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SCT - Sluggish Cognitive Tempo / Cognitive Disengagement Syndrome

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SCT - Sluggish Cognitive Tempo / Cognitive Disengagement Syndrome

SCT (Sluggish Cognitive Tempo) / CDS (Cognitive Disengagement Syndrome) used to be considered as a kind of sub-case or extreme case of ADHD-I. However, this view is outdated. SCT is a disorder in its own right and occurs in around 50% of those affected with and without comorbid ADHD.
In the presence of ADHD comorbidity, SCT appears to occur as frequently in ADHD-HI sufferers as in ADHD-I sufferers.

We consider the term “slowed thinking” to be inaccurate and inappropriate with regard to SCT. We rather perceive a slowed down decision making. The ability to think quickly is basically given; we suspect - as an unverified hypothesis - an overabundant blockade of the PFC by noradrenaline and possibly other neurotransmitters via the alpha-1-adrenoceptor.

1. Symptoms of SCT

In the following list of SCT symptoms, the numbers indicate how often the respective symptom occurs in SCT according to Becker et al.1. Lee et al.2 also name several of the symptoms as typical for SCT:

  • Quickly tired or exhausted 1.02
  • Low activity level, hypoactivity 0.97
  • Stares into space 0.96
  • Dozy, sleepy, yawning (during the day) 0.95
  • Forgets what he/she wanted to say 0.94
  • Inertia, slow movements 0.92
  • Quickly confused 0.91
  • Lost in the fog 0.89
  • Daydreams 0.88
  • Loses the train of thought 0.86
  • Slow thinking 0.82
  • Quickly gets confused 0.85
  • Lost in thought 0.81
  • Mental switch off 0.82
  • Difficulty expressing thoughts 0.78
  • Often considerable difficulty in making decisions (sluggish - in our experience)
  • Social seclusion3

A comprehensive review article found 13 distinct symptoms for SCT that are distinguishable from ADHD, but not distinct enough to be used diagnostically.4

One study found the Adult Concentration Inventory (ACI) to be appropriate for diagnosing SCT. 5 SCT was clearly associated with

  • Stronger internalizing symptoms
  • Time management and self-organization difficulties
  • Poorer sleep quality
  • Shorter sleep duration
  • Lower sleep efficiency
  • More daytime sleepiness.

SCT is not synonymous with reduced cognitive performance. There are highly gifted SCT sufferers. This is consistent with the finding that SCT does not correlate with slow processing speed.6

The slowed cognitive performance specific to the Sluggish/Underarousal subtype does not mean that intelligence would be reduced to the same degree. What is meant by this is that SCT is not the mere result of reduced intelligence. We know several individuals whom we perceive as SCT who have PhDs or are otherwise highly intelligent or even highly gifted. Rather, it appears that decision-making processes are slowed or impeded. Conversely, high IQ might mitigate SCT symptomatology.

The ADxS.org online SCT test (as of July 2020) showed a significant correlation of SCT symptoms with the reported highest IQ test score.

IQ subjects (n) SCT symptoms (out of 26)
140 and higher 38 12.9
130 - 139 83 13.8
120 - 129 51 14.6
110 - 119 25 15.0
100 - 109 15 17.5
90 - 99 7 17.5
80 - 89 5 14.8

30 Subjects with IQs of 130 and above scored very high on 20 or more SCT symptoms (out of a possible 26).

It can be assumed that subjects with lower IQ scores reported them less frequently. The values in the two IQ groups below 100 should be viewed with caution due to the low number of subjects.
Overall results are limited by the fact that subjects participated in the SCT online test linked to ADxS.org out of their own interest.
Data as of July 2020. (c) ADxS.org

Thus, the term sluggish cognitive tempo does not really seem appropriate. Barkley also disagrees with the SCT designation.7 In our opinion, Sluggish Decisioning Would be more appropriate. SCT sufferers, in our impression, fail particularly often as independents.

