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Autism spectrum disorder (ASD) is frequently comorbid with ADHD. Among adults with ADHD, as many as half are reported to also have ASD.

A Dutch team set out to answer two questions:

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1)    Do adults with ADHD and comorbid ASD experience less effectiveness in pharmacological treatment for ADHD than adults with only ADHD
2)    Do adults with ADHD and comorbid ASD experience different or more severe side effects of pharmacological treatment for ADHD than adults with only ADHD, as measured in side effect scores, blood pressure, heart rate, and weight?

This was a retrospective study, using well-documented medical records, of the effects of drug treatment with methylphenidate (MPH), dexamphetamine (DEX), atomoxetine (ATX), bupropion, or modafinil.

The researchers compared 60 adults with comorbid ASD and ADHD to 226 adults with only ADHD. ADHD symptoms were scored using the Conner's ADHD Rating Scale: Self Report-Short Version (CAA RS: S-S). Side effects of ADHD medication were measured using either a 13-item or 20-item checklist with 4-point scales for item response. Researchers also tracked changes in body weight, blood pressure, and heart rate.

Following treatment, ADHD symptoms among the comorbid group declined by a quarter, and among the ADHD-only group by almost a third. There was no significant difference between men and women. Controlling for age, gender, and ADHD subtype, a comorbid diagnosis of ASD also did not significantly affect ADHD symptom reduction.

Turning to side effects, in the ADHD+ASD group, there were significant increases in decreased appetite and weight loss, and decreases in agitation, anxiety, and sadness/unhappiness. In the ADHD-only group, there were significant increases in decreased appetite, weight loss, and dry mouth, and decreases in sleeping disorder, nervousness, agitation, anxiety, and sadness/unhappiness. Yet there were no significant differences between the two groups. Side effects increased and decreased similarly in both. Likewise, there were no significant differences between the groups in changes in heart rate and blood pressure. The only significant difference in medication dosage was for bupropion, which was higher in the ADHD+ASD group, though without any sign of the difference in side effects.

The authors concluded that this retrospective study "showed pharmacological treatment of adults with diagnoses of ADHD and ASD to be just as successful as the pharmacological treatment of adults with only ADHD," but cautioned that "randomized controlled trial should be conducted to evaluate the effectiveness and possible side effects of pharmacological treatment for ADHD in patients with ASD more reliably."

A Spanish team of researchers recently completed a comprehensive review of studies looking for links between compulsive video gaming (both online and offline) and a variety of psychological disorders, including anxiety, depression, social phobia, and ADHD. The focus was on behavior "of sufficient severity to result in significant impairment in personal, family, social, educational, occupational or other important areas of functioning."

The team identified 24 studies, of which eight with a combined total of 16,786 participants looked for associations with either ADHD or its hyperactivity component. Participants included children, adolescents, and adults. One large longitudinal study, with 3,034 participants, found no association. Another study with 1,095 participants found a small effect. Two more, with a combined total of 11,868 found medium effect sizes. Four studies found large associations, but their combined total number of participants, was789, comprising less than a twentieth of the combined participants.

The authors concluded, "The relationship between Internet Gaming Disorder and ADHD and hyperactivity symptoms were analyzed in eight studies. Seven of them reported full association, with four finding large, two finding small, and one reporting moderate, effect sizes. The studies comprised two case-control, five cross-sectional and one longitudinal design; they later found no association between the two variables."[1]They also emphasized that 87 percent "of the studies describe significant correlations ... with ADHD or hyperactivity symptoms."[2]

Yet they did not note that all the studies with large effect sizes were comparatively small. And while they presented funnel charts evaluating publication bias for anxiety and depression, they did not do so for ADHD, where the small studies with very large effect sizes suggest publication bias (i.e., that evidence for association is exaggerated due to the early publication of positive findings).

Leaving out these small studies, the four high-powered studies with 15,997 participants reported effect sizes ranging from none to medium. Overall, that suggests that there is an association between ADHD and video gaming, though not a particularly strong one.  Moreover, due to the nature of the study designs, this work cannot conclude that the small effect observed is due to playing video games being a risk factor for ADHD or to the possibility that ADHD youth are more attracted to video games than others.

