Sluggish Cognitive Tempo (SCT): Not just for "Predominantly Inattentives" Anymore?!

[namazu]

Two recently-published studies suggest SCT is a separate disorder from ADHD, but co-occurs about 50% of the time -- and in both ADHD-PI and ADHD-C.

This could be filed under "scientific discussions", but I thought it would be of interest to a wider audience, so I put it here.

There's been a lot of talk recently about "sluggish cognitive tempo" or "SCT".

Unlike ADHD, SCT is not a formal diagnosis existing in the DSM-IV.

Rather, it's a collection of symptoms that have often been noticed by clinicians and researchers, often in people who are referred for ADHD evaluations or diagnosed with ADHD.

Symptoms of "SCT", as it is currently conceived, include things like "daydreamy", "processes information slowly", and "lethargic/hypoactive". There's not really a standard definition at the moment.

Some researchers (notably Russell Barkley) have argued that people diagnosed with the "Predominantly Inattentive" subtype of ADHD (ADHD-PI), who lack hyperactive-impulsive symptoms altogether, may really represent a separate group who would be better described by the SCT label than the ADHD label. Others have argued that ADHD really encompasses SCT.

In recent months, there have been a couple of eye-opening studies on SCT, and I wanted to summarize them for y'all.

Study #1:
Skirbekk B, Hansen BH, Oerbeck B, and Kristensen H. The relationship between sluggish cognitive tempo, subtypes of attention-deficit/hyperactivity disorder, and anxiety disorders. Journal of Abnormal Child Psychology 39(4):513-525. May 2011.

What they did:
The authors, working in Norway, identified kids ages 7-13 who were being seen in outpatient clinics for evaluation of ADHD and/or anxiety disorders, as well as some "control" children from nearby schools without any identified psychiatric disorder (total of 141 kids).

They had mothers fill out questionnaires about their kids to get an idea of the kids' ADHD symptoms, anxiety symptoms, and SCT symptoms. They also gave the kids a variety of neuropsychological tests at their clinic to examine intelligence, attention, executive functions, and processing speed.

They were very strict about classifying kids as ADHD-PI to try to avoid including "subthreshold ADHD-C" kids (those kids who fit the "combined type" pattern but just miss the symptom cut-off).

What they found:
Kids with both ADHD + anxiety were more likely to have SCT symptoms than kids with only ADHD or only anxiety.

Kids with both ADHD-C and ADHD-PI were about equally likely to have SCT symptoms.

Kids with SCT didn't seem to have slower reaction times than other kids, but they had more variable spatial memory.


Study #2:
Barkley RA. Distinguishing sluggish cognitive tempo from attention deficit/hyperactivity disorder in adults. Journal of Abnormal Psychology(advance online publication). May 2011.

What he did:
Russell Barkley hired a firm to recruit a "nationally-representative" sample of adults, about half male and half female, ages 18+ from across the U.S.

The adults completed questionnaires to assess ADHD symptoms, SCT symptoms, executive function, functional impairment, and demographics and social variables.

He based his classification of "SCT" on a score in the 95th percentile or higher (meaning these adults were in the top 5% for SCT symptoms) based on questionnaire responses. ADHD was also classified based on a similar cut-off using his questionnaire.

What he found:
Of these adults, 33 had SCT but not ADHD, 46 had ADHD but not SCT, and 39 had both SCT + ADHD.

Of the adults with ADHD, they were evenly split by subtype: ~1/3 ADHD-PI, ~1/3 ADHD-HI, and ~1/3 ADHD-C (different from most studies of adults, which find very few ADHD-HI cases).

Adults with ADHD + SCT were about equally likely to have ADHD-PI or ADHD-C (but not many had ADHD-HI) -- and about 2/3 of both the ADHD-PI and ADHD-C people had SCT.

Adults with SCT alone seemed to have more difficulty with organization and problem-solving than adults with ADHD alone, but adults with ADHD + SCT had worse problems with these things.

Similarly, in terms of some life outcomes (occupational status, etc.), ADHD + SCT produced an extra whammy.

Take-home messages:
Maybe about 1/2 to 2/3 of people with ADHD who have a lot of impairing inattentive symptoms -- that includes both people with "Combined Type" and those with "Predominantly Inattentive Type" -- have high levels of SCT symptoms.