2. SCT (Sluggish Cognitive Tempo) as a disorder in its own right

SCT was previously described as a more extreme expression of ADHD-I subtype or ADHD-I-like type with slowed cognitive performance.8

A growing body of research, however, concludes that SCT is a distinct disorder that can be differentiated from ADHD.9101112131415161718 Strong distinctiveness from ADHD-I has been found for 13 of the 15 SCT symptoms.19

One study found evidence that SCT could be considered a group of symptoms that occurs in several mental disorders. When ADHD, depression, anxiety disorder, sleep disorders, and alcohol and cannabis abuse were taken out, less than 5% of subjects remained who had high SCT scores.20

A metastudy of 9 studies found acceptable to excellent reliability and high structural validity (high loading on an SCT factor and low loading on an ADHD-HI inattention factor) for the majority of SCT items.9

A large study of over 2,000 families found that among children, only 48% of those with SCT also had ADHD and only 35% of those with ADHD-HI also had SCT. Those with SCT without ADHD had higher levels of anxiety, depression, shyness, and sleep disturbances than those with ADHD without SCT. ADHD without SCT, on the other hand, had greater executive function deficits and more frequent ODD than those with SCT. SCT and ADHD did not differ in terms of friendships and social or academic impairments.21

However, SCT and ADHD appear to have significant comorbidity. One report suggests that 30% to 63% of ADHD-I sufferers also have significant SCT symptoms.2223

Barkley had already advocated in the early 2010s that SCT was a separate disorder, which has since been proven true. Meanwhile, in the early 2000s, he had similarly advocated that ADHD-I was a separate disorder from ADHD-HI, which has not proven to be true.

Results to date from the ADxS.org online questionnaire on SCT (as of July 2020) also indicate that SCT, while highly correlated with ADHD overall, is largely independent of ADHD-HI or ADHD-I subtypes. The mean scores of the n = 71 subjects with ADHD-HI and the n = 99 subjects with ADHD-I were nearly identical (ADHD-HI 15.7; ADHD-I 16.86 of 26 possible SCT symptoms when judged as they are when not taking ADHD medication). If ADHD sufferers assessed themselves as they are when taking ADHD medication, ADHD-HI sufferers had 13.21 symptoms (n = 16, minus 15.8%), whereas ADHD-I sufferers had 15.23 symptoms (n = 26, minus 9.7%). This suggests that ADHD medication may also have some positive impact on SCT symptoms.
In contrast, the n = 10 participants who stated that they certainly did not have ADHD and did not have SCT achieved an average SCT score of 8.4. To date, no participant stated that they certainly had SCT and did not have ADHD. This is not surprising due to the unfamiliarity of the disorder.

Men averaged 15.7 symptoms (n = 253), and women averaged 14.6 symptoms (n = 287) out of 26 possible symptoms.

Recent research indicates that SCT should differ from ADHD-I in the following ways:

  • SCT appears to correlate significantly more often than ADHD-I with
    • Later withdrawal from addictive substances13
    • Fear1213 21
      • In contrast, one study found no correlation between SCT and anxiety symptoms.18
    • Depression2412132118
    • Neuroticism25
    • Increased BIS25
    • Increased BAS fun-seeking25
  • SCT appears to be even more strongly associated with later internalizing behavior than ADHD-I.121319
  • SCT is reported to correlate (differently or more strongly than ADHD-I) with later shyness1321 or internalizing symptoms12 and lower extraversion25.
  • While externalizing symptoms were associated with hyperactivity/impulsivity symptoms of ADHD-HI in one study, internalizing symptoms were significantly correlated with SCT in ADHD-affected children and adolescents. Although social withdrawal was statistically significantly correlated with ADHD-I and inattention (compared with ADHD-HI), this relationship was mediated by SCT severity.26
  • SCT, like ADHD-I, is reported to correlate with later social difficulties,1213 but other studies do not confirm this.21
  • SCT shows even greater social withdrawal than ADHD, according to one study,2728 which another study only partially confirms.21
  • ADHD-I correlated with later poorer math performance and slower processing speed, whereas SCT more consistently predicted later poorer reading performance.13
  • SCT correlated (unlike other ADHD symptoms) with suicidal tendencies, which in turn correlated with depression.2919
  • SCT showed lower memory performance than ADHD-I and non-affected.30
  • Motor speed and reaction times
    • SCT showed not quite as reduced psychomotor speed and better neurocognitive index compared with ADHD-I.30
    • SCT showed faster reaction times than ADHD-I.30
    • Slower psychomotor speed and longer reaction times correlated with levels of inattention.30
    • In contrast to ADHD, SCT does not increase the variance of the reaction rate31
    • The unimpaired variance in reaction times at least tends to be consistent with a report that SCT had lower impairments in executive functions (mediated by working memory, like the variance in reaction times) than ADHD.21
  • SCT, unlike ADHD, is supposed to be
    • Occur equally often in men and women32
    • Occur just as frequently in adults as in children and adolescents, even if its onset is somewhat later than ADHD. Thus, there is no partial disappearance of symptoms in a subset of sufferers.32
    • In contrast, a 7-year longitudinal study of 639 twins found that SCT was usually short-lived (1 - 2 years) and had no lasting detrimental effect on academic achievement.12
  • SCT showed abnormalities in HRV compared with ADHD, which could indicate problems with arousal.33
  • SCT showed decreased conscientiousness.25
  • SCT sufferers who also have ADHD are said to be particularly frequent MPH nonresponders. In particular, elevated SCT Sluggish / Sleepy factor scores are said to indicate MPH nonresponding. In contrast, neither elevated SCT Daydreamy symptoms nor ADHD subtype (ADHD-HI or ADHD-I) differed in MPH responding rates (arguing against the present hypothesis of SCT as a subtype of ADHD-I).34
  • SCT, like ADHD, begins in early childhood, although in SCT symptoms increased moderately after age 5, whereas inattention remained more constant.35 SCT was subsequently distinguishable from ADHD, albeit highly correlative. Lower parental education correlated with higher SCT ratings by teachers. African Americans had higher inattention and lower teacher SCT ratings.
  • Unlike ADHD-I, SCT is not said to have features of emotional dysregulation.19
  • In a large study, SCT symptoms correlated with more frequent36
    • Mind wandering
    • Ponder
    • Daydreaming.
      The study further found the first empirical evidence of a unique and robust association between SCT symptoms and non-task-related thinking, while suggesting that the link between ADHD-HI and mind wandering may be less robust than previously thought.
  • SCT is reference to time representation, repetition of non-words, and remembering sentences’unremarkable. Instead, SCT seems to be more closely associated with features of a social (pragmatic) communication disorder.37

3. Neurophysiological characteristics of SCT

  • The specific SCT symptoms (sluggish, underarousal) could be caused by a noticeable deficit in the uptake of dopamine and norepinephrine.8
  • SCT is thought to correlate with inactivity in the superior parietal lobe (SPL).22
  • Sluggish Cognitive Tempo is said to correlate with attention problems, but not hyperactivity or aggression problems. Likewise, sleep problems are said to be less frequent.38
  • Sluggish cognitive tempo, unlike ADHD, is not conspicuous in the frontal and frontocentral theta-beta ratios of the EEG.39
  • SCT correlates with impaired information processing capacity and slowed (visual) information processing speed, according to one study.40
    Another study found no correlation of SCT with decreased information processing speed, but a correlation with decreased working memory speed as well as increased inhibition speed. Therefore, a combination of slowed working memory and accelerated inhibition was suspected.41
  • A high load on working memory significantly impairs information processing speed. Nevertheless, in ADHD, manipulations of working memory were not found to impair information processing speed, nor vice versa. This suggests that working memory impairments and Information Processing Speed impairments in ADHD are caused by different brain functional areas.42
  • One interesting report cites partial sleep of the brain as a possible cause of some SCT symptoms or mind wandering.43
  • Adolescents with SCT completed the Wechsler Symbol Search and Coding subtests and the Grooved Pegboard Test. Their parents reported no symptoms involving symbol search or coding scores about the affected individuals, whereas the affected individuals themselves reported significantly decreased coding scores. Parents and sufferers alike consistently reported symptoms that significantly correlated with slower Grooved Pegboard time. The hypothesis from this is that SCT correlates more clearly with performance on the processing speed task as motor demands increase.44
  • A study of children with ADHD aged 8 to 12 years measured SCT symptoms in relation to autonomic nervous system responses under social and cognitive stress. Respiratory sinus arrhythmia (RSA) and skin conductance level (SCL) reactivity were measured. SCT symptoms did not correlate with RSA reactivity in any stress variant. In social rejection stress, stronger SCT symptoms correlated with greater SCL reactivity. This pattern was independent of ADHD-HI symptoms, internalizing symptoms, medication status, or gender. The authors conclude that there is a link between SCT symptoms and sympathetic nervous system reactivityand greater BIS activation.45