A German team recruited 104 adults with ADHD at both inpatient and outpatient ADHD clinics, and from ADHD self-help groups. Just under two-thirds were being treated with ADHD drugs, most with methylphenidate.

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Just under a quarter reported high internalized stigma. Two in five reported high levels of alienation, meaning a sense of "not being a fully functioning, valuable member of society." Three in ten reported high levels of social withdrawal.

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On the other hand, only two participants reported high levels of stereotype endorsement, meaning personal acceptance of stereotypes associated with mental illness. And more than two-thirds reported high stigma resistance, meaning they were internally resistant to stigmatization. Thus, while most were free of significant internalized stigma, a still substantial minority were not.

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Most of the participants expected to be discriminated against and treated unfairly by employers, colleagues at work, neighbors, and teachers should they reveal that they have ADHD. Relatively few expected to be discriminated against by health professionals, family, and friends. Almost half expected discrimination if they confided to strangers they were dating.

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Over two-thirds of participants reported they had encountered public stereotypes concerning ADHD. But, on balance, they rated these at low levels of intensity. Nevertheless, among those perceiving such stereotypes, eight out of nine sensed some degree of public doubt about the validity of ADHD as a genuine ailment ("ADHD does not exist in adults"), and three out of four had at some point encountered the argument that "ADHD is invented by drug companies." More than four out of five had heard allegations that ADHD results from bad parenting, and almost three in four had heard the claim that it results from watching too much television or playing too many video games.

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These data call for more education of the public about the nature and causes of ADHD. Information reduces stigmatization, so the widespread dissemination of the facts about ADHD is warranted.

We are only beginning to explore how ADHD affects sleep in adults. A team of European researchers recently published the first meta-analysis on the subject, drawing on thirteen studies with 1,439 participants. They examined both subjective evaluations from sleep questionnaires and objective measurements from actigraphy and polysomnography. However, due to differences among the studies, only two to seven could be combined for any single topic, generally with considerably fewer participants (88 to 873).

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Several patterns emerged. Looking at results from sleep questionnaires, they found that adults with ADHD were far more likely to report general sleep problems (very large SMD effect size 1.55). Getting more specific, they were also more likely to report frequent night awakenings(medium effect size 0.56), taking longer to get to sleep (medium-to-large effect size 0.67), lower sleep quality (medium-to-large effect size 0.69), lower sleep efficiency (medium effect size 0.55), and feeling sleepy during the daytime(large effect size 0.75).

There was little to no sign of publication bias, though considerable heterogeneity on all but night awakenings and sleep quality.

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Actigraphy readings confirmed some subjective reports. On average, adults with ADHD took longer to get to sleep (large effect size 0.80) and had lower sleep efficiency (medium-to-large effect size 0.68). They also spent more time awake (small-to-medium effect size 0.40). There was little to no sign of publication bias and there was little heterogeneity among studies.

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None of the polysomnography measurements, however, found any significant differences between adults with and without ADHD. All effect sizes were small (under 0.20), and none came close to being statistically significant.

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There were four instances where measurement criteria overlapped those from actigraphy and self-reporting, with varying degrees of agreement and divergence. There was no significant difference in total sleep time, matching findings from both the questionnaires and actigraphy. On percent time spent awake, polysomnography found little to no effect size with no statistical significance, whereas actigraphy found a small-to-medium effect size that did not quite reach significance, and self-reporting came up with a medium effect size that was statistically significant. Sleep onset latency and sleep efficiency, for which questionnaires and actigraphy found medium-to-large effects, the polysomnography measurements found little to none, with no statistical significance.

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Polysomnography found no significant differences in stage 1-sleep, stage 2-sleep, slow-wave sleep, and REM sleep. Except for slow-wave sleep, there was no sign of publication bias. Heterogeneity was generally minimal.

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One problem with the extant literature is that many studies did not take medication status into account.

The authors concluded, "future studies should be conducted in medicatio- naïve samples of adults with and without ADHD matched for comorbid psychiatric disorders and other relevant demographic variables."

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In summary, these findings provide robust evidence that ADHD adults report a variety of sleep problems.  In contrast, objective demonstrations of sleep abnormalities have not been consistently demonstrated.   More work in medication-naïve samples is needed to confirm these conclusions.

