, 41 were included in the systematic review, and 32 articles representing 36 cohorts were included in the meta-analysis. Findings indicated that compared with children of normal weight mothers, children whose mothers were overweight or obese prior to pregnancy were at increased risk for compromised neurodevelopmental outcomes (overweight: OR = 1.17, 95% CI [1.11, 1.24], I²  = 65.51; obese: OR = 1.51; 95% CI [1.35, 1.69], I²  = 79.63). Pre-pregnancy obesity increased the risk of attention deficit-hyperactivity disorder (OR = 1.62; 95% CI [1.23, 2.14], I²  = 70.15), autism spectrum disorder (OR = 1.36; 95% CI [1.08, 1.70], I²  = 60.52), developmental delay (OR = 1.58; 95% CI [1.39, 1.79], I²  = 75.77) and emotional/behavioural problems (OR = 1.42; 95% CI [1.26, 1.59], I²  = 87.74). Given the current obesity prevalence among young adults and women of childbearing age, this association between maternal obesity during pregnancy and atypical child neurodevelopment represents a potentially high public health burden.

Quantitative integration of single-subject studies: Methods and misinterpretations

Derenne and Baron (1999) criticized a quantitative literature review by Kollins, Newland, and Critchfield (1997) and raised several important issues with respect to the integration of single-subject data. In their criticism they argued that the quantitative integration of data across experiments conducted by Kollins et al. is a meta-analysis and, as such, is inappropriate. We reply that Kollins et al. offered behavior analysts a technique for integrating quantitative information in a way that draws from the strengths of behavior analysis. Although the quantitative technique is true to the original spirit of meta-analysis, it bears little resemblance to meta-analyses as currently conducted or defined and offers behavior analysts a potentially useful tool for comparing data from multiple sources. We also argue that other criticisms raised by Derenne and Baron were inaccurate or irrelevant to the original article. Our response highlights two main points: (a) There are meaningful quantitative techniques for examining single-subject data across studies without compromising the integrity of behavior analysis; and (b) the healthiest way to refute or question findings in any viable field of scientific inquiry is through empirical investigation.

Association between attention-deficit/hyperactivity disorder symptoms and obesity and hypertension in early adulthood: a population-based study

Objective

To examine associations between attention-deficit/hyperactivity disorder (ADHD) symptoms, obesity and hypertension in young adults in a large population-based cohort.

Design, Setting, and Participants

The study population consisted of 15,197 respondents from the National Longitudinal Study of Adolescent Health, a nationally representative sample of adolescents followed from 1995 – 2009 in the United States. Multinomial logistic and logistic models examined the odds of overweight, obesity, and hypertension in adulthood in relation to retrospectively reported ADHD symptoms. Latent curve modeling was used to assess the association between symptoms and naturally occurring changes in body mass index (BMI) from adolescence to adulthood.

Results

Linear association was identified between the number of inattentive (IN) and hyperactive/impulsive (HI) symptoms and waist-circumference, BMI, diastolic blood pressure, and systolic blood pressure (all ps for trend < .05). Controlling for demographic variables, physical activity, alcohol use, smoking, and depressive symptoms, those with 3 or more HI or IN symptoms had the highest odds of obesity (HI 3+ OR, 1.50; 95% CI, 1.22-2.83; IN 3+ OR, 1.21; 95% CI, 1.02-1.44) compared to those with no HI or IN symptoms. HI symptoms at the 3+ level were significantly associated with a higher OR of hypertension (HI 3+ OR, 1.24; 95% CI 1.01-1.51; HI continuous OR, 1.04; 95% CI 1.00-1.09), but associations were non-significant when models were adjusted for BMI. Latent growth modeling results indicated that compared to those reporting no HI or IN symptoms, those reporting more 3 or symptoms had higher initial levels of BMI during adolescence. Only HI symptoms were associated with change in BMI.

Conclusion

Self-reported ADHD symptoms were associated with adult BMI and change in BMI from adolescence to adulthood, providing further evidence of a link between ADHD symptoms and obesity.