4. Medication for SCT

  • In one study, atomoxetine significantly improved 7 of 9 Kiddie-Sluggish Cognitive Tempo Interview (K-SCT) symptoms in SCT. Symptom improvement in SCT was completely independent of ADHD symptoms.46 This also suggests that SCT is an independent disorder or has an independent disorder cause and can coexist with ADHD.
  • SCT sufferers are particularly likely to be MPH nonresponders, according to one study; in contrast, ADHD-HI and ADHD-I did not differ in MPH response rates in this study, which is controversial.34
  • One study found improvement in SCT symptoms with MPH only in relation to the school environment. Daydreaming and oppositional behavior correlated with lower MPH response in SCT.47
  • Results from the ADxS.org SCT online test suggest that ADHD medications may provide some improvement with respect to SCT symptoms (see above).

  1. Becker, Burns, Schmitt, Epstein, Tamm (2017): Toward Establishing a Standard Symptom Set for Assessing Sluggish Cognitive Tempo in Children: Evidence From Teacher Ratings in a Community Sample. Assessment. 2017 Jun 1:1073191117715732. doi: 10.1177/1073191117715732.

  2. Lee, Burns, Snell, McBurnett (2014): Validity of the sluggish cognitive tempo symptom dimension in children: sluggish cognitive tempo and ADHD-inattention as distinct symptom dimensions. J Abnorm Child Psychol. 2014 Jan;42(1):7-19. doi: 10.1007/s10802-013-9714-3.

  3. Fredrick, Becker (2022): Cognitive Disengagement Syndrome (Sluggish Cognitive Tempo) and Social Withdrawal: Advancing a Conceptual Model to Guide Future Research. J Atten Disord. 2022 Aug 4:10870547221114602. doi: 10.1177/10870547221114602. PMID: 35927980.

  4. Becker, Leopold, Burns, Jarrett, Langberg, Marshall, McBurnett, Waschbusch, Willcutt (2016): The Internal, External, and Diagnostic Validity of Sluggish Cognitive Tempo: A Meta-Analysis and Critical Review. J Am Acad Child Adolesc Psychiatry. 2016 Mar;55(3):163-78. doi: 10.1016/j.jaac.2015.12.006. n > 19000

  5. Fredrick, Burns, Langberg, Becker (2021): Examining the Structural and External Validity of the Adult Concentration Inventory for Assessing Sluggish Cognitive Tempo in Adults. Assessment. 2021 Jul 9:10731911211027224. doi: 10.1177/10731911211027224. PMID: 34243678. n = 286

  6. Cook, Braaten, Vuijk, Lee, Samkavitz, Doyle, Surman (2019): Slow Processing Speed and Sluggish Cognitive Tempo in Pediatric Attention-Deficit/Hyperactivity Disorder: Evidence for Differentiation of Functional Correlates. Child Psychiatry Hum Dev. 2019 Jun 21. doi: 10.1007/s10578-019-00904-6.

  7. Vortrag Barkley (2014) an der Lynn University, Minute 1:44

  8. Diamond: Attention-deficit disorder (attention-deficit/hyperactivity disorder without hyperactivity): A neurobiologically and behaviorally distinct disorder from attention-deficit (with hyperactivity), Development and Psychopathology 17 (2005), 807–825, Seite 810

  9. Becker (2020): Systematic Review: Assessment of Sluggish Cognitive Tempo Over the Past Decade. J Am Acad Child Adolesc Psychiatry. 2020 Oct 31:S0890-8567(20)32062-1. doi: 10.1016/j.jaac.2020.10.016. PMID: 33166623. REVIEW

  10. Burns, Becker (2019): Sluggish Cognitive Tempo and ADHD Symptoms in a Nationally Representative Sample of U.S. Children: Differentiation Using Categorical and Dimensional Approaches. J Clin Child Adolesc Psychol. 2019 Oct 31:1-14. doi: 10.1080/15374416.2019.1678165.

