Dear reader of ADxS.org, please excuse the disruption.

ADxS.org needs around €58,500 in 2024. Unfortunately 99,8 % of our readers do not donate. If everyone reading this appeal made a small contribution, our fundraising campaign for 2024 would be over after a few days. This appeal is displayed 23,000 times a week, but only 75 people donate. If you find ADxS.org useful, please take a minute to support ADxS.org with your donation. Thank you very much!

Since 01.06.2021 ADxS.org is supported by the non-profit ADxS e.V. Donations to ADxS e.V. are tax-deductible in Germany (up to €300, the remittance slip is sufficient as a donation receipt).

If you would prefer to make an active contribution, you can find ideas for Participation or active support here.

$39778 of $63500 - as of 2024-09-30
62%
Header Image
15. Time and reaction time in ADHD

Sitemap

15. Time and reaction time in ADHD

Review: Dipl.-Psych. Waldemar Zdero

An altered perception of time is often reported in ADHD.
In addition, ADHD is characterized by an increased reaction time variance in reaction tests. The increased reaction time variance clearly distinguishes ADHD from other mental disorders such as anxiety, PTSD, ODD, CD and typical developmental disorders.
A slower reaction time and a larger standard deviation of the reaction time may be due to a lower decoding accuracy of the brain. Reaction time variance is particularly high in persons with ADHD who make many commission errors (confusion errors, false-positive errors). In addition, increased cortisol secretion correlates with an increased variance in response time.
ADHD shows a later and less pronounced slowing of reaction time after errors compared to non-affected individuals. Increased reaction time and reaction time variance also appear to correlate with a high availability of dopamine receptors, which is associated with reduced dopamine levels.

There is evidence of a shorter reaction time in ADHD, and even more so in SCT. In one study, reaction time to a stop signal, the percentage of failed response inhibitions, and the standard deviation of reaction time to the “go” trial (SDRT) successfully differentiated people with ADHD from those without. Ex-Gaussian decomposition of the reaction time distribution showed that both a larger tau and a larger sigma affected the results for the SDRT.1 Meanwhile, the traditional measures of inhibitory control were equally if not better predictors of ADHD status than the ex-Gaussian parameters.2

15.1. Reaction time variance increased in ADHD

ADHD is characterized by an increased variance in reaction time in reaction tests.345678 The increased reaction time variability is said to correlate in particular with problems of sustained attention, but this is controversial. Slower reaction time and greater standard deviation of reaction time also appears to be the Consequences of lower parieto-occipital multivariate decoding accuracy, which occurred approximately 240-340 ms after the onset of visual search.9101161213
Apparently, the response time variance is particularly high in the group of people with ADHD who make a particularly large number of commission errors (confusion errors, false-positive errors).14 Increased cortisol responses to a stressor correlated with an increased variance in response time.15 Elevated cortisol stress responses are very common in the ADHD-I subtype and atypical for the ADHD-HI subtype.
Furthermore, a later and reduced slowdown in reaction times after errors was reported than in those not affected.716
Increased individual response variance is a sign of increased neural noise. MPH improves this.17 Neural noise is represented by arrhythmic signals in the cortex, which can be measured as “1/f noise” in the EEG. Dopamine deficiency worsens the signal-to-noise ratio. ADHD is characterized by reduced dopamine levels in the PFC and striatum. Stimulants such as MPH increase the dopamine level there. An increase in dopamine levels to the optimal level improves the signal-to-noise ratio.
Increased reaction time and increased reaction time variability seem to correlate with a high availability of dopamine receptors (“empty receptors”), which is associated with reduced tonic dopamine levels.18

The symptom of increased reaction time variance also distinguishes ADHD significantly from other mental disorders such as

  • Fear
  • Distress disorders (physical stress disorders, PTSD)
  • Oppositional defiant behavior (ODD)
  • Disorder of social behavior (Conduct Disorder, CD)
  • Typical developmental disorders

We are currently testing a reaction test to explore whether reaction time variability can be used to diagnose ADHD. This is where the ADxS.org - ADHD reaction test starts.

