M. Jackson Group Update – April 2016 – Recent Findings in Attention Deficit Hyperactivity Disorder (ADHD)

This month’s post is from Ken Pope’s listserv, where he kindly provides daily summaries of current articles in the field.  ADHD is an issue of great professional and personal interest to me and I appreciated this recent review of findings.  The article is as follows:
Tomorrow’s issue of *Lancet* (March 19) includes a review article: “Attention deficit hyperactivity disorder.”

PLEASE NOTE: As usual, I’ll include both the author’s email address (for requesting electronic reprints) and a link to the complete article at the end below.

The authors are Prof Anita Thapar, FRPsych, &  Miriam Cooper, MRCPsych.

Here’s an excerpt: “In the general population, the estimated prevalence of ADHD in children is 3?4% (95% CI 2?6-4?5) according to the most recent meta-analysis,9 with lower rates of around 1?4% reported for hyperkinetic disorder from European studies.10 International comparisons show that prevalence does not vary by geographical location but is affected by heterogeneity in assessment methods (eg, use of an additional informant to the parent or carer) and diagnostic conventions (eg, ICD vs DSM).11 Notably, there is a marked under-representation of studies on ADHD from low-income and middle-income countries.”

Another excerpt: “ADHD is a familial disorder. Its relative risk is about 5-9 in first-degree relatives of probands with ADHD.37 Many twin studies of ADHD from different countries have consistently yielded very high heritability estimates of about 76%, a magnitude similar to that reported for schizophrenia and autism.38”

Another excerpt: “Environmental factors are also known to be important in ADHD. Because evidence for modifiable causes can affect clinical decision making, public health priorities, and clinician and patient behaviour,49 we will discuss whether findings on individual environmental risks meet accepted standards for inferring causation.50”

Another excerpt: “Although there is no cognitive profile that defines ADHD, deficits in various neuropsychological domains have been reliably identified. In terms of executive functioning, the most consistent and strong associations are seen for response inhibition, vigilance, working memory, and planning.66 In terms of non-executive deficits, associations are seen with timing,67 storage aspects of memory,68 reaction time variability,69 and decision making.70 However, there is substantial heterogeneity in cognitive functioning even within single samples,71 and there is not a straightforward association between cognitive performance and the trajectory of clinical symptoms.72, 73 There is evidence, though, that some cognitive deficits are improved by methylphenidate, with a meta-analysis showing improvements in executive and non-executive memory, reaction time, reaction time variability, and response inhibition.74”

Another excerpt: “There are specific guidelines for the stepwise management of ADHD, such as those developed by the National Institute for Health and Care Excellence (NICE)7 and the Scottish Intercollegiate Guidelines Network (SIGN)93 in the UK, by the Eunethydis European ADHD Guidelines Group (EAGG)94 in Europe, and by the American Academy of Pediatrics (AAP)95 and the American Academy of Child and Adolescent Psychiatry (AACAP)96 in the USA. The main difference between these guidelines is that US guidance does not preclude the use of pharmacological treatment for preschool children or for those with mild ADHD; practice that is not recommended in Europe where a stepwise approach is recommended. If pharmacological treatment is prescribed, it should be in conjunction with behavioural interventions–namely, optimised classroom management strategies, parental psychoeducation, and behavioural management techniques. However, there is no one-size-fits-all solution to management. Individual circumstances such as current academic or employment demands and medical history should be taken into account, and appropriate evidence-based treatments for comorbidities should also be initiated.

Another excerpt:”The only non-pharmacological interventions that currently form a core part of treatment guidelines are behavioural interventions. Initial results from the largest trial of ADHD interventions so far, the multimodal treatment study of children with ADHD (MTA),97 suggested that the combination of intensive behavioural treatment plus pharmacological treatment did not offer additional benefit over pharmacological treatment alone for core ADHD symptoms, but that the combination might have provided some benefit in terms of associated symptoms and levels of functioning as well as the need for a lower drug dose. In a more recent series of meta-analyses investigating randomised controlled trials of non-pharmacological interventions, the investigators concluded that, along with neurofeedback, cognitive training, and restricted elimination diets, behavioural interventions cannot be recommended as interventions for core ADHD symptoms until better evidence of their effectiveness is reported by blinded assessments.98 Elimination of artificial food colouring98 might be beneficial, but to what extent and for which population of patients is unclear.99 A meta-analysis has shown that children with ADHD have lower concentrations of omega-3 fatty acids than controls and that supplementation improves ADHD symptoms to a modest degree (an effect size about a quarter as large of that seen for pharmacological treatment); but whether subnormal blood concentrations should be the indication for treatment is not understood.100 However, there is evidence from blinded randomised controlled trials of a beneficial effect of behavioural interventions on parenting and child conduct problems,101 and there is evidence that cognitive behaviour therapy may be useful for adults with ADHD when used in conjunction with pharmacological treatment.102″

Another excerpt: “Stimulants such as methylphenidate and dexamfetamine are the first-line pharmacological treatments for ADHD, and the noradrenaline reuptake inhibitor atomoxetine is the second-line treatment. Each of these treatments increases catecholamine availability. Meta-analyses have provided evidence for the efficacy of stimulants for ADHD in children,103 in children with co-occurring autism spectrum disorder,104 and in adults.105 Although it is recommended that ADHD is treated in individuals with autism spectrum disorder or intellectual disability, or both, side-effects of pharmacological treatment in these individuals are more common than in those with ADHD alone.106, 107 Meta-analyses have shown beneficial effects of atomoxetine in children108 and in adults.109 Extended-release guanfacine and extended-release clonidine are licensed for use in the USA. Atypical antipsychotics are not indicated for treatment of core ADHD symptoms.”

Here’s how the article ends: “ADHD is a very important condition because of its high prevalence, persistence into adult life, and adverse outcomes that extend beyond the affected individual. Although ADHD is still viewed with scepticism by some and often remains stigmatised by the media, the evidence for it being a clinically and biologically meaningful entity is robust and consistent across design type and sample. There are established assessment methods and good treatment evidence. However, as is true for any chronic disorder, repeated assessment is likely to be needed and treatment will typically need many adjustments over time. Impairments beyond core diagnostic criteria, developmental change, and an individual’s psychosocial strengths, weaknesses, and resources are all important aspects for consideration.”

REPRINTS: <thapar@cardiff.ac.uk>

The article is online at:

Ken Pope


“Suppose we did our work
like the snow, quietly, quietly.
leaving nothing out.”
–Wendell Berry