ADHD Comorbidities & Related Conditions

“Not Another Type of ADHD!”

Think you have ADHD, but the symptoms seem a little off? You could also be dealing with Concentration Deficit Disorder. Learn more about how it’s related to ADHD and why it requires an extra set of lifestyle changes.

Lethargic girl with concentration deficit disorder (CDD) and ADHD doing remote school
Lethargic girl with concentration deficit disorder (CDD) and ADHD doing remote school

As more parents and adults get educated about the symptoms of ADHD and its subtypes, discover treatments that work, and put a game plan together to help their child move forward in school and life, along comes a news flash from the research front that there may be another type of ADHD to contend with. It is called Concentration Deficit Disorder (CDD). You probably want to throw up your hands and shout, “Just what we need! Another type of ADHD to learn about and manage.”

What does Concentration Deficit Disorder look like in a child? He has persistent difficulty concentrating, and he stares or looks blank when he is asked a question. He is slow-moving, lethargic, drowsy, or sleepy during the day; uninterested in playing with friends; withdrawn.

A Scottish physician first described a pattern of behavior similar to CDD back in 1798. However, no one has been able to determine whether this pattern of behavior is a type of ADHD or a different disorder that often co-occurs with ADHD.

[Free Download: How to Focus (When Your Brain Says ‘No!’)?]

In the research literature, this cluster of symptoms is still called Sluggish Cognitive Tempo (SCT). However, for many people, the word “sluggish” is derogatory, because it suggests mental slowness, slow-wittedness, or outright laziness. Russell Barkley, Ph.D., recently made a plea to change the name to Concentration Deficit Disorder, which is less offensive and does not suggest that we understand the nature of the cognitive difficulties. The name change is a good suggestion. It focuses on the functional impairments of being drowsy, lacking energy, and being readily fatigued. Anyone who has had the flu knows that lack of energy and fatigue make it hard to concentrate on a task for more than a minute or so, or to engage in conversation or other social interaction.

Here is what the research community knows — and doesn’t know — about CDD. There are more questions than answers.

What Do We Know About CDD?

There is no agreement on the number or type of symptoms of CDD. Some research has been based on just two or three symptoms, while other studies have included as many as 14 symptoms. Some of the suggested symptoms of CDD are similar to symptoms of inattentive ADHD or a mood disorder. This makes it difficult to find out whether CDD differs from those conditions.

Is CDD a Form of Inattentive ADHD?

Some researchers found that a set of five symptoms was unique to CDD: “loses train of thought,” “easily confused,” “seems drowsy,” “is slow-thinking and slow-moving.” This set (or similar sets) of symptoms can be found in children, adolescents, and adults. Studies show that CDD symptoms are different from ADHD and mood disorders, although CDD often co-occurs with ADHD, particularly with the inattentive form. Parents, teachers, and clinicians shouldn’t assume that all problems with concentration or inattention mean that the individual has ADHD. However, a child or adult who has both CDD and ADHD is likely to be more severely impaired than those with either condition alone.

[Self-Test: Is It an Executive Function Deficit?]

Does CDD Occur With Disorders Other Than ADHD?

CDD often occurs with ADHD – up to 50 percent of children or adults with ADHD or CDD may have the other. However, even though children with ADHD often meet diagnostic criteria for Oppositional Defiant Disorder (ODD), children with CDD rarely have ODD or aggression. Moreover, many children, adolescents, and adults with CDD symptoms also have symptoms of mood disorders, but those with ADHD do not.

Since There Is No Known Way to Manage or Treat CDD, What Can I Do?

  • Make sure that the person with CDD symptoms gets enough sleep. Night-time sleep problems (difficulty falling asleep and staying asleep) are a major culprit in causing daytime sleepiness, lethargy, and difficulties in concentrating. Ask your doctor for advice about sleep hygiene.
  • Make sure that the person with CDD eats a nutritious breakfast. Skipping breakfast brings lower energy levels, tiredness, and a less positive mood. Eating a nutritious breakfast improves energy levels, mood, and cognitive function throughout the morning.
  • Take stock of how much exercise the person with CDD symptoms does daily. Regular exercise is beneficial for us all, but it may be particularly important for those with CDD.

How Does CDD Affect Friendships?

Individuals with CDD are more likely to be ignored by their peers. Those with ADHD, on the other hand, are often rejected by their peers because of their intrusiveness, bossiness, or excessive chatter. Peers might ignore those with CDD because they often have problems understanding subtle social cues – facial expressions or verbal intonation patterns – are slower to respond, or don’t respond, to conversation, and tend to withdraw from social interaction. So peers may think they are not fun to be with.

[The Attention Games: Catching Focus]

How Does CDD Affect A Child’s Performance In School?

Children and adolescents with CDD do not appear to have as many academic challenges as do youngsters with ADHD. Nor do they seem to have as much difficulty with executive functions compared to youngsters with attention deficit, no matter whether cognitive abilities are measured with tests or questionnaires.

What Can You Do About CDD?

