Cognitive disengagement syndrome

Type of attention disorder

Cognitive disengagement syndrome (CDS) is an attention syndrome characterised by prominent dreaminess, mental fogginess, hypoactivity, sluggishness, slow reaction time, staring frequently, inconsistent alertness, and a slow working speed. To scientists in the field, it has reached the threshold of evidence and recognition as a distinct syndrome. Since 1798, the medical literature on disorders of attention has distinguished between at least two kinds, one a disorder of distractibility, lack of sustained attention, and poor inhibition (that is now known as ADHD) and the other a disorder of low power, arousal, or oriented/selective attention (now known as CDS). Although it implicates attention, CDS is distinct from ADHD. Unlike ADHD, which is the result of deficient executive functioning and self regulation, CDS presents with problems in arousal, maladaptive daydreaming, and oriented or selective attention (distinguishing what is important from unimportant in information that has to be processed rapidly), as opposed to poor persistence or sustained attention, inhibition and self regulation. In educational settings, CDS tends to result in decreased work accuracy, while ADHD impairs productivity. CDS can also occur as a comorbidity with ADHD in some people, leading to substantially higher impairment than when either condition occurs alone. In contemporary science today, it is clear that this set of symptoms is important because it is associated with unique impairments, above and beyond ADHD. CDS independently has a negative impact on functioning (such as a diminished quality of life, increased stress and suicidal behaviour, as well as lower educational attainment and socioeconomic status

Originally, CDS was thought to represent about one in three persons with the inattentive presentation of ADHD, and were more likely to be unmarried, out of work or on disability. CDS alone is also present in the population and can be quite impairing in educational and occupational settings, even if it is not as pervasively impairing as ADHD. The studies on medical treatments are limited, however, research suggests that atomoxetine may be used to treat CDS. The condition was previously called Sluggish Cognitive Tempo (SCT). The terms concentration deficit disorder (CDD) or cognitive disengagement syndrome (CDS) have recently been preferred to SCT because they better and more accurately explain the condition and thus eliminate confusion.

In many ways, those who have a CDS profile have some of the opposite symptoms of those with predominantly hyperactive impulsive or combined presentation of ADHD: instead of being hyperactive, extroverted, obtrusive, excessively energetic and risk takers, those with CDS are drifting, absent minded, listless, introspective and daydreamy. They feel like they are "in the fog" and seem "out of it". The comorbid psychiatric problems often associated with CDS are more often of the internalizing types, such as anxiety, unhappiness or depression. Most consistent across studies was a pattern of reticence and social withdrawal in interactions with peers. Their typically shy nature and slow response time has often been misinterpreted as aloofness or disinterest by others. In social group interactions, those with CDS may be ignored and neglected. People with classic ADHD are more likely to be rejected in these situations because of their social intrusiveness or aggressive behavior. Compared to children with CDS, they are also much more likely to show antisocial behaviours like substance abuse, oppositional defiant disorder or conduct disorder (frequent lying, stealing, fighting etc.). Accordingly, the ability to orient attention has been found to be abnormal in CDS. Both disorders interfere significantly with academic performance but may do so by different means. CDS may be more problematic with the accuracy of the work a child does in school and lead to making more errors. Conversely, ADHD may more adversely affect productivity which represents the amount of work done in a particular time interval. Children with CDS seem to have more difficulty with consistently remembering things that were previously learned and make more mistakes on memory retrieval tests than do children with ADHD. They have been found to perform much worse on psychological tests involving perceptual motor speed or hand eye coordination and speed. They also have a more disorganized thought process, a greater degree of sloppiness, and lose things more easily. The risk for additional learning disabilities seems equal in both ADHD and CDS (23–50%), but math disorders may be more frequent in the CDS group. They seem to lack energy to deal with mundane tasks and will consequently seek to concentrate on things that are mentally stimulating perhaps because of their underaroused state. Alternatively, CDS may involve a pathological form of excessive mind wandering. Such executive deficits pose serious problems for a person's ability to engage in self regulation over time to attain their goals and anticipate and prepare for the future. Adele Diamond postulated that the core cognitive deficit of those with ADHD I is working memory, or, as she coined in her recent paper on the subject, "childhood onset dysexecutive syndrome". That is to say that the majority of differences among individuals in these traits in the population may be due mostly to variation in their genes. The heritability of CDS symptoms in that study was only slightly lower than that for ADHD symptoms with a somewhat greater share of trait variation being due to unique environmental events. For instance, in ADHD, the genetic contribution to individual differences in ADHD traits typically averages between 75 and 80% and may even be as high as 90%+ in some studies. That for CDS maybe 50–60%. Little is known about the neurobiology of CDS. However, symptoms of CDS seem to indicate that the posterior attention networks may be more involved here than the prefrontal cortex region of the brain and difficulties with working memory so prominent in ADHD. This hypothesis gained greater support following a 2015 neuroimaging study comparing ADHD inattentive symptoms and CDS symptoms in adolescents: It found that CDS was associated with a decreased activity in the left superior parietal lobule (SPL), whereas inattentive symptoms were associated with other differences in activation. A 2018 study showed an association between CDS and specific parts of the frontal lobes, differing from classical ADHD neuroanatomy. A study showed a small link between thyroid functioning and CDS symptoms suggesting that thyroid dysfunction is not the cause of CDS. High rates of CDS were observed in children who had prenatal alcohol exposure and in survivors of acute lymphoblastic leukemia, where they were associated with cognitive late effects.