15.2. Reduced reaction time in ADHD?

Several studies and reports indicate a shorter reaction time in ADHD.192021 117 According to Barkley, the reaction time is consistently reduced, especially with SCT (sluggish cognitive tempo)
According to another study, the reaction times of people with ADHD do not differ from those without ADHD, but the level of care does.
Contrary to all expectations, people with ADHD who carried the DRD4-7R gene polymorphism, which is one of the main candidates for increased sensitivity and ADHD, did not show poorer reaction times than non-affected people. However, carriers of other DRD4 polymorphisms did. Others reported deviating audiovisual multisensory processing.20
One study found a correlation of prolonged reaction times with ADHD-I.22

15.3. Rhythm problems

A study reports that people with ADHD have significantly more problems tapping out a given rhythm with their fingers.23 The test targets the function of the cerebellum, which is one of the brain regions involved in ADHD.
The difficulties correlated with the degree of hyperactivity/impulsivity. Higher impulsivity correlated with a faster tapping frequency,24

15.4. Changed perception of time

The perception of time is altered in ADHD.
This concerns the perception of different lengths of time, although perception for these different time windows is carried out by different regions of the brain.25

While time in the world around us has a uniform speed, the perception of this speed varies from person to person26
In ADHD, there are deficits in reproducing and estimating fixed durations. Children with ADHD tend to state the interval of a certain period of time longer than it was when estimating it, while they keep it too short when they are supposed to reproduce it.2728 People with ADHD therefore have a consistently deviating internal clock. The speed of cognitive functions based on temporal processing is increased. As a result, time passes subjectively faster for people with ADHD than for those not affected, so that real time is perceived as “sluggish”. According to the authors, this disorder in the subjective perception of time should explain the increased avoidance of delays, the stronger perception of boredom, the unpleasant perception of waiting times and the devaluation of distant rewards.
We consider this to be a misinterpretation. If time passes subjectively faster, a distant reward should become relatively more valuable compared to those who are not affected, as the reward subjectively occurs earlier. The correlation is nevertheless undisputed, we merely doubt the causality.

One hypothesis explains impulsivity symptoms of ADHD in particular with inter-individual differences in the perception of time of people with ADHD.2925 The time estimation of children with ADHD was even worse if they had particularly high impulsivity.30

One study found evidence that hyperactivity could be due less to reduced impulse inhibition than to an altered perception of time.31

A faster subjective time in ADHD was interpreted as an additional factor for a devaluation of distant rewards.25 However, this seems questionable to us, because if an objective period of time is subjectively perceived faster, this should be accompanied by a subjectively shorter perceived time, which should tend to counteract a devaluation of distant rewards.
However, there appears to be a more direct link between the devaluation of more distant rewards and impulsivity: subjective time perception can be experimentally assessed using hyperbolic delay discounting procedures to model the influence of time perception on decision making. Hyperbolic delay discounting describes the tendency (known from ADHD) to prefer smaller immediate rewards over larger but delayed rewards.25 This method thus assumes a direct link between the devaluation of more distant rewards and impulsivity.
Addiction research also reports a correlation between impulsivity and a devaluation of more distant rewards, which is attributed to an altered perception of time.32

In the hyperbolic discounting model, valuations fall relatively quickly at the beginning (e.g. for days 1 to 7), and more slowly for later periods (e.g. day 8 and later). IProbands considered it equivalent to receive USD 15 immediately, USD 30 after three months, USD 60 after one year or USD 100 after three years. Accordingly, the discount rates fell from 277% to 139% to 63% as the delay increased.33
This distinguishes the hyperbolic discounting model from a linear discounting model, in which the valuation decreases by the same amount for each unit of waiting time.

