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A team of Iranian researchers recently published a meta-analysis seeking to determine what, if any, association there may be between low vitamin D levels and ADHD in children and adolescents.
Combining the results from thirteen studies with 10,334participants, they found that youth with ADHD had "modest but significant" lower serum concentrations of 25-hydroxyvitamin D than normally developing children. The weighted mean difference was just under 7 nanograms per milliliter. The odds of obtaining such a result by chance would be less than one in a thousand(p < .001). There was little to no sign of publication bias. Between-study heterogeneity, however, was very high (I2 = 94).
These results suggest an association. But are low serum levels of vitamin D a cause or effect of ADHD? Causation is vastly more difficult to establish than an association. To begin to tease this out, the researchers identified four prospective studies that compared maternal vitamin D levels with the subsequent development of ADHD symptoms in their children. Two of these used maternal serum levels, and two used umbilical cord serum levels. Together, these studies found that low maternal vitamin D levels were associated with a 40% higher risk of ADHD in their children. Whether maternal serum or umbilical cord serum measurements were used had little or no effect on the outcome. Study heterogeneity was negligible. But the authors noted that this result "should be considered with caution" because it was heavily dependent on one of the prospective studies included in the analysis. All of which suggest a need for further prospective studies
In the meantime, the authors suggest it would be prudent to increase sun exposure and vitamin D supplementation, given the prevalence of vitamin D deficiency.

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.

What are we to make of adults who exhibit the diagnostic criteria for ADHD, but are nevertheless high-functioning and successful? A trio of British investigators has just published six case studies that explore this question.  It would have been better for them to have conducted a much larger, controlled research study but, in the absence of such data in the area, these case studies are intriguing and may help guide more informative research.
The authors recruited six successful men between the ages of30 and 65 from a National Health Service tertiary service in London. Four were in long-term relationships, with children. All had good jobs.

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In open-ended taped interviews of up to an hour in length, each was asked three questions:
1.     What do you think are the advantages and disadvantages of having ADHD?
2.     Please describe a time when you felt that your ADHD helped you to achieve something?
3.     What aspects of your ADHD would you miss if it went away?

Hyper-focus in ADHD is generally considered a deficit, inset-shifting, and task-switching. But the authors report that participants associated it with productivity. One said, "I think the energy that the ADHD brain seems to have....it's unfocused, quite scattered, chaotic and a bit random...but give that brain something that you can tune into, and it's your interest, then all that random stuff just goes boom... I get this incredible intense concentration and that's great for work."
Participants also saw advantages in divergent thinking, with one stating, "I'm an artist.... a creative type... a Bohemian.... you are most likely to be a creative person if you are a divergent thinker....and not convergent... I am very creative and that's through and through... I'm a fine art graduate, a musician, a published poet, an entrepreneur, a performer."
All the participants reported being seen as nonconformists. Depending on a viewpoint, that can be seen as either detrimental or advantageous.
Impulsivity is a core symptom of ADHD. Participants however related it to bravery, and more specifically adventurousness, spontaneity, and thrill-seeking. One said, "thrill-seeking is an ADHD thing... I can list in my life have done white water rafting, bungee jumping, hand-glider pilot ... I have done a lot in my life and achieved a lot and experienced a lot...... Furthermore, I would see a lot of that as being quite positive, and a lot of that is ADHD drive."
Another common theme was high energy and "spirit." One participant said, "I've got all this energy.... a lot of energy.... whatever it's to do with.... nature/nurture/spiritual stuff."
These testimonials are useful as a check on the usual narrative of impairment. ADHD does not predestine all it afflicts to an unfulfilling life. Many, often assisted by medication, still lead exciting, successful, rewarding lives.   Yet, we must be cautious in concluding that these individuals were successful because of their ADHD.  It is possible, even likely, that they had other strengths such as high intelligence that compensated for their ADHD symptoms.  We can not know from this report if their lives had been even more fulfilling or successful in the absence of ADHD.   See, for example, my blog about highly intelligent people with ADHD:  https://www.linkedin.com/pulse/20141126141502-65669938-smart-people-can-have-adhd-too/.
While the authors concede that "generalizing the findings of this study is not easy to do," they inexplicably "also argue that the positive aspects we found are relevant to other adults with ADHD regardless of sample size, age, gender or ethnicity."   It is not possible to draw such a definitive conclusion without a much larger sample.
On a hopeful note, they conclude, "This is a study that reaches out to people with lived experience of ADHD: service users, patients, family members, carers, partners, to say that not all symptoms of ADHD are maleficent. Recovery, high functionality, and flourishing with ADHD are possible. Too often people with lived experience hear about ADHD deficits, functional impairments, and associations with substance misuse, criminality, or other disadvantages on almost every level of life (school, work, relationships). ... This study affirms the positive human qualities, assets, and attributes in ADHD that can promote and sustain high functioning and flourishing."   I fully endorse the idea that those with ADHD can have wonderful lives, especially if they receive appropriate treatment, both medical and psychological.