Children suspected of having CDD are not clinically diagnosable at this point. This is because CDD symptoms are not currently recognized as either a distinct disorder or as a subtype of ADHD (or of another disorder) in the current version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V). This means that few clinicians, teachers, or other professionals know anything about CDD symptoms. There is no advocacy group for CDD to promote public awareness.

How Does CDD Affect Adults?

Studies of adults have shown that symptoms of CDD affect their physical abilities and their quality of life. Adults with CDD symptoms report that their symptoms interfere with their physical health — the ability to get around or to have enough energy for everyday life. By contrast, this does not occur in those with ADHD.

Both CDD and ADHD symptoms are related to poor psychological quality of life — affecting a person’s ability to concentrate and to perceive himself accurately. Thus, symptoms of CDD are not benign. They interfere with one’s quality of life, at least in adults.

What Do We Know and What Do We Not Know About CDD?

It is unclear whether CDD symptoms constitute a distinct disorder, a subtype of ADHD, or some other mental health disorder, in part because there have been so few studies done on it. Here is a rundown of what researchers know and don’t know:

  • We do know that CDD symptoms are found in children, adolescents, and adults, but researchers have not followed their subjects over months or years.
  • We don’t know whether CDD persists for several years or more.
  • We don’t know the natural course of the symptoms, if left untreated. We don’t know whether the symptoms disappear, remain constant, or increase, or whether they respond to ADHD medication.
  • We don’t know which aspects of cognitive function are impaired; in other words, we don’t know for sure that cognitive tempo is slow or sluggish.
  • We don’t know which treatments or management strategies are effective for CDD.
  • Virtually nothing is known about the causes of CDD. Preliminary evidence suggests that CDD symptoms might be heritable, but more research is needed to confirm this finding.

What Are The Takeaways About CDD?

There is growing support for the notion that CDD may be a clinical condition that is related to, but distinct from, ADHD, as well as from the symptom dimensions of ADHD (inattention, hyperactivity/impulsivity). Evidence to date indicates that symptoms of CDD can impair a person’s life, but more systematic research is needed to investigate CDD symptoms apart from ADHD.

8 Comments & Reviews

  1. Not that it has to be either or, CDD or sleep disorder – but in my family we have a genetic predisposition to both ADHD AND narcolepsy and/or hyper somnolence. Narcoleptic tendencies can be suspected via symptoms, a genetic test, a family member with a diagnosis and confirmed through a sleep test. I keep hoping that the relationship between these genetically passed neurotypical differences will be addressed by the ADHD community because I find that stimulants are certainly helpful both for focus and staying awake but they come at a cost that is hard to overcome. I can’t sleep at night which makes me foggy and strung out during the day. I guess I’m looking for a community who has figured out how to make it work.

  2. This notion between a family connection of narcolepsy and ADHD is so helpful. I would like to read more research and best practice articles. Our adult daughter has struggled with symptoms of both and because she did not come to us via birth we have limited health history or birth family support. We want to help her but she is difficult at best of times. Her personality changed as she entered mid teens. Didn’t know there was a genetic test for narcolepsy. Can someone expand. Thank you.

  3. I’m pretty sure I have this and have had it for 40 + years. Tired all the time..take a long time to do tasks especially written work and am easily distracted with little motivation. I wish they would make it an official diagnosis and work on treatments. Stimulants help but I have become tolerant to them after 4 years.

  4. Everyone, here is my concern. I could be way out in left field on this…however keep in mind it is only an opinion…and I’ve had plenty of wrong one’s in my life. Is anyone else concerned we are having too many ‘disorders’ identified? In the past X (meaning I don’t know exactly how many)…years it seems like anything that appears as a character flaw, or quirk, or personal idiosyncrasy gets it’s own ‘disorder’ or ‘syndrome’. My concern is it takes away from real disorders…and those that don’t have any (yeah right) use it to downplay the significance of legitimate one’s…e.g. – ADD, OCD, etc.

    Just a thought and a question. Thanks.

  5. Radaanak, I had a similar thought. That said, I feel like this article describes both my son and myself. I wasn’t diagnosed with ADHD until I was in my late 30s and had a child who was diagnosed with ADD. I still feel incredibly lethargic every single morning when I wake up and it takes several cups of coffee and at least an hour before I’m ready to face the day. Exercise and getting outside helps me the most. As a pediatric OT I have found that incorporating heavy work activities (for me – running, hiking and weight lifting) helps to increase arousal levels. So perhaps some of the symptoms that are being described are attributed to sensory processing.

  6. I have ADHD and had a sleep study 8 years ago showing mild sleep apnea (1 obstructive apneic event and the others were central), severely limited deep Non REM sleep, Periodic Limb Movement Disorder. I also have Restless Leg Syndrome which is better when my ferritin levels are normal. And I have always been tired and sluggish as long as I can remember. My new pulmonologist wonders if I have narcolepsy and so I am going to get a new sleep study. I have always wondered how many of us with the more sluggish type of adhd have underlying sleep disorders. My psych NP reminded me that the deep Non Rem sleep is what projects the brain from dementia and helps with memory. Awesome. I have absolutely no memory and it just gets worse as I age, esp my working memory.

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