People can also have high levels of SCT symptoms without having high levels of classic ADHD symptoms.

The combination of ADHD + SCT seems to be associated with increased levels of anxiety, more difficulties in certain types of executive functions (which are not always affected by ADHD alone), and poorer functional outcomes in some areas.

We still have a lot to learn!

...But it's a start, and one that opens up the possibility of looking at SCT in a new way -- it's not the "opposite" of hyperactivity-impulsivity, but may in fact coexist with it.

Check this space for updates...and feel free to add questions, comments, or new information you come across!


Just a few of many caveats:
Keep in mind this is preliminary information about SCT. There is no scientific consensus yet on what it is, and what it's relationship is to ADHD.

Like a lot of cutting-edge info, it is likely to be refined and modified as more in-depth studies happen and scientists and clinicians get a better idea of what this thing (SCT) really is. Also, though these two papers were peer-reviewed and published in scientific journals, the researchers do have particular points of view that shaped the way they asked their questions.

Both studies also had limitations (which I won't discuss in detail because my head is tired) -- decisions the authors made when they conducted the studies, and the populations they studied, that make it more difficult to understand how their results might reflect the broader picture of messy real-world cases. This is almost always true of studies like this, not a flaw specific to this research. But as these were fairly small studies of a condition that no one is quite sure how to define, it's likely 10 years from now, we'll look back on these papers and get a better sense of just how far we've come in understanding this thing.

[Marzipan]

Yay, I wasn't talking out of my bum. Whole lot of good it'll do me. =(

I still haven't checked my thyroid levels and my iron count's a little low, so I guess there's still a little hope, but somehow I doubt that's where the issue's going to be.

[namazu]

Originally Posted by Marzipan

Yay, I wasn't talking out of my bum. Whole lot of good it'll do me. =(

On the plus side, studies like this are sure to generate a lot of attention (and perhaps research funding), so we're likely to learn a lot more about SCT and its relationship to ADHD (including what treatments may be most effective) in the next 5-10 years.

Small comfort to those dealing with it now...but it gives some hope for the future.

Meanwhile, you can call yourself cutting edge...pushing the boundaries of science!

[Marzipan]

That's true I guess. Seeing as how ADHD is already one of the highest-diagnosed mental health disorders, there will certainly be no shortage of research subjects. The sad thing is, it seems like there's a WHOLE lot of people out there who have SCT and don't realize it. No doubt they probably just think they're dumb or something. I suppose this might be a small comfort to many, even though it's not really treatable yet.

[namazu]

I wanted to add this for those new to this whole sluggish cognitive tempo / SCT business...

What does "SCT" look like?

Researchers have described SCT symptoms in various ways...

"sluggish/slow to respond”,
“seems to be in a fog”,
“drowsy or sleepy”,
“easily confused”, and
“daydreams/stares into space”

(from Skirbekk paper mentioned above, attributed to a 2004 paper by Hartmann and colleagues)

and/or

"Prone to daydreaming when I should be concentrating";
“have trouble staying alert or awake in boring situations”;
“easily confused”;
“easily bored”;
“spacey or in a fog”;
“lethargic, more tired than others”;
“underactive or have less energy than others”;
“slow moving”;
“I don’t seem to process information as quickly or as accurately as others.”

(from the Barkley paper mentioned above -- and I will note that this study was funded by the press who published his new ADHD rating scale, so file that in your "things to think about" bank)

and/or various other things that researchers thought/think/will eventually decide are related. The description will likely evolve, just as the defining symptoms of ADHD have changed over time.


Also, an editorial comment:

Is it just me, or is "sluggish cognitive tempo" about the most stigmatizing name anyone could possibly come up with? Who wants to be called "sluggish"? It's a fancy way of saying "slow"...

(And based on some of the papers I've seen, it looks like response time or other specific aspects of processing speed may not even be impaired in SCT...so it may not even be accurate.)

I hope that if/when this entity is formalized, The Powers That Be will think up an accurate-but-less-awful-sounding name!

[Marzipan]

Originally Posted by namazu

Is it just me, or is "sluggish cognitive tempo" about the most stigmatizing name anyone could possibly come up with? Who wants to be called "sluggish"? It's a fancy way of saying "slow"...