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.

There has been much interest in omega-3 Polyunsaturated fatty acids (PUFAs) as treatments for ADHD. Humans are unable to synthesize the omega-3 PUFA alpha-linolenic acid (ALA)and the omega-6 PUFA linoleic acid (LA), and must therefore obtain these through food, which is why they are known as essential fatty acids.  Because cells in the brain need omega-3 PUFAs, they have been studied as a treatment for ADHD by many researchers.  Several meta-analyses are available.

A 2014 meta-analysis by Elizabeth Haw key and Joel Niggcombined nine studies involving 586 participants. It found mean blood levels of omega-3 PUFAs in persons with ADHD to be lower than in controls. The standardized mean difference (SMD) effect size was medium (SMD = .42, 95% CI = .26-.59), with less than a one in one thousand probability of such a result being obtained by chance alone. Adjusting for publication bias reduced the effect size slightly to .36 with a 95% CI of .21-.51, in the small-to-medium range. The authors then examined whether omega-3 supplementation could help alleviate ADHD symptoms. Combining 16 studies with 1,408 participants, they found improvements, but this time with a small effect size (SMD = .26, 95% CI =.15-.37), again with less than a one in a thousand probability of such a result being observed by chance. Adjusting for publication bias reduced the effect size to .16 with a 95% CI of .03-.28.  For comparison, the SMD for stimulants is about 0.9.

Another meta-analysis conducted in the same year by BasantPuri and Julian Martins combined 18 PUFA supplementation studies involving1,640 participants. They also found a small effect size for reduced ADHD symptoms (SMD = .19, 95% CI = .09-.30, p<.001). Adjusting for publication bias further reduced the effect size to a paltry and statistically insignificant level (SMD = .12, 95% CI = -.01-.25). It should be noted that while16 of the studies involved omega-3 supplementation, two involved only omega-6supplementation. Yet the results for the latter did not differ noticeably from the former. When the authors limited the analysis to the 11 studies specifically including both the omega-6GLAand the omega-3 EPA, the effect size for reducing inattention symptoms was a bit higher(SMD = .31, 95% CI = .16-.46, p<.0001). But the results were not significantly different from those for the studies without the GLA+ALA combination (.012; 95% CI: .161-.137; p=.875). Publication bias was not addressed, and the hunt for a highly specific subset with positive results may have produced a false-positive finding.  The authors conceded, "Weaknesses of this study include the following: although the pooled effect was statistically significant, only two studies showed a significant effect by themselves; the funnel plot showed evidence of publication bias; there was evidence of reporting bias; few studies were formally registered; study methodological quality was variable, and the placebo used across studies varied."

A 2016 meta-analysis by Laura Lachance et al. tried looking for differences in the ratio of omega-6 to omega-3 PUFAs, and more specifically, AA to EPA, in the blood of persons with ADHD versus normally developing persons. Pooling five studies with485 participants, it found the omega-6 to omega-3 ratio to be significantly higher in persons with ADHD, and pooling three studies with 279 participants, it likewise found the AA to EPA ratio significantly higher.