  11. Takeda, Burns, Jiang, Becker, McBurnett (2019): Psychometric properties of a sluggish cognitive tempo scale in Japanese adults with and without ADHD. Atten Defic Hyperact Disord. 2019 Mar 25. doi: 10.1007/s12402-019-00300-z.

  12. Vu, Thompson, Willcutt, Petrill (2019): Sluggish cognitive tempo: longitudinal stability and validity. Atten Defic Hyperact Disord. 2019 Feb 20. doi: 10.1007/s12402-019-00287-7.

  13. Becker, Burns, Leopold, Olson, Willcutt (2018): Differential impact of trait sluggish cognitive tempo and ADHD inattention in early childhood on adolescent functioning. J Child Psychol Psychiatry. 2018 Jun 29. doi: 10.1111/jcpp.12946.

  14. Garner, Peugh, Becker, Kingery, Tamm, Vaughn, Ciesielski, Simon, Loren, Epstein (2017): Does Sluggish Cognitive Tempo Fit Within a Bi-Factor Model of ADHD? J Atten Disord. 2017 Jun;21(8):642-654. doi: 10.1177/1087054714539995. n=168

  15. Barkley (2014): Sluggish cognitive tempo (concentration deficit disorder?): current status, future directions, and a plea to change the name; J Abnorm Child Psychol. 2014 Jan;42(1):117-25.

  16. Capdevila-Brophy, Artigas-Pallarés, Navarro-Pastor, García-Nonell, Rigau-Ratera, Obiols (2014): ADHD predominantly inattentive subtype with high sluggish cognitive tempo: a new clinical entity? J Atten Disord. 2014 Oct;18(7):607-16. doi: 10.1177/1087054712445483.

  17. McFayden, Jarrett, White, Scarpa, Dahiya, Ollendick (2020): Sluggish Cognitive Tempo in Autism Spectrum Disorder, ADHD, and Their Comorbidity: Implications for Impairment. J Clin Child Adolesc Psychol. 2020 Feb 6:1-8. doi: 10.1080/15374416.2020.1716365. PMID: 32027539.

  18. Brewe, Simmons, Capriola-Hall, White (2020): Sluggish cognitive tempo: An examination of clinical correlates for adults with autism. Autism. 2020 Feb 7:1362361319900422. doi: 10.1177/1362361319900422. PMID: 32028780. n = 57

  19. Becker, Burns, Smith, Langberg (2019): Sluggish Cognitive Tempo in Adolescents with and without ADHD: Differentiation from Adolescent-Reported ADHD Inattention and Unique Associations with Internalizing Domains. J Abnorm Child Psychol. 2019 Dec 9. doi: 10.1007/s10802-019-00603-9. n = 302

  20. Lovett, Wood, Lewandowski (2020): Differential Diagnosis of Sluggish Cognitive Tempo Symptoms in College Students. J Atten Disord. 2020 Jan 6:1087054719896856. doi: 10.1177/1087054719896856. n = 910

  21. Burns, Becker (2019): Sluggish Cognitive Tempo and ADHD Symptoms in a Nationally Representative Sample of U.S. Children: Differentiation Using Categorical and Dimensional Approaches. J Clin Child Adolesc Psychol. 2019 Oct 31:1-14. doi: 10.1080/15374416.2019.1678165. n = 2056 befragte Mütter

  22. Fassbender, Krafft, Schweitzer (2015): Differentiating SCT and inattentive symptoms in ADHD using fMRI measures of cognitive control; Neuroimage Clin. 2015; 8: 390–397; doi: 10.1016/j.nicl.2015.05.007; PMCID: PMC4474281

  23. Garner, Marceaux, Mrug, Patterson, Hodgens (2010): Dimensions and Correlates of Attention Deficit/Hyperactivity Disorder and Sluggish Cognitive Tempo; J Abnorm Child Psychol. 2010 Nov; 38(8): 1097–1107; doi: 10.1007/s10802-010-9436-8; PMCID: PMC3278310; NIHMSID: NIHMS353172

  24. Ward, Sibley, Musser, Campez, Bubnik-Harrison, Meinzer, Yeguez (2019): Relational impairments, sluggish cognitive tempo, and severe inattention are associated with elevated self-rated depressive symptoms in adolescents with ADHD. Atten Defic Hyperact Disord. 2019 Mar 9. doi: 10.1007/s12402-019-00293-9.