A systematic review found five studies that evaluated shared care models involving children and adolescents, in which primary care providers(PCPs) collaborated with mental health care providers in treating ADHD. The 655 participants ranged in age from 5 to 17. Two of the studies were randomized.

In one, the largest, with 321 participants, care managers acted as liaisons between PCPs and psychiatrists and provided psychoeducation and skills training for families. Effect sizes on the Vanderbilt ADHD Diagnostic Teacher Rating Scale were very small, ranging from a standardized mean difference (SMDs) of 0.07 to 0.12. Improvement on the Clinical Global Impression scale was also small (SMD = 0.3)and was not significant (p = 0.4).

In the other randomized study, with 63 participants, care managers also acted as liaisons between PCPs and a psychiatric decision support panel to provide Positive Parenting Training. The SNAP-IV hyperactivity/impulsivity score showed a medium effect size (SMD = 0.7), with a medium-to-large effect size (0.7) for improvement in social skills. The score difference for SNAP-IV inattention was not statistically significant. The other three studies followed groups of individuals over time.

In one cohort with 129 participants, PSPs consulted with psychiatrists by telephone; an evaluation, where necessary, was performed within 4 weeks. As assessed by the Clinical Global Impression-Severity scale, symptoms declined from moderately severe to mild or borderline. On the Children's Global Assessment Scale, there was an improvement from problems in more than one area of functioning to just one area.

In another cohort with 116 participants, care managers acted as liaisons between pediatricians and a psychiatrist and provided education to parents. Just over a quarter of participants showed improvement of greater than one standard deviation on the Vanderbilt ADHD Diagnostic Parent Rating Scale, and just under one in seven on the Vanderbilt ADHD Diagnostic Teacher Rating Scale.

The remaining cohort had only 26 participants. It offered PCPs access to outpatient psychiatric consultations within three weeks. PCPs reported a high level of satisfaction with their improved skills in mental health care. There was no evaluation of the effect on symptoms.

With varied study designs, methodologies, and outcomes, the authors of the review could only conclude "that PCP collaboration with psychiatrists may be associated with the increased comfort level. However, the association with symptom outcome and increased capacity was variable." Given that randomized studies report only small effects, these shared care models cannot be routinely recommended.

A team of Spanish researchers has published a systematic review of 16 studies with a total of 728 participants exploring the effects of physical exercise on children and adolescents with ADHD. Fourteen studies were judged to be of high quality, and two of medium quality.

Seven studies looked at the acute effects of exercise on eight to twelve-year-old youths with ADHD. Acute means that the effects were measured immediately after periods of exercise lasting up to 30 minutes. Five studies used treadmills and two used stationary bicycles, for periods of five to 30 minutes. Three studies "showed a significant increase in the speed of reaction and precision of response after an intervention of 20-30 min, but at moderate intensity (50-75%)." Another study, however, found no improvement in mathematical problem-solving after 25 minutes using a stationary bicycle at low (40-50%) or moderate intensity (65-75%). The three others found improvements in executive functioning, planning, and organization in children after 20- to 30-minute exercise sessions.

Nine studies examined longer-term effects, following regular exercise over many weeks. One reported that twenty consecutive weekly yoga sessions improved attention. Another found that moderate to vigorous physical activity (MVPA) led to improved behavior beginning in the third week, and improved motor, emotional and attentional control, by the end of five weeks. A third study reported that eight weeks of starting the school day with 30 minutes of physical activity led to improvement in Connor's ADHD scores, oppositional scores, and response inhibition. Another study found that twelve weeks of aerobic activity led to declines in bad mood and inattention. Yet another reported that thrice-weekly 45-minute sessions of MVPA over ten weeks improved not only muscle strength and motor skills, but also attention, response inhibition, and information processing.

Two seventy-minute table tennis per week over twelve weeks improved executive functioning and planning, in addition to locomotor and object control skills.

Two studies found a significant increase in brain activity. One involved two hour-long sessions of rowing per week for eight weeks, the other three 90-minute land-based sessions per week for six weeks. Both studies measured higher activation of the right frontal and right temporal lobes in children, and lower theta/alpha ratios in male adolescents.