A 2017 meta-analysis by Jane Pei-Chen Chang et al. Reexamined comparative levels of omega-3 PUFAs in ADHD patients versus normally developing controls. Combining six studies with 396 participants, ADHD patients had lower levels in blood and mouth tissue, with a medium effect size (SMD =.38) that was not statistically significant (p=.14).  Omega-6 levels were indistinguishable (SMD =.03) in the two groups. AA (SMD = .18, p=.33) and EPA (SMD = .25, p=.17) levels were slightly lower, but once again statistically not significant. DHA levels were lower as well, this time with a medium effect size (SMD = .56), but at the outer margin of significance (p=.05). Only by dropping one study were the authors able to claim significance for EPA, AA, and omega-3 differences.

Chang et al. also performed a meta-analysis of supplementation studies. Combining seven studies with 534 participants, they found a small to medium reduction in ADHD symptoms with omega-3 supplementation(SMD = .38, 95% CI = .2-.56, p<.0001). Corrections for publication bias were not reported. The authors also reported large reductions in both omission errors (SMD = 1.09, 95% CI = .43-.1.75, p<.001) and commission errors (SMD =2.14, 95% CI = 1.24-3.03, p<.00001) on a neuropsychological test of attention. But the former involved only 3 studies with 214 participants, and the latter only two studies with 85 participants.

Also in 2017, Pelsser et al. published a systematic review that identified only two meta-analyses of double-blind, placebo-controlled trials of PUFA supplementation. One of those, a 2012meta-analysis by Gillies et al., found no statistically significant declines in either parent-rated ADHD symptoms (five trials, 413 participants, SMD = -.17,95% CI = -.38-.03) or teacher-rated ADHD symptoms (four trials, 324participants, SMD = .05, 95% CI = -.18-.27). The other, a 2013 meta-analysis by Sonuga-Barke et al., found only a slight and barely statistically significant reduction in symptoms (11 trials, 827 participants, SMD = .16, 95% CI =.01-.31). Pelsser et al. concluded, "Considering the small average ESs [effect sizes] PUFA supplementation is unlikely to provide a tangible contribution to ADHD treatment."

Putting all of this together, there are indications that individuals with ADHD may have lower levels of omega-3 PUFAs, and that omega-3 supplementation may slightly reduce symptoms of ADHD, but the evidence remains inconclusive, with at best small effect sizes. It is possible, but not yet demonstrated, that omega-3 PUFAs might produce good outcomes in a small subset of patients.

A Danish team recruited 29,489 participants from voluntary blood donors between the ages of 17 and 67, ensuring a large sample size. Participants were asked to complete two simple questionnaires on digital tablets. One asked two questions: "Have you ever had a migraine?" and "Have you ever had visual disturbances lasting 5-60 min followed by a headache?" A yes to either was considered positive for migraine. The other used the ADHD Self-Report Scale, with 18 ADHD symptoms evaluated on a five-point scale.

Excluding those who did not answer all questions left 26,456 participants. The risk for migraines among those with ADHD was near twice the risk for others. The (odds)'s ratio (OR) was 1.8, with a 95 percent confidence interval from 1.53 to 2.12 (p < 0.001). The OR was higher among females (2.01) than males (1.64). For those with visual disturbances, the OR was higher (1.98) than for those without (1.52). The association disappeared in those over 60, with an OR essentially equal to one(0.98, 95% CI = 0.84 - 1.15, p = 0.8).

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Although the authors concluded, "We demonstrate a significant comorbidity between migraine and ADHD in adults, and this is most prominent for participants with migraine with visual disturbances," the significance to which they refer is of the p-values, and should not be misinterpreted as an indication of a strong association, as the odds ratios point variably tweak, and weak-to-moderate associations, depending on subpopulations.  The work is, however, important as it points to another somatic comorbidity of ADHD. That list is growing and now includes obesity, eczema, and asthma.