SNPs in dopamine D2 receptor gene (DRD2) and norepinephrine transporter gene (NET) are associated with continuous performance task (CPT) phenotypes in ADHD children and their families

Haplotype-tagging SNP analyses were conducted to identify molecular genetic substrates of quantitative phenotypes derived from performance on a Continuous Performance Task (CPT). Three hundred sixty-four individuals were sampled from 152 families ascertained on the basis of at least one child having ADHD. Probands, their affected and unaffected siblings, and parents were administered a CPT. Four different components of performance were analyzed and tested for association with SNPs from 10 candidate genes involved in monoaminergic function. After correcting for multiple comparisons and controlling for multiple individuals from the same family, significant associations were identified between commission errors and SNPs in the DRD2 gene (rs2075654, rs1079596), and between reaction time variability and a SNP in the NET gene (rs3785155). These findings suggest that commission errors and reaction time variability are excellent candidates as ADHD endophenotypes based on previously published criteria. Results also shed light on the molecular genetic basis of specific processes that may underlie the disorder.

Assessing the abuse potential of methylphenidate in nonhuman and human subjects: a review

Methylphenidate (MPH) is widely used for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) in children, adolescents, and adults. Methylphenidate is clearly effective for the treatment of ADHD, but there is controversy as to whether it has significant abuse potential like other psychostimulants (e.g., D-amphetamine and cocaine). In general, the drug is believed to be abused at rates much lower than those for other stimulants. The present review examines studies that investigated the behavioral pharmacological profile of methylphenidate and discusses how results from these studies address its abuse liability. Using MEDLINE search terms methylphenidate, drug discrimination, reinforcement, self-administration, subjective effects, subject-rated effects, abuse potential, and abuse liability, along with a review of the references from identified articles, 60 studies were located in which the reinforcing, discriminative-stimulus, or subjective effects of methylphenidate were directly assessed in nonhumans or humans. Forty-eight (80.0%) of the studies reviewed indicate that methylphenidate either functions in a manner similar to D-amphetamine or cocaine (e.g., functions as a reinforcer, substitutes fully in drug discrimination experiments), or produces a pattern of subjective effects suggestive of abuse potential. The results are discussed as they pertain to factors that may account for the apparent discrepancy in abuse rates between methylphenidate and other stimulants, including characterization of actual abuse rates, defining abuse and misuse, pharmacokinetic factors, and validity of abuse liability assays.

Temporal discounting: basic research and the analysis of socially important behavior

Recent basic research on human temporal discounting is reviewed to illustrate procedures, summarize key findings, and draw parallels with both nonhuman animal research and conceptual writings on self-control. Lessons derived from this research are then applied to the challenge of analyzing socially important behaviors such as drug abuse, eating and exercise, and impulsiveness associated with attention deficit hyperactivity disorder. Attending to the broader temporal context in which behavior occurs may aid in the analysis of socially important behavior. Applying this perspective to the study of behavior in natural environments also highlights the importance of combining methodological flexibility with conceptual rigor to promote the extension of applied behavior analysis to a broader array of socially important behaviors.

Effects of methylphenidate on sensitivity to reinforcement in children diagnosed with attention deficit hyperactivity disorder: an application of the matching law

The behavior of children diagnosed with attention deficit hyperactivity disorder (ADHD) has been hypothesized to be the result of decreased sensitivity to consequences compared to typical children. The present study examined sensitivity to reinforcement in 2 boys diagnosed with ADHD using the matching law to provide more precise and quantitative measurement of this construct. This experiment also evaluated the effects of methylphenidate (MPH) on sensitivity to reinforcement of children with ADHD. Subjects completed math problems to earn tokens under four different variable-interval (VI) schedules of reinforcement presented in random order under both medicated and nonmedicated conditions. Results showed that, in the medicated condition, the matching functions for both subjects resulted in higher asymptotic values, indicating an overall elevation of behavior rate under these conditions. The variance accounted for by the matching law was also higher under the medicated conditions, suggesting that their behavior more closely tracked the changing rates of reinforcement while taking MPH compared to placebo. Under medicated conditions, the reinforcing efficacy of response-contingent tokens decreased. Results are discussed with respect to quantifying behavioral changes and the extent to which the drug interacts with prevailing contingencies (i.e., schedule values) to influence behavioral variability.