(And based on some of the papers I've seen, it looks like response time or other specific aspects of processing speed may not even be impaired in SCT...so it may not even be accurate.)

I hope that if/when this entity is formalized, The Powers That Be will think up an accurate-but-less-awful-sounding name!

Agreed, Sluggish Cognitive Tempo is a horrid name. It almost needs to come with an asterisk reminding people that it can occur in someone of any IQ.

As for the reaction issue, it depends what I'm reacting to. As someone with ADHD I have very quick reaction times to a lot of things. It's just detailed explanations, new or unfamiliar words, numbers, etc. that I have to pause and think about. Basically, abstract and foreign concepts, I guess. Once I've mastered them, though, I can respond as quick or quicker than anyone.

[danpan]

I'm diagnosed ADHD-PI, with all the symptoms of SCT, and I really don't mind the name.

I have a lot of trouble following a steam of information continuously, step by step, because my cognitive "tempo" doesn't beat in such short intervals. When people talk, that causes problems for me, just as it does when I'm reading, or trying to do anything else that requires me to manually process a constant stream of information.

I don't think of the term as derogatory, or implying that I'm slow in general, because it is specific and accurate in naming what is sluggish. Once I have internalized enough information, I skip from step 1 to step 5, to step 7, to step 12, so forth and so on, and then, when I reach a conclusion, I go back and fill in the blanks with a retroactive analysis.

In situations where information flow is at my discretion, and in a format suited to skipping around, I perform extremely quickly. Diagnosing problems with computers for example... often it only takes a few seconds to test a hypothesis, and from that, glean more information than a person could provide orally in 5 minutes of continuous chatter.

So my "tempo" is very slow, and the term is accurate, at least for me. It doesn't imply to me that I am a slow thinker. Just that my mind stops to consider new information in longer intervals than most, because it's always trying to skip ahead. It's often a curse, sometimes a boon.

(As a side-note, I think the reason I am so lethargic and tired all the time is because I can't "skip ahead" in thoughts related to day-to-day life, like driving, taking out the trash, doing dishes, etc. It's much easier to disengage completely and "turn off" the mind than face the anxiety and frustration that would result.)

[K-Funk]

OK, this is great to read b/c I totally have many combined/impulsive "traits" but also recognize a lot of myself when looking at definitions of SCT.

Great reasearch and info as always Namazy (which is my new nickname for you...so creative I know)

Originally Posted by namazu

Two recently-published studies suggest SCT is a separate disorder from ADHD, but co-occurs about 50% of the time -- and in both ADHD-PI and ADHD-C.

This could be filed under "scientific discussions", but I thought it would be of interest to a wider audience, so I put it here.

There's been a lot of talk recently about "sluggish cognitive tempo" or "SCT".

Unlike ADHD, SCT is not a formal diagnosis existing in the DSM-IV.

Rather, it's a collection of symptoms that have often been noticed by clinicians and researchers, often in people who are referred for ADHD evaluations or diagnosed with ADHD.

Symptoms of "SCT", as it is currently conceived, include things like "daydreamy", "processes information slowly", and "lethargic/hypoactive". There's not really a standard definition at the moment.

Some researchers (notably Russell Barkley) have argued that people diagnosed with the "Predominantly Inattentive" subtype of ADHD (ADHD-PI), who lack hyperactive-impulsive symptoms altogether, may really represent a separate group who would be better described by the SCT label than the ADHD label. Others have argued that ADHD really encompasses SCT.

In recent months, there have been a couple of eye-opening studies on SCT, and I wanted to summarize them for y'all.

Study #1:
Skirbekk B, Hansen BH, Oerbeck B, and Kristensen H. The relationship between sluggish cognitive tempo, subtypes of attention-deficit/hyperactivity disorder, and anxiety disorders. Journal of Abnormal Child Psychology 39(4):513-525. May 2011.

What they did:
The authors, working in Norway, identified kids ages 7-13 who were being seen in outpatient clinics for evaluation of ADHD and/or anxiety disorders, as well as some "control" children from nearby schools without any identified psychiatric disorder (total of 141 kids).