All 16 studies found positive effects on cognition. Five of the nine longer-term studies found positive effects on behavior. No study found any negative effects. The authors of the review concluded that physical activity "improves executive functions, increases attention, contributes to greater planning capacity and processing speed and working memory, improves the behavior of students with ADHD in the learning context, and consequently improves academic performance." Although the data are limited by a lack of appropriate controls, they suggest that, in addition to the well-known positive effects of physical activity, one may expect to see improvements in ADHD symptoms and associated features, especially for periods of sustained exercise.

An international team of researchers recently published a meta-analysis of randomized controlled trials examining the efficacy of meditation-based therapies. Thirteen randomized controlled clinical trials(RCTs) were included: seven, with 270 participants, focused on children and adolescents; the other six, with 339 participants, were on adults. Because only one of the RCTs was appropriately blinded, the results discussed below, although promising, must be considered preliminary.

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Among children and adolescents, the meta-analysis revealed a significant, medium effect size (SMD = -0.44, 95% CI -0.69 to -0.19)on ADHD symptoms for meditation therapy versus no treatment. There were virtually no heterogeneity among studies and no sign of publication bias. Improvements in inattention and hyperactivity/impulsivity had similar effect sizes. Neuropsychological measures of inhibition and attention indicated small-to-medium effect sizes but failed to achieve statistical significance, perhaps due to the small numbers of trials and participants (159 and 179, respectively).

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For adults, the significant effect size on ADHD symptoms was medium-to-large (SMD = -.66, 95% CI -1.21 to -0.11). Once again, there was little sign of publication bias. But in this case, there was great heterogeneity among the studies. Improvements in inattention and hyperactivity/impulsivity were again comparable, although they fell just short of statistical significance for the latter. Neuropsychological measures of the efficacy of medication therapy produced statistically significant medium effect sizes for inhibition (SMD = -0.54) and working memory (SMD = - 0.42), with virtually no heterogeneity or sign of publication bias.

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Although these results are promising, the authors of the meta-analysis concluded, "Despite statistically significant effects on ADHD combined core symptoms, due to paucity of RCTs, heterogeneity across studies, and lack of studies at low risk of bias, there is insufficient methodologically sound evidence to support meditation-based therapies for ADHD."

Few studies have examined the safety and tolerability of ADHD medications (stimulants and atomoxetine) extending beyond six months, and none beyond a few years. A pair of Swedish neuroscientists at Uppsala University Hospital set out to explore longer-term outcomes. They conducted a six-year prospective study of 112 adults diagnosed with ADHD who were being treated with ADHD medications (primarily MPH, but also dexamphetamine and atomoxetine).

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They found that at the end of that period, roughly half were still on medication, and half had discontinued treatment. There were no significant differences between the two groups in age, sex, ADHD severity, or comorbidity. The average ADHD score for the entire cohort declined to vary significantly, from a mean of 37 to a mean of 26, with less than one in a thousand odds of that being due to chance. There was also no sign of drug tolerance or a need to increase the dosage over time.
All 55 adults who discontinued treatment had taken MPH for at least part of the time. Eleven had also been treated with dexamphetamine(DEX) and 15 with atomoxetine (ATX). The average time on treatment was just under two years. Almost a third quit MPH because they perceived no beneficial effect. Since they were on average taking higher doses at discontinuation than initiation, that is unlikely to have been due to suboptimal dosage. Almost another third was discontinued for various adverse mental effects, including hyperactivity, elation, depressive moods, aggression, insomnia, fatigue, and lethargy. Another one in eleven quit when they lost contact with the prescribing physician. In the case of ATX, almost half quit because of what they perceived as adverse mental effects.

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Among the 57 adults who remained on medication, four out of five reported a strong beneficial effect. Only two reported minimal or no effect. Compared with the group that discontinued, the group that remained on medication was far more likely to agree with the statements, "My quality of life has improved," and "My level of functioning has improved." Yet, as the authors caution, it is possible "that the subjects' subjective ratings contained a placebo-related mechanism in those who are compliant with the medication and pursue treatment over time." The authors reported that there were no significant differences in ADHD scores or ADHD severity between the group that quit and the group that remained on medication, even though, on average, the group that quit had been off medication for four years at follow-up.