Effects of training dose on the relationship between discriminative-stimulus and self-reported drug effects of d-amphetamine in humans

The aim of the present experiment was to examine the relationship between the discriminative-stimulus and self-reported effects of drugs in humans. To accomplish this aim, nine healthy adult volunteers (four females, five males) were trained to discriminate between placebo and 10 mg d-amphetamine (low-dose group) or 20 mg d-amphetamine (high-dose group). After acquiring the placebo-amphetamine discrimination, a range of doses of d-amphetamine (1.25-20 mg) was tested to determine if they shared discriminative stimulus effects with the training dose. Participants in the low-dose group exhibited a significant leftward shift in the dose-response function for discrimination performance, which is concordant with previous preclinical and human drug discrimination studies that assessed the effects of training dose. Consistent with the drug discrimination findings, participants in the low-dose group exhibited a significant leftward shift in the dose-response function for several self-reported drug effects (e.g., Like the Drug and Stimulated). However, several other self-reported drug effect items were not significantly influenced by training condition (e.g., Anxious/Nervous and Bad Effects). These results suggest that the discriminative-stimulus and self-reported drug effects of d-amphetamine overlap, but are not isomorphic. Furthermore, these results illustrate that behavioral history significantly influences subsequent drug effects in humans.

Factors affecting the reliability of clinical judgments about the function of children's school-refusal behavior

Conducted two studies to examine the interrater reliability, test-retest stability, and the effect of various clinician variables, such as years of clinical experience, theoretical orientation, and prior experience with children, on clinical judgments about the reinforcement functions of children's school-refusal behavior. Results indicated that the judgments by individual clinicians were of questionable reliability. Judgments aggregated across 3 clinicians yielded acceptable interrater and test-retest reliability in Study 1, but a greater number of clinicians were necessary to achieve acceptable reliability in Study 2. Years of clinical experience and training were the only clinician variables related to the reliability of judgments about reinforcement functions. Several recommendations for the clinical assessment of the function of children's school-refusal behavior are discussed.

Comparison of acute behavioral effects of sustained-release and immediate-release methylphenidate

The rate of onset of a drug's effect is an important determinant of its abuse potential. This experiment examined the acute behavioral effects of orally administered sustained-release methylphenidate (SR; 20-40 mg), immediate-release methylphenidate (IR; 20-40 mg), and placebo in 10 healthy volunteers. Drug effects were assessed before drug administration and periodically afterwards for 6 hr using drug-effect questionnaires and performance measures that are sensitive to the acute effects of stimulants. The IR formulation produced stimulant-like drug effects (e.g., increased ratings of "good effects") that generally varied as a function of dose and time. The SR formulation produced only transient effects on these measures. These findings are consistent with previous research on the influence of rate of onset using other drugs and suggest that the abuse potential of IR methylphenidate may be greater than that of SR methylphenidate.

Discriminative-stimulus and participant-rated effects of methylphenidate, bupropion, and triazolam in d-amphetamine-trained humans

The discriminative-stimulus and participate-rated effects of a range of doses of d-amphetamine (2.5-20 mg), methylphenidate (5-40 mg), bupropion (50-400 mg), and triazolam (0.0625-0.5 mg) were tested in 5 humans trained to discriminate between oral d-amphetamine (20 mg) and placebo. d-Amphetamine and methylphenidate generally dose dependently increased drug-appropriate responding. Bupropion and triazolam on average occasioned less than or equal to 40% drug-appropriate responding. d-Amphetamine, methylphenidate, and bupropion produced stimulant-like participant-rated effects, while triazolam produced sedative-like effects. These results further demonstrate that the acute behavioral effects of d-amphetamine and methylphenidate overlap extensively in humans, which is concordant with preclinical studies. Bupropion produced some d-amphetamine-like, participant-rated drug effects but did not occasion significant levels of d-amphetamine-appropriate responding. These findings are concordant with previous findings of a dissociation between the discriminative-stimulus and participant-rated effects of drugs.