They had mothers fill out questionnaires about their kids to get an idea of the kids' ADHD symptoms, anxiety symptoms, and SCT symptoms. They also gave the kids a variety of neuropsychological tests at their clinic to examine intelligence, attention, executive functions, and processing speed.

They were very strict about classifying kids as ADHD-PI to try to avoid including "subthreshold ADHD-C" kids (those kids who fit the "combined type" pattern but just miss the symptom cut-off).

What they found:
Kids with both ADHD + anxiety were more likely to have SCT symptoms than kids with only ADHD or only anxiety.

Kids with both ADHD-C and ADHD-PI were about equally likely to have SCT symptoms.

Kids with SCT didn't seem to have slower reaction times than other kids, but they had more variable spatial memory.


Study #2:
Barkley RA. Distinguishing sluggish cognitive tempo from attention deficit/hyperactivity disorder in adults. Journal of Abnormal Psychology(advance online publication). May 2011.

What he did:
Russell Barkley hired a firm to recruit a "nationally-representative" sample of adults, about half male and half female, ages 18+ from across the U.S.

The adults completed questionnaires to assess ADHD symptoms, SCT symptoms, executive function, functional impairment, and demographics and social variables.

He based his classification of "SCT" on a score in the 95th percentile or higher (meaning these adults were in the top 5% for SCT symptoms) based on questionnaire responses. ADHD was also classified based on a similar cut-off using his questionnaire.

What he found:
Of these adults, 33 had SCT but not ADHD, 46 had ADHD but not SCT, and 39 had both SCT + ADHD.

Of the adults with ADHD, they were evenly split by subtype: ~1/3 ADHD-PI, ~1/3 ADHD-HI, and ~1/3 ADHD-C (different from most studies of adults, which find very few ADHD-HI cases).

Adults with ADHD + SCT were about equally likely to have ADHD-PI or ADHD-C (but not many had ADHD-HI) -- and about 2/3 of both the ADHD-PI and ADHD-C people had SCT.

Adults with SCT alone seemed to have more difficulty with organization and problem-solving than adults with ADHD alone, but adults with ADHD + SCT had worse problems with these things.

Similarly, in terms of some life outcomes (occupational status, etc.), ADHD + SCT produced an extra whammy.

Take-home messages:
Maybe about 1/2 to 2/3 of people with ADHD who have a lot of impairing inattentive symptoms -- that includes both people with "Combined Type" and those with "Predominantly Inattentive Type" -- have high levels of SCT symptoms.

People can also have high levels of SCT symptoms without having high levels of classic ADHD symptoms.

The combination of ADHD + SCT seems to be associated with increased levels of anxiety, more difficulties in certain types of executive functions (which are not always affected by ADHD alone), and poorer functional outcomes in some areas.

We still have a lot to learn!

...But it's a start, and one that opens up the possibility of looking at SCT in a new way -- it's not the "opposite" of hyperactivity-impulsivity, but may in fact coexist with it.

Check this space for updates...and feel free to add questions, comments, or new information you come across!


Just a few of many caveats:
Keep in mind this is preliminary information about SCT. There is no scientific consensus yet on what it is, and what it's relationship is to ADHD.

Like a lot of cutting-edge info, it is likely to be refined and modified as more in-depth studies happen and scientists and clinicians get a better idea of what this thing (SCT) really is. Also, though these two papers were peer-reviewed and published in scientific journals, the researchers do have particular points of view that shaped the way they asked their questions.

Both studies also had limitations (which I won't discuss in detail because my head is tired) -- decisions the authors made when they conducted the studies, and the populations they studied, that make it more difficult to understand how their results might reflect the broader picture of messy real-world cases. This is almost always true of studies like this, not a flaw specific to this research. But as these were fairly small studies of a condition that no one is quite sure how to define, it's likely 10 years from now, we'll look back on these papers and get a better sense of just how far we've come in understanding this thing.

[tired1823]

Whoever thought of the name is inconsiderate and I'm furious with that person right now.


I don't know.. I might have a touch of this. I did wellin school and teachers said I was smart. No one knows me as slow and I don't show that I get easily confused if I do. If I have this then saying I have something called sluggish cognitive tempo doesn't do me justice. They should really rename a lot of disorders.