In a video game in which rewards were temporally decoupled from the action, people with ADHD performed as well as non-affected people in terms of executive function.34 One study reports that self-perception of attention difficulties in ADHD (and ASD) does not correlate with actual performance in attention tests.35

The perception of time is regulated in the brain by a complex network of timers, accumulators and comparison elements. The hippocampus and the entorhinal cortex are responsible for the longer measures of time and the cerebellum for the measures of time of fractions of a second, which are required in particular for brain-muscle coordination.36


  1. DeLuna-Castruita A, Lizarraga-Cortes V, Flores A, Manjarrez E (2023): ADHD Adults Show Lower Interindividual Similarity in Ex-Gaussian Reaction Time Vectors for Congruent Stimuli Compared to Control Peers. J Atten Disord. 2023 Dec 12:10870547231214966. doi: 10.1177/10870547231214966. PMID: 38084076.

  2. Galloway-Long, Huang-Pollock, Neely (2021): Ahead of the (ROC) Curve: A Statistical Approach to Utilizing Ex-Gaussian Parameters of Reaction Time in Diagnosing ADHD Across Three Developmental Periods. J Int Neuropsychol Soc. 2021 Sep 7:1-14. doi: 10.1017/S1355617721000990. PMID: 34488917. n = 550

  3. Salum, Sato, Manfro, Pan, Gadelha, do Rosário, Polanczyk, Castellanos, Sonuga-Barke, Rohde (2019): Reaction time variability and attention-deficit/hyperactivity disorder: is increased reaction time variability specific to attention-deficit/hyperactivity disorder? Testing predictions from the default-mode interference hypothesis. Atten Defic Hyperact Disord. 2019 Mar;11(1):47-58. doi: 10.1007/s12402-018-0257-x.

  4. Machida, Johnson (2019): Integration and segregation of the brain relate to stability of performance in children and adolescents with varied levels of inattention and impulsivity. Brain Connect. 2019 Aug 23. doi: 10.1089/brain.2019.0671.

  5. Gilbert, Huddleston, Wu, Pedapati, Horn, Hirabayashi, Crocetti, Wassermann, Mostofsky (2019): Motor cortex inhibition and modulation in children with ADHD. Neurology. 2019 Aug 6;93(6):e599-e610. doi: 10.1212/WNL.0000000000007899.

  6. Epstein, Erkanli, Conners, Klaric, Costello, Angold (2003): Relations between Continuous Performance Test performance measures and ADHD behaviors. J Abnorm Child Psychol. 2003 Oct;31(5):543-54.

  7. Liu, Hanna, Hanna, Rough, Arnold, Gehring (2020): Behavioral and Electrophysiological Correlates of Performance Monitoring and Development in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder. Brain Sci. 2020 Feb 2;10(2):E79. doi: 10.3390/brainsci10020079. PMID: 32024242.

  8. Ali S, Karr JE, MacDonald SWS, Macoun SJ (2024): Intraindividual Variability in Attention-Deficit/Hyperactivity Disorder: An Ex-Gaussian Approach. Child Psychiatry Hum Dev. 2024 Jun 17. doi: 10.1007/s10578-024-01722-1. PMID: 38886310.

  9. Paucke, Stibbe, Huang, Strauss(2019): Differentiation of ADHD and Depression Based on Cognitive Performance. J Atten Disord. 2019 Aug 13:1087054719865780. doi: 10.1177/1087054719865780.

  10. Saito, Kaga, Nakagawa, Okubo, Kohashi, Omori, Fukuda, Inagaki (2019): Association of inattention with slow-spindle density in sleep EEG of children with attention deficit-hyperactivity disorder. Brain Dev. 2019 Oct;41(9):751-759. doi: 10.1016/j.braindev.2019.05.004.

  11. Vortrag Barkley (2014) an der Lynn University, Minute 19:40

  12. Machida, Murias, Johnson (2019): Electrophysiological Correlates of Response Time Variability During a Sustained Attention Task. Front Hum Neurosci. 2019 Oct 15;13:363. doi: 10.3389/fnhum.2019.00363. eCollection 2019.

  13. Li D, Luo X, Guo J, Kong Y, Hu Y, Chen Y, Zhu Y, Wang Y, Sun L, Song Y (2022): Information-based multivariate decoding reveals imprecise neural encