Sluggish Cognitive tempo; circadian preference, sleep, and daytime sleepiness

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In this podcast, we are joined by Dr. Joey Fredrick, a clinical psychology postdoctoral fellow at Cincinnati Children’s Hospital Medical Center, Ohio, USA, to tackle the question ‘Is sluggish cognitive tempo associated with circadian preference, sleep, and daytime sleepiness in adolescence?’. Joey is the first author of a paper on this topic published in the Journal of Child Psychology and Psychiatry (JCPP).

To set the scene, Joey provides us with an insight into what sluggish cognitive tempo is, before turning to his co-authored JCPP paper ‘A multi method examination of sluggish cognitive tempo in relation to adolescent sleep, daytime sleepiness, and circadian preference’ ( Joey explores what he looked at in this study, provides us with a summary, and details the methodology that he used.

With adolescence being the ‘perfect storm’ for sleep issues, Joey details how he differentiated between normal adolescent sleep patterns and those who have sluggish cognitive tempo.

Joey then shares the findings from his paper and explains what the implications of these findings are for professionals working with young people and their families.

Furthermore, Joey also comments on whether he is planning some follow-up research and provides an insight into what else is in the pipeline for him.

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Dr. Joey Frederick
Dr. Joey Fredrick

My research interests are in the areas of ADHD and co-occurring internalizing psychopathologies and problems, such as depression, social anxiety, sluggish cognitive tempo (SCT), and peer difficulties. I am also interested in identifying mechanisms that explain how family and peer factors impact internalizing problems. (Bio and Image from ResearchGate)


Jo Carlowe: Hello. Welcome to the In Conversation podcast series for the Association for Child and Adolescent Mental Health, or ACAMH, for short. I’m Jo Carlowe, a freelance journalist with a specialism in psychology. Today, I’m interviewing Dr. Joey Fredrick, a clinical psychology postdoctoral fellow at Cincinnati Children’s Hospital Medical Center, Ohio, USA.

Is sluggish cognitive tempo associated with circadian preference, sleep, and daytime sleepiness in adolescence? We’ll tackle this question in today’s podcast. Joey is the first author of a paper on this topic published in the Journal of Child Psychology and Psychiatry. The JCPP is one of the three journals produced by the Association for Child and Adolescent Mental Health. ACAMH also produces JCPP Advances and the CAMH.

If you’re a fan of our In Conversation series, please subscribe in your preferred streaming platform. Let us know how we did with a rating or review, and do share with friends and colleagues. Joey, thank you for joining me. Welcome. Can you start with a brief introduction on who you are and what you do?

Dr. Joey Fredrick: First, thanks for having me. I’m really excited to talk about my research in sluggish cognitive tempo. And so I’m a postdoctoral research fellow in the Center for ADHD at Cincinnati Children’s Hospital Medical Center in Cincinnati, Ohio. I earned my PhD in Clinical Psychology from Miami University in Oxford, Ohio. And currently, my day-to-day as a postdoctoral fellow includes assisting with grant-funded research studies that are focused on ADHD and sluggish cognitive tempo, administering diagnostic interviews for families and children, and then also leading and collaborating on papers, submitting manuscripts, and then mentoring some of our trainees and research coordinators on independent projects and learning some of our interviews.

Jo Carlowe: Brilliant. Thank you. Joey, your research that we’re focusing on today focuses on sluggish cognitive tempo, SCT. What is sluggish cognitive tempo?

Dr. Joey Fredrick: An excellent question. I’m always excited to talk about sluggish cognitive tempo. Now, SCT is a set of behaviours that are characterized by excessive mind wandering or getting lost in one’s thoughts, daydreaming, mental fogginess or confusion, drowsiness, lethargy or tiredness. And the SCT research was initially focused on studies that were looking at the structure of ADHD. And so when we think about ADHD, there’s two primary symptom dimensions.

So the first is the inattentive symptoms– so the difficulties focusing, being easily distracted, being disorganized. And the hyperactive impulsive symptoms– these are behaviours related to difficulties sitting still, blurting out, having a hard time controlling impulses. Really, the early wave of research on SCT suggested that SCT might represent a pure or restrictive inattentive profile without the features of hyperactivity impulsivity. But research said data suggested that this is not the case. And in 2016, a meta-analysis was published of studies of over 19,000 participants across childhood, adolescence, and adulthood that found that 13 items or symptoms of SCT were distinct from the inattentive symptoms– which suggested that SCT and ADHD in attention are not overlapping or redundant constructs. That SCT is, in fact, separate. And more importantly, research has also shown that SCT is associated with a host of outcomes that impact the daily functioning of children and adolescents. So specifically, we know that SCT is associated with increases in depression, anxiety, peer withdrawal or isolation from peers, or shyness. And then also academic difficulties– above and beyond the symptoms of ADHD.

So there’s a unique piece of SCT that contributes to these impairments in children and adolescents. And we think about the relation between SCT and ADHD is somewhat similar to depression and anxiety, where we know depression, anxiety, they’re related. They overlap. But they’re also distinct. And that’s pretty similar to how our thinking is when it comes to SCT and ADHD.

Jo Carlowe: Fantastic. That’s really clear. Thank you. Joey, let’s turn to your paper, “A multi method examination of sluggish cognitive tempo in relation to adolescent sleep, daytime sleepiness, and circadian preference,” recently published in the JCPP. What did you look at in this study? Can you give us a summary?

Dr. Joey Fredrick: Sure. So our paper was really guided by four limitations in the literature on SCT. First, most of the studies to date have really focused on trying to establish the internal validity of SCT, so just like we talked about with the meta-analysis. Studies looking at, are the symptoms of SCT, are they distinct from ADHD, or are they overlapping with ADHD? And then of the studies looking at the correlates or the outcomes of SCT have really focused on domains of depression, anxiety, peer difficulties, and academic difficulties, where far fewer have looked at sleep– which is surprising when we think about the behaviours, the symptoms, that we think compose of SCT, such as drowsiness, lethargy, tiredness. We would assume that there might be a link between SCT and sleep.

In addition, there’s only three studies in the SCT and sleep literature that have looked at adolescents and how SCT is associated with sleep in this period– which is also surprising, as we know that adolescence is a developmental period that’s often been characterized as the perfect storm when it comes to sleep problems. We know there’s natural, biological shifts that adolescents undergo and, later, preference for falling asleep later, going to bed later. And then there’s expectations for early waking when it comes to early school start times. We thought that adolescence was an ideal period to look at SCT and sleep. And of the studies that have looked at sleep, they’ve been fairly limited in terms of looking at daytime sleepiness or sleep duration, where we know that there’s a number of other variables and domains of sleep, such as sleep onset latency– so how long it takes an individual to fall asleep, their bedtime, their wake time. Then also what is their preference? Their what we call their circadian preference. When do they prefer to go to bed, or what’s their optimal time for falling asleep and their performance for daytime activities? So those were the three primary limitations. And then finally, also looking at more of a comprehensive test of SCT and sleep.

So when we think about how do we measure sleep problems, most of the studies within the SCT literature– and, really, the broader child and adolescent mental health literature– have looked at rating scales, so asking the adolescent, or from the parents’ perspective. Are they having any difficulties falling asleep? We really wanted to look at, though, a comprehensive test of SCT and sleep by including other objective methodologies to really capture sleep and circadian preference.

Jo Carlowe: Can you say some more about the methodology that you’ve used in the research?

Dr. Joey Fredrick: Yeah. Our study included around 300 adolescents with or without ADHD. And so this was part of a larger longitudinal study that’s conducted at in our Center for ADHD, then also at Virginia Commonwealth University, that are following adolescents with and without ADHD across time. And for our methodology we included symptom ratings of SCT through self-report measures, daytime sleepiness. We incorporated adolescents’ perspective, parents’ perspective on rating scales. Circadian preference was a self-report scale. So these are questions that ask the adolescent, if there were no expectations for getting up in the morning, what would be your preference for falling asleep? When do you feel sleepy? And then we looked at a combination of rating scales, daily diary, and actigraphy data of sleep. And this was really one of the exciting components of this study, I believe, where for two weeks we had adolescents use daily sleep diaries each morning where they reported on the previous night bedtime, how long it took them to fall asleep, how many hours they got of sleep, what time they woke up, if they had any night wakings, how long they were awake.

In addition, we looked at actigraphy data. So adolescents wore these actigraphs which were able to measure their sleep onset and sleep offset, how long they were in bed for, and then also their sleep efficiency. So we were really able to capture a lot of different elements of sleep using these rating scales, daily sleep diaries, and then also actigraphs in a sample of adolescents without, but also with, ADHD. And so because we know that kids with ADHD have higher rates of sleeping difficulties and daytime sleepiness, so we were also interested in do these effects differ in an already at-risk population for sleep problems.

Jo Carlowe: Can I check– how did you differentiate between normal adolescent sleep patterns and those who have sluggish cognitive tempo? Because as you described earlier, adolescence is the perfect storm, you’ve called it, for sleep issues. And we know late sleep onset is common in teenagers across the board.

Dr. Joey Fredrick: Yes. That’s a fantastic question and, I think, first speaks to, like you mentioned, the importance of conducting this study in adolescents that already have a tendency to have later sleep onset and going to bed later. When we think about how do we differentiate this typical sleep onset or sleep with sluggish cognitive tempo, where we do have some studies that show that sleep problems and SCT– we’ll talk about in this study, that there are effects– and so these domains are associated, but they’re also distinct. And so there’s been some studies that shown, for example, that daytime sleepiness is distinct from sluggish cognitive tempo, which suggests that, yes, maybe sleep is a component of SCT, as we’ll talk about here with some of the findings. But we also know there’s some other unique dimensions and elements when it comes to SCT. We’re really looking at, then, are there particular adolescents that might be further at risk when it comes to having elevations in SCT with these sleep difficulties.

Jo Carlowe: Let’s turn more to your findings then. What can you share from the paper?

Dr. Joey Fredrick: Our findings were fairly robust and when we think about the different domains where we found effect. So the first thing that I’ll note is that in our analyses, we controlled for a number of factors that we know are already associated with sleep problems. And so when I say controlled, that statistically we’re able to kind of remove the influence or the variance of these factors that are associated with sleep.

So just, for example, we also controlled for adolescent sex, family income, medication status. So we know that since this was a sample of kids who had diagnosed with ADHD, they were more likely to be on medication. We know that impacts sleep processes. We controlled for medication. Then we also controlled for puberty development as well based on adolescents reporting on physical characteristics that are associated with puberty development. So we were trying to really tease apart the unique effects of SCT. And we found some fairly robust findings, as I mentioned. We found that SCT was uniquely associated with increases in a later evening preference– so a preference for later sleep onset or evening activities. Also, increases in self- and parent report of daytime sleepiness. And then we also found a lot of effects using the daily diary and actigraphy data.

So we found that SCT was uniquely associated with a later sleep onset and a later bedtime, shorter sleep duration, longer time to actually fall asleep– which we call sleep onset latency– and then more night waking, and just general difficulties falling and staying asleep. What we did then was we wanted to show, do these effects remain when we incorporate ADHD symptoms? And so we found that a number of these effects remain significant above and beyond the influence of ADHD symptoms. And these effects did not differ across kids with and without ADHD, which really to us showed that the effects of SCT on these sleep difficulties might be consistent for kids who do have ADHD, but also for kids who do not have ADHD as well.

Jo Carlowe: Fascinating. Joe, what are the implications of your findings for professionals working with young people and their families?

Dr. Joey Fredrick: I think this is a fantastic question. And so as a clinician by training, and that’s really where a lot of my interest in. I’m always trying to think about how can we apply these research findings to actually clinical practice and improve the lives of families, like you mentioned. And when we think about it, I think, first, that this study I think just fits with a larger body of research that shows that SCT is really needed in routine assessment of child and adolescent mental health.

So we’ll talk about it here in a little bit. We have learned that, I think SCT is somewhat less familiar, I think just generally and with mental health professionals. And I think it’s gaining traction as our research continues to accumulate. And I think that for an adolescent that’s seen by a paediatrician or by a mental health professional that is exhibiting SCT-like behaviour. So they mind wander, they’re daydreaming. They’re having a hard time having that energy throughout the day or feeling really lethargic. I think getting a sense of their sleep patterns, and that might cue us in as to some possible difficulties related to falling asleep, staying asleep, their bedtime. Because we know that there is some evidence from some experimental studies that shorter sleep can actually cause increases in SCT behaviours. And there’s been some research that evidence-based treatments for sleep can actually improve SCT behaviour. So this really suggests that when we’re assessing and providing services to adolescents that exhibit SCT, I think getting a better sense of their sleep patterns is fairly important.

Jo Carlowe: Are adolescents offered interventions if they’re diagnosed with SCT, currently?

Dr. Joey Fredrick: This is a– I’m glad you asked– one of the things that I’m excited to share. So recently, I accepted a position in the Center for ADHD as a clinical faculty member. And one of our goals is to, over the next six to nine months, offer an SCT specialty service in our Center for ADHD at Cincinnati Children’s Hospital.

The reason we did this was we’ve learned over the years in our research and contact with families– in a qualitative study that we conducted that was published in the Journal of Attention Disorders, where we included children who were elevated in SCT and their families– we’ve learned that, as I mentioned, SCT is still pretty unfamiliar. And there are currently no evidence-based treatments that are designed to target SCT.

And so we learned from families in our conversations that families are often stuck in not knowing where to go or what to do in addition to some of our standard treatments that we administer and offer for attention problems like ADHD. So currently, there are none. But we’re really hoping that our specialty service that we’re going to offer is just one starting point where we can really start offering some tailored interventions and treatments to these families.

Jo Carlowe: Joey, what else is in the paper that you’d like to highlight?

Dr. Joey Fredrick: I think one of the main things I’d like to highlight is that if we really take a step back and we think about these different elements of sleep and how these are associated with SCT, and we imagine an adolescent who starts off with this evening preference– so they have a preference for going to bed later, they maybe have a later bedtime, they have shorter sleep then throughout the night, they have difficulties waking in the morning– thinking about the daytime impacts and how some of those impacts then might reflect these SCT behaviours, like feeling very lethargic or tired, getting lost in one’s thoughts. And I think that to me really speaks to just the cyclical process that can unravel here in relation between SCT and sleep. And so it has us thinking– and I think there’s future studies that are needed, especially with longitudinal designs– to really tease apart the direction of these associations. Shortened sleep or sleep processes causing SCT? Or is there something about SCT that is contributing to sleep difficulties? We can’t really answer that question with the design of our study and other studies to date And I think future research really teasing apart with longitudinal studies, looking at what might be these mechanisms that are linking SCT with these different elements of sleep.

Jo Carlowe: And you, personally, are you planning some follow-up research that you can share with us?

Dr. Joey Fredrick: Yes. So some of the exciting things that we have in the works. So with our data set that is a longitudinal study does offer us the unique ability to test some of these questions we have. And so we’re currently working on, first, understanding the association between SCT and daytime sleepiness over time, which will allow us to, again, answer some of these questions. Does SCT contribute to increases in sleepiness? Is sleepiness related to SCT? And we’re also really interested– and particularly I’m interested– in why SCT and sleep are associated. And one of the ways we can answer this question is through mediation studies. And so being able to look at SCT symptoms at one time point, looking at sleep problems at another time point, and being able to test the mechanisms of this relationship.

So some ideas we have is that maybe it’s possible that adolescents with SCT who have a lot of internal distractibility or internal thought processes where they’re daydreaming, maybe they’re getting lost in their thoughts, maybe that’s a mechanism where in their bed, if they’re getting lost in their own thoughts or they’re having these unrelated thoughts, that might contribute to some of these sleep difficulties. Or it’s maybe having less of this activity levels during the day, or maybe associations with internalizing symptoms that are explaining this relationship. So there’s some really exciting studies that can better test some of these questions we have so we can further our understanding of SCT and sleep.

Jo Carlowe: Joey, what else is in the pipeline for you that you’d like to mention?

Dr. Joey Fredrick: The main thing that is in the pipeline is the SCT specialty service that I just mentioned. This is a main task that we’re undertaking in partnership with Dr. Stephen Becker who’s a leading expert in the area of SCT and also sleep at the Center for ADHD. We are currently planning some of those steps to start a specialty service. And I think some things that are relevant with this paper is giving the number of studies now that have linked SCT and sleep and some recent evidence from open trials that cognitive behavioural interventions for sleep can also improve SCT behaviours. We’re starting to really brainstorm and think about maybe some sleep interventions that we might be able to offer for adolescents with SCT. And so again that’s something that we’re hoping over the next six to nine months, that we can start offering that specialty service to families. But we’re really excited about the prospect of this service that we’re going to offer at Cincinnati Children’s.

Jo Carlowe: Brilliant. And Joey, finally what is your takeaway message for those listening to our conversation?

Dr. Joey Fredrick: The main takeaway is that I think we’re at a point now in the literature that SCT continues to demonstrate relevance as a very important construct in child and adolescent mental health. We have a plethora of studies that have shown that SCT is a distinct set of symptoms that are separate from ADHD, anxiety, and depression that contribute to really many areas of impairments for adolescents, like increases in internalizing difficulties, peer problems, academic problems, and now, also sleep. We know that poor sleep is a major public health concern, that a number of adolescents do not obtain the recommended hours of sleep. They have irregular bedtimes, given some of the demands and the expectations on early waking in the morning. So I think my take home is that, even among kids with or without ADHD, there clearly appears to be a link or an association between SCT and sleep that really, I think, is going to require further intervention, assessment, and then also research.

Jo Carlowe: Joey, thank you so much. For more details on Dr. Joey Fredrick, please visit the ACAMH website,, and Twitter @acamh. ACAMH is about A-C-A-M-H. And don’t forget to follow us on your preferred streaming platform. Let us know if you enjoy the podcast with a rating or review, and do share with friends and colleagues.


Presumably sleep problems are well researched and associated difficulties, and relevant research in sleep disorders across age groups might shed some sense upon whether SCT is a specific issue, or simply an artefact of sleeping disorders. One could speculate SCt as a specific syndrome would be more believable if it did not occur with sleeping problems? This subject rather reminds me of an earlier debate between Aspergers and High Functioning Autism that did the rounds between dichotomy and unity of construct, indeed research methodologies pointed both ways for a while, before it was recognized they were one and the same population by proper longitudinal studies, I guess a framework of observation is definitely needed to clarify if SCT is explained by sleep problems or otherwise, and whether it is simply an artefact of sleep problems with I guess DIMS being the obvious sleep type of disorders, but I felt the presenter was open and honest about the limits of knowledge and I wish him well with such investigation. The obvious research is quantitative in terms of exposure and demonstrating inverse correlation between sleep ( and a measure of some aspect of that) and SCT rate. Requiring a developed objective measure of SCT against objective measures of sleep, but there lies the problem, how exactly do you define and develop objective testing for SCT? That is the starting problem that needs resolution before going into the field and doing population studies, you cannot rely on subjectivity and actually need a robust test that identifies SCT or some marker of that I presume? Otherwise you end up in tautological confounding measures that cannot elicit an answer!

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