[danpan]

Intermittent Attention Disorder? Heh

[tired1823]

Originally Posted by danpan

Intermittent Attention Disorder? Heh

that sounds better, way better

[ADHDTigger]

This makes sense to me. I am considered to be combined but ring the bell for every clarified symptom description in the DSM for inattention as well as hyperactivity and impulsivity. Using Barkley's list- which is, to me better defined...

Originally Posted by Barkley's definitions of SCT

"Prone to daydreaming when I should be concentrating";

Since I was a kid. I know that I need to concentrate but CAN'T. The harder I try, the worse it is. This was always a tick in the "inattentive" chart.

Originally Posted by Barkley's definitions of SCT

“have trouble staying alert or awake in boring situations”;

Ask me how often I have either fallen asleep outright in a meeting or am visibly snapping myself awake.

Originally Posted by Barkley's definitions of SCT

“easily confused”;

More often than I like to admit.

Originally Posted by Barkley's definitions of SCT

“easily bored”;

Yep. You need to catch my imagination quickly or I tune you out.

Originally Posted by Barkley's definitions of SCT

“spacey or in a fog”;

My brain could be San Francisco. Unless I am fully engaged. Then it is more like a laser that you don't want focused on you.

Originally Posted by Barkley's definitions of SCT

“lethargic, more tired than others”;

I've been blaming a lifetime of insomnia for this. I've had docs suggest that I have Chronic Fatigue Syndrome but I don't fit the criteria well enough.

Originally Posted by Barkley's definitions of SCT

“underactive or have less energy than others”;

All my life. I could live on the couch forever as long as my books/handwork/beadwork/etc is handy. I have little interest in going out to play.

Originally Posted by Barkley's definitions of SCT

“slow moving”;

Not the slowest, not the fastest. I tend to move slower now but there are other reasons.

Originally Posted by Barkley's definitions of SCT

“I don’t seem to process information as quickly or as accurately as others.”

New information takes me a few minutes to both comprehend and "fit". I ask questions using the "Tell me if I understand you" communication approach.

Interesting stuff. I just thought that it was the ADHD.

[AshT]

Originally Posted by namazu

I wanted to add this for those new to this whole sluggish cognitive tempo / SCT business...

What does "SCT" look like?

Researchers have described SCT symptoms in various ways...

"sluggish/slow to respond”,
“seems to be in a fog”,
“drowsy or sleepy”,
“easily confused”, and
“daydreams/stares into space”

(from Skirbekk paper mentioned above, attributed to a 2004 paper by Hartmann and colleagues)

and/or

"Prone to daydreaming when I should be concentrating";
“have trouble staying alert or awake in boring situations”;
“easily confused”;
“easily bored”;
“spacey or in a fog”;
“lethargic, more tired than others”;
“underactive or have less energy than others”;
“slow moving”;
“I don’t seem to process information as quickly or as accurately as others.”

(from the Barkley paper mentioned above -- and I will note that this study was funded by the press who published his new ADHD rating scale, so file that in your "things to think about" bank)

and/or various other things that researchers thought/think/will eventually decide are related. The description will likely evolve, just as the defining symptoms of ADHD have changed over time.


Also, an editorial comment:

Is it just me, or is "sluggish cognitive tempo" about the most stigmatizing name anyone could possibly come up with? Who wants to be called "sluggish"? It's a fancy way of saying "slow"...

(And based on some of the papers I've seen, it looks like response time or other specific aspects of processing speed may not even be impaired in SCT...so it may not even be accurate.)

I hope that if/when this entity is formalized, The Powers That Be will think up an accurate-but-less-awful-sounding name!

I really don't understand these symptoms...
I thought all people with ADHD were daydreamy? Except for those who were high on the Hyperactive side of things maybe.
And I thought basically all people with ADHD felt they walked around in a fog?

And I'm under-active but only mostly during the day time...I'm a night person through and through!

And I have slower processing skills than others because I have to go over my work a million times to make sure i've not made stupid mistakes! Not because i'm just 'slow'...

I really don't understand the differences!

[SirSleepsAlot]

I agree it should be separated and I do not mind being called "slow". To me it is not about the label it is about the awareness. I am nothing like the hyperactive or combined ADHD and the PI types are still much different which makes finding information is nearly impossible.