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We cannot explain why the patients who quit treatment showed similar levels of ADHD symptoms to those who continued treatment.  It is possible that some patients remit symptoms over time and do not require sustained treatment.  But we must keep in mind that there was a wide range of outcomes in both groups. Future work needs to find predictors of those who will do well after treatment withdrawal and those who do not.

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Any decision on whether to maintain a course of medication should always weigh expected gains against adverse side effects. Short of hard evidence of continuing efficacy beyond two years, adverse events gain in relative importance. With that in mind, it is worth noting that this study reports that among those who remained on MPH, many reported side effects. More than a quarter complained of decreased appetite, one in four of dry mouth, one in five of anxiousness and increased heart rate, one in six of decreased sexual desire, one in nine of depressed mood, and one in eleven of insomnia.

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This study breaks important ground in looking at the long-term effects of medication. It reaffirms findings elsewhere of the efficacy of ADHD medications. But contrary to the authors' conclusion, the data they present suggests the possibility that permanently medicating ADHD patients may not be more efficacious than discontinuation beyond a certain point, especially when balanced against adverse side effects.
But this is just one study with a relatively small sample size. This suggests a need for additional studies with larger sample sizes to pursue these questions with greater statistical reliability.

Our genes are very important for the development of mental disorders-including ADHD, where genetic factors capture up to 75% of the risk. Until now, the search for these genes had yet to deliver clear results.   In the 1990s, many of us were searching for genes that increased the risk for ADHD because we know from twin studies that ADHD had a robust genetic component.  Because I realized that solving this problem required many DNA samples from people with and without ADHD, I created the ADHD Molecular Genetics Network, funded by the US NIMH.  We later joined forces with the Psychiatric Genomics Consortium (PTC) and the Danish psych group, which had access to many samples.  
The result is a study of over 20,000 people with ADHD and 35,000 who do not suffer from it - finding twelve locations (loci) where people with a particular genetic variant have an increased risk of ADHD compared to those who do not have the variant.  The results of the study have just been published in the scientific journal Nature Genetics, https://www.nature.com/articles/s41588-018-0269-7.
These genetic discoveries provide new insights into the biology behind developing ADHD. For example, some genes have significance for how brain cells communicate with each other, while others are important for cognitive functions such as language and learning.
Our study used the genome-wide association study (GWAS)methodology because it allowed us to discover genetic loci anywhere on the genome.  The method assays DNA variants throughout the genome and determines which variants are more common among ADHDvs. control participants.  It also allowed for the discovery of loci having very small effects.  That feature was essential because prior work suggested that, except for very rare cases, ADHD risk loci would individually have small effects.
The main findings are:

A) we found 12 loci on the genome that we can be certain harbor DNA risk variants for ADHD.  None of these loci were traditional candidate genes' for ADHD, i.e., genes involved in regulating neurotransmission systems that are affected by ADHD medications.  Instead, these genes seem to be involved in the development of brain circuits.  
B) we found a significant polygenic etiology in our data, which means that there must be many loci(perhaps thousands) having variants that increase the risk for ADHD.  We will need to collect a much larger sample to find out which specific loci are involved;

We also compared the new results with those from a genetic study of continuous measures of ADHD symptoms in the general population. We found that the same genetic variants that give rise to an ADHD diagnosis also affect inattention and impulsivity in the general population.  This supports prior clinical research suggesting that, like hypertension and hypercholesteremia, ADHD is a continuous trait in the population.  These genetic data now show that the genetic susceptibility to ADHD is also a quantitative trait comprised of many, perhaps thousands, of DNA variants
The study also examined the genetic overlap with other disorders and traits in analyses that ask the questions: Do genetic risk variants for ADHD increase or decrease the likelihood a person will express other traits and disorders.   These analyses found a strong negative genetic correlation between ADHD and education. This tells us that many of the genetic variants which increase the risk for ADHD also make it more likely that a person will perform poorly in educational settings. The study also found a positive correlation between ADHD and obesity, increased BMI, and type-2 diabetes, which is to say that variants that increase the risk of ADHD also increase the risk of overweight and type-2 diabetes in the population. This work has laid the foundation for future work that will clarify how genetic risks combine with environmental risks to cause ADHD.  When the pieces of that puzzle come together, researchers will be able to improve the diagnosis and treatment of ADHD.