Associate Professor Stephen Becker This article  in Journal of Child Psychology and Psychiatry   was led by Professor Edmund Sonuga-Barke, and  it was a really nice opportunity to reflect   back on the past 50 years of research on ADHD,  attention deficit hyperactivity disorder, and   how far we’ve come, but also, that there’s so much  left that we still need to understand and learn,   to help support individuals with ADHD. And so,  that was really the goal of the article, to look   back in time to what we’ve accomplished and what  we’ve learnt, but also be very forward-looking   in terms of what the next pressing questions  are to address in the next stage of research. The section that I had the opportunity to work on  was specific to co-occurring conditions that very   frequently are part of, or coincide with,  ADHD. So, specifically the section that I   thought about a lot was emotional dysregulation,  which there’s been a lot of research interest   in in recent decades, but then, also, sleep  problems, as well as sluggish cognitive tempo,   or what we’ve more recently referred to as  cognitive disengagement syndrome, a set of   behaviours characterised by excessive daydreaming,  mental confusion or fogginess, kind of, slowed   behaviour or thinking. And research that started  in the 1980s related to sluggish cognitive tempo,   and where that’s gone, over the last several  decades, has been exciting to see [pause]. For ADHD and sleep, I think one of the established  facts is simply how prevalent sleep difficulties   are in individuals with ADHD. To the point that  actually the diagnostic manual, the DSM-III,   back in the 1980s, restless sleep was actually  one of the symptoms used to define the disorder.   That went away in DSM-IV in 1994, but sleep  has been a longstanding part of the clinical   picture for many individuals with ADHD. Whether  that’s poor quality sleep, insufficient sleep,   or taking a really long time to fall asleep,  a long sleep onset latency, as well as growing   research interest in circadian function related  to ADHD, has been a long history, as well. In terms of ADHD and sluggish cognitive tempo, for  a long time there – the prevailing question really   was, are sluggish cognitive tempo symptoms, again,  daydreaming, mental confusion, fogginess, or that   slowness or lethargy, are those really different,  empirically, from ADHD inattentive symptoms? And   a number of studies, over the course of a few  decades, started to consistently show that,   yes, they are empirically distinct. And so, then  research started to turn a little bit more to,   if these symptoms are different from ADHD, do they  relate to functioning in different ways? In terms   of, do they relate to functioning in terms of  kids’ lives, in terms of their academic or social,   emotional adjustment? And that’s largely where  the research currently is in terms of thinking   through how we measure this construct to better  assess it, so that we can understand how it   relates to functional outcomes in children  and adults with and without ADHD [pause]. Related to ADHD and sleep, one of the new  leads was a study that I had the opportunity   to lead several years ago now, where we  recruited adolescents, 13 to 17 years old,   who all were diagnosed comprehensively by  our team with ADHD. And what we did was,   we did a sleep restriction extension protocol  with these teens to really get at the question   of does shortened sleep duration – could  we see that as a causal contributor to   ADHD symptoms or associated co-occurring  conditions or impairments in teens with ADHD? And so what we did is, for three weeks during  the summer months – we did not want to negatively   impact their actual grades or their performance  during school, so we did the study during the   summer months, and the teens came in for three  weeks, three different visits on Friday mornings.   And what we did is we randomised them to which  order, that they would get either a short sleep   week, where their – if they restricted their  sleep to being in bed for about six and a half   hours a night, or an extended sleep, where  they were instructed to stay in – be in bed   for nine and a half hours at night. But their  wakeup time was consistent for all three weeks. And what we found was really compelling and pretty  convincing evidence that during the shortened   sleep week, teens not only had more significant  ADHD inattentive symptoms specifically,   but also worsened mood, more depressive  symptoms. They did also have higher sluggish   cognitive tempo symptoms, as well as impact  on their positive and negative affect. And so,   that’s really a pretty important study for  showing that shortened sleep duration might   actually not only be part of the clinical  picture with ADHD, but also be a part of   the causal contributor to ADHD symptoms,  or their severity in individuals with ADHD. A study that I’ll highlight in  terms of sluggish cognitive tempo,   that I think is a nice recent lead, is thinking  through, how does SCT symptoms predict adjustment   longitudinally? The vast majority of studies in  this area continue to be cross-sectional studies,   which are very informative, very helpful, but  certainly we need to move the field to be thinking   more developmentally and then, also be looking  at mechanisms and processes across development. And so, in one study, with some – my colleagues,  including Dr Erik Willcutt, and Len Burns,   what we were able to do is look prospectively in a  large sample of youth to show actually a different   – associations that sluggish cognitive tempo  and ADHD inattentive symptoms had with specific   academic outcomes. We found that SCT symptoms  longitudinally predicted worse reading functioning   in adolescents, whereas ADHD inattentive symptoms  predicted poor math functioning in adolescents.   So, really, we need to replicate that finding,  further test that out, but that’s a – those are   the sorts of differentials, and understanding why  those differentials and associations might exist,   I think are really novel new findings, that we’ll  need to follow-up on in future research [pause]. There are so many different avenues, both related  to sleep and sluggish cognitive tempo in the   context of ADHD. For sleep, I really do think  we need to have a much better understanding   of both sleep function, but also circadian  function, and that interplay of sleep and   circadian function in the context of either the  aetiology or the maintenance or the severity of   ADHD across the lifespan, that, to me, is really a  pressing question. In addition to really thinking   about how do we treat sleep in the context of  ADHD? Whether or not that’s through medication,   whether or not that’s through supplements,  such as melatonin, bright light therapy,   or other cognitive behavioural based sleep  interventions, I think are all really exciting   directions that would, hopefully, not only inform  our knowledge, but importantly, improve the lives   for individuals with ADHD who also experience  various sleep or circadian disruptions. And for sluggish cognitive tempo, like  I mentioned, we do need to have far more   longitudinal studies, including  studies with multiple timepoints,   to really start testing developmental  processes and mechanisms, as well as   a more robust measurement in terms of  thinking through the neurobiology and   neurophysiology that might underly sluggish  cognitive tempo in the context of ADHD.