SCT is something I could tell someone who would have no idea what it is, which allows me to describe how it is not actually slow when they ask what it is.

[Jewelz81]

I've recently been diagnosed with ADHD-PI at 30, somthing I have suspected since high school... but only recently have I started researching SCT. I feel that this equally, if not better, describes me.

I've been researching some scholarly journal articles on SCT today, and I'll share, hoping it helps someone else as well. Forgive me if this info has already been posted somewhere.

Taken from: J Abnorm Child Psychol (2010) 38:1097–1107

Summary of this research article.........


"factor analytic techniques conducted during the field trials for the DSM-IV identified an additional cluster of symptoms termed SCT which was distinct from both the inattentive and hyperactive symptoms that were included in DSM-III (Lahey et al. 1994). The SCT factor comprised symptoms such as daydreaming, a tendency to become confused, a lack of alertness, and physical hypoactivity."

-- 3-Factor CFA Model of ADHD and SCT Symptoms:

SCT (range 0–2)

Confused or seems to be in a fog
Daydreams/gets lost in thoughts
Stares blankly
Apathetic/unmotivated (teacher only)

Inattention (range 0–3)

Fails to give close attention to details
Difficulty sustaining attention
Doesn’t listen
Doesn’t follow instructions
Difficulty organizing tasks/activities
Avoids/dislikes/reluctant to engage in work
Loses things necessary for tasks/activities
Is easily distracted
Is forgetful in daily activities

Hyperactivity/impulsivity (range 0–3)

Fidgets
Leaves seat
Seems restless
Difficulty engaging in activities quietly
“On the go”/“driven by a motor”
Talks excessively
Blurts out answers
Difficulty awaiting turn
Interrupts or intrudes on other



"Although these symptoms are related to ADHD symptoms of inattention, they may represent a separate dimension of ADHD or behavioral syndrome present across other clinical populations. Better understanding of the SCT phenotype would assist in determining whether these characteristics are unique to ADHD or if they represent an independent behavioral dimension contributing to overall impairment across a variety of psychopathological conditions."


"SCT symptoms were greatest in youth with ADHD Inattentive type, but were also found in non-ADHD clinical groups. SCT symptoms were related to inattention, internalizing, and social problems across both parent and teacher informants; for parent reports, SCT was also related to more externalizing problems. Findings support the statistical validity of the SCT construct, but its
clinical utility is still unclear."


Study design:

"The present study addresses gaps in existing research by examining the distinctiveness of SCT from ADHD and its relationship to adjustment problems in a clinical sampleTo address limitations in previous research, we utilize a sufficient number of SCT items and collect information from multiple informants (parents, teachers)."



Discussion:

"The present study provides empirical support for the validity of the SCT construct in a clinical sample of children and adolescents.

A confirmatory factor analysis confirmed that SCT symptoms form a distinct factor from symptoms of inattention and hyperactivity. Additionally, SCT symptoms were greater among males and individuals with a clinical diagnosis of ADHD-I.

However, relatively high levels of SCT symptoms were present among all diagnostic groups, including clinic-referred children who did not meet criteria for any clinical diagnosis. Finally, parent and teacher ratings of SCT were related to multiple aspects of adjustment, including internalizing problems, thought problems and social problems."


Limitations of study:

"One limitation of the current study was the use of only three or four items as a measure of SCT. In comparison, nine items were used to measure the inattentive and hyperactive/impulsive dimensions of ADHD.

Although the four SCT items used here may not be the best measure of the SCT construct, they have been widely used in existing research and until recently were the most feasibly-replicable measure of the SCT construct."



Conclusions:

"Since multiple studies point to attention problems as the primary area of
impairment for individuals with SCT, future studies should address whether the attention difficulties associated with SCT are different from attention difficulties seen in individuals with ADHD."






Reference:

Garner, A., Marceaux, J., Mrug, S., Patterson, C., & Hodgens, B. (2010). Dimensions and correlates of attention Deficit/Hyperactivity disorder and sluggish cognitive tempo. Journal of Abnormal Child Psychology, 38(8), 1097-107. doi:10.1007/s10802-010-9436-8


~ I will likely post some more on this, as I am curious to learn more, and perhaps others who suspect this subtype of themselves might learn from it also.