Cognitive disengagement syndrome is not included as a diagnosis in the current DSM (2013) and ICD (2022), either by its current name or as the outdated 'sluggish cognitive tempo', although it may be in subsequent versions; to scientists in the field, it has reached the threshold of evidence and recognition as a distinct syndrome Screening tools have been created to assess CDS symptoms. Although some symptoms of other conditions are partially shared with CDS, they are distinct conditions.

Treatment of CDS has not been well investigated. Initial drug studies were done only with the ADHD medication methylphenidate, and even then only with children who were diagnosed as ADD without hyperactivity (using DSM III criteria) and not specifically for CDS. The research seems to have found that most children with ADD (attention deficit disorder) with Hyperactivity (currently ADHD combined presentation) responded well at medium to high doses. However, a sizable percentage of children with ADD without hyperactivity (currently ADHD inattentive presentation, therefore the results may apply to CDS) did not gain much benefit from methylphenidate, and when they did benefit, it was at a much lower dose. However, one study and a retrospective analysis of medical histories found that the presence or absence of CDS symptoms made no difference in response to methylphenidate in children with ADHD I. as multiple randomised controlled clinical trials (RCTs) have found that it is an effective treatment. In contrast, multiple other RCTs have shown that it responds poorly to methylphenidate. Only one study has investigated the use of behavior modification methods at home and school for children with predominantly CDS symptoms and it found good success. In April 2014, The New York Times reported that sluggish cognitive tempo is the subject of pharmaceutical company clinical drug trials, including ones by Eli Lilly that proposed that one of its biggest selling drugs, Strattera, could be prescribed to treat proposed symptoms of sluggish cognitive tempo.

The prognosis of CDS is unknown. In contrast, much is known about the adolescent and adult outcomes of children having ADHD. Those with CDS symptoms typically show a later onset of their symptoms than do those with ADHD, perhaps by as much as a year or two later on average. Both groups had similar levels of learning problems and inattention, but CDS children had less externalizing symptoms and higher levels of unhappiness, anxiety/depression, withdrawn behavior, and social dysfunction. They do not have the same risks for oppositional defiant disorder, conduct disorder, or social aggression and thus may have different life course outcomes compared to children with ADHD HI and Combined subtypes who have far higher risks for these other "externalizing" disorders. This same pattern was recently found in the first study of adults with CDS by Barkley and also in more recent studies of college students. According to a Norwegian study, "[CDS] correlated significantly with inattentiveness, regardless of the subtype of ADHD."

There have been descriptions in literature for centuries of children who are very inattentive and prone to foggy thought. Symptoms similar to ADHD were first systematically described in 1775 by Melchior Adam Weikard and in 1798 by Alexander Crichton in their medical textbooks. Although Weikard mainly described a single disorder of attention resembling the combined presentation of ADHD, Crichton postulates an additional attention disorder, described as a "morbid diminution of its power or energy", and further explores possible "corporeal" and "mental" causes for the disorder (including "irregularities in diet, excessive evacuations, and the abuse of corporeal desires"). However, he does not further describe any symptoms of the disorder, making this an early but certainly non specific reference to an CDS like syndrome. The Canadian pediatrician Guy Falardeau, besides working with hyperactive children, also wrote about very dreamy, quiet and well behaved children that he encountered in his practice.

In more modern times, research surrounding attention disorders has traditionally focused on hyperactive symptoms, but began to newly address inattentive symptoms in the 1970s. Influenced by this research, the DSM III (1980) allowed for the first time a diagnosis of an ADD subtype that presented without hyperactivity. Researchers exploring this subtype created rating scales for children which included questions regarding symptoms such as short attention span, distractibility, drowsiness, and passivity. In the mid 1980s, it was proposed that as opposed to the then accepted dichotomy of ADD with or without hyperactivity (ADD/H, ADD/noH), instead a three factor model of ADD was more appropriate, consisting of hyperactivity impulsivity, inattention disorganization, and slow tempo subtypes. In the 1990s, Weinberg and Brumback proposed a new disorder: "primary disorder of vigilance" (PVD). Characteristic symptoms of it were difficulty sustaining alertness and arousal, daydreaming, difficulty focusing attention, losing one's place in activities and conversation, slow completion of tasks and a kind personality. The most detailed case report in their article looks like a prototypical representation of CDS. The authors acknowledged an overlap of PVD and ADHD but argued in favor of considering PVD to be distinct in its unique cognitive impairments. Problematic with the paper is that it dismissed ADHD as a nonexistent disorder (despite it having several thousand research studies by then) and preferred the term PVD for this CDS like symptom complex. A further difficulty with the PVD diagnosis is that not only is it based merely on 6 cases instead of the far larger samples of CDS children used in other studies but the very term implies that science has established the underlying cognitive deficits giving rise to CDS symptoms, and this is hardly the case. The research article and its accompanying commentary urging the undertaking of more research on CDS spurred the publication of over 30 scientific journal articles to date which specifically address symptoms of CDS. Allen Frances, emeritus professor of psychiatry at Duke University, argues: "We're seeing a fad in evolution: Just as ADHD has been the diagnosis du jour for 15 years or so, this is the beginning of another. This is a public health experiment on millions of kids I have no doubt there are kids who meet the criteria for this thing, but nothing is more irrelevant. The enthusiasts here are thinking of missed patients. What about the mislabeled kids who are called patients when there's nothing wrong with them? They are not considering what is happening in the real world."