  25. Becker, Schmitt, Jarrett, Luebbe, Garner, Epstein, Burns (2018): Sluggish Cognitive Tempo and Personality: Links to BIS/BAS Sensitivity and the Five Factor Model. J Res Pers. 2018 Aug;75:103-112. doi: 10.1016/j.jrp.2018.06.001. n = 3172

  26. Sevincok, Ozbay, Ozbek, Tunagur, Aksu (2019): ADHD symptoms in relation to internalizing and externalizing symptoms in children: the mediating role of sluggish cognitive tempo. Nord J Psychiatry. 2019 Dec 6:1-8. doi: 10.1080/08039488.2019.1697746.

  27. Ferretti, King, Hilton, Rondon, Jarrett (2019): Social Functioning in Youth with Attention-Deficit/Hyperactivity Disorder and Sluggish Cognitive Tempo. Yale J Biol Med. 2019 Mar 25;92(1):29-35.

  28. Becker, Garner, Tamm, Antonini, Epstein (2017): Honing in on the Social Difficulties Associated With Sluggish Cognitive Tempo in Children: Withdrawal, Peer Ignoring, and Low Engagement. J Clin Child Adolesc Psychol. 2019 Mar-Apr;48(2):228-237. doi: 10.1080/15374416.2017.1286595.

  29. Becker, Holdaway, Luebbe (2018): Suicidal Behaviors in College Students: Frequency, Sex Differences, and Mental Health Correlates Including Sluggish Cognitive Tempo. J Adolesc Health. 2018 Aug;63(2):181-188. doi: 10.1016/j.jadohealth.2018.02.013. n = 1704

  30. Ünsel-Bolat, Ercan, Bolat, Süren, Bacanlı, Yazıcı, Rohde (2019): Comparisons between sluggish cognitive tempo and ADHD-restrictive inattentive presentation phenotypes in a clinical ADHD sample. Atten Defic Hyperact Disord. 2019 Mar 25. doi: 10.1007/s12402-019-00301-y. n = 155

  31. Barkley (2018): Vortrag an der Universität Göteborg, ca. Minute 41

  32. Barkley (2018): Vortrag an der Universität Göteborg, ca. Minute 35

  33. Yung, Lai, Chan, Ng, Chan (20129): Neuro-physiological correlates of sluggish cognitive tempo (SCT) symptoms in school-aged children. Eur Child Adolesc Psychiatry. 2019 May 27. doi: 10.1007/s00787-019-01353-1.

  34. Froehlich, Becker, Nick, Brinkman, Stein, Peugh, Epstein (2018): Sluggish Cognitive Tempo as a Possible Predictor of Methylphenidate Response in Children With ADHD: A Randomized Controlled Trial. J Clin Psychiatry. 2018 Feb 27;79(2). pii: 17m11553. doi: 10.4088/JCP.17m11553.

  35. Dvorsky, Becker, Tamm, Willoughby (2019): Testing the Longitudinal Structure and Change in Sluggish Cognitive Tempo and Inattentive Behaviors From Early Through Middle Childhood. Assessment. 2019 Nov 3:1073191119872247. doi: 10.1177/1073191119872247.

  36. Fredrick, Kofler, Jarrett, Burns, Luebbe, Garner, Harmon, Becker (2020): Sluggish cognitive tempo and ADHD symptoms in relation to task-unrelated thought: Examining unique links with mind-wandering and rumination. J Psychiatr Res. 2020 Apr;123:95-101. doi: 10.1016/j.jpsychires.2020.01.016. PMID: 32045730; PMCID: PMC7047632.

  37. Russell, Redmond, Ash (2022): Psycholinguistic profiling of children with sluggish cognitive tempo. Clin Linguist Phon. 2022 Jun 24:1-17. doi: 10.1080/02699206.2022.2092422. PMID: 35748339.

  38. Lee, Burns, Becker (2016): Can Sluggish Cognitive Tempo Be Distinguished From ADHD Inattention in Very Young Children? Evidence From a Sample of Korean Preschool Children; J Atten Disord. 2016 Nov 24. pii: 1087054716680077

  39. Jarrett, Gable, Rondon, Neal, Price, Hilton (2017): An EEG Study of Children With and Without ADHD Symptoms: Between-Group Differences and Associations With Sluggish Cognitive Tempo Symptoms. J Atten Disord. 2017 Aug 1:1087054717723986. doi: 10.1177/1087054717723986. n = 41

  40. Weiler, Bernstein, Bellinger, Waber (2002): Information processing deficits in children with attention-deficit/hyperactivity disorder, inattentive type, and children with reading disability. J Learn Disabil. 2002 Sep-Oct;35(5):448-61.

  41. Kofler, Irwin, Sarver, Fosco, Miller, Spiegel, Becker (2019): What cognitive processes are “sluggish” in sluggish cognitive tempo? J Consult Clin Psychol. 2019 Nov;87(11):1030-1042. doi: 10.1037/ccp0000446.

  42. Kofler, Soto, Fosco, Irwin, Wells, Sarver (2019): Working memory and information processing in ADHD: Evidence for directionality of effects. Neuropsychology. 2019 Oct 14. doi: 10.1037/neu0000598.

  43. Andrillon, Windt, Silk, Drummond, Bellgrove, Tsuchiya (2019): Does the Mind Wander When the Brain Takes a Break? Local Sleep in Wakefulness, Attentional Lapses and Mind-Wandering. Front Neurosci. 2019 Sep 13;13:949. doi: 10.3389/fnins.2019.00949. eCollection 2019.

  44. Becker, Marsh, Holdaway, Tamm (2019): Sluggish cognitive tempo and processing speed in adolescents with ADHD: do findings vary based on informant and task? Eur Child Adolesc Psychiatry. 2019 Nov 27. doi: 10.1007/s00787-019-01446-x. n = 80

  45. Becker, McQuade (2020): Physiological Correlates of Sluggish Cognitive Tempo in Children: Examining Autonomic Nervous System Reactivity during Social and Cognitive Stressor Tasks. J Abnorm Child Psychol. 2020 Jul;48(7):923-933. doi: 10.1007/s10802-020-00651-6. PMID: 32328864; PMCID: PMC7306431. n = 61

  46. McBurnett, Clemow, Williams, Villodas, Wietecha, Barkley (2017): Atomoxetine-Related Change in Sluggish Cognitive Tempo Is Partially Independent of Change in Attention-Deficit/Hyperactivity Disorder Inattentive Symptoms. J Child Adolesc Psychopharmacol. 2017 Feb;27(1):38-42. doi: 10.1089/cap.2016.0115. n = 124; this article is a response to the criticism of Yang, Li (2014): Could atomoxetine improve sluggish cognitive tempo symptoms? J Child Adolesc Psychopharmacol. 2014 Oct;24(8):462. doi: 10.1089/cap.2014.0052. PMID: 25285785, in which the original article Wietecha, Williams, Shaywitz, Shaywitz, Hooper, Wigal, Dunn, McBurnett (2013): Atomoxetine improved attention in children and adolescents with attention-deficit/hyperactivity disorder and dyslexia in a 16 week, acute, randomized, double-blind trial. J Child Adolesc Psychopharmacol. 2013 Nov;23(9):605-13. doi: 10.1089/cap.2013.0054. had been criticized for a failure to exclude ADHD symptoms from the evaluation of the effect of atomoxetine on SCT symptoms.

  47. Fırat, Gul, Aysev (2020): An Open-Label Trial of Methylphenidate Treating Sluggish Cognitive Tempo, Inattention, and Hyperactivity/Impulsivity Symptoms Among 6- to 12-Year-Old ADHD Children: What Are the Predictors of Treatment Response at Home and School? J Atten Disord. 2020 Feb 17:1087054720902846. doi: 10.1177/1087054720902846. PMID: 32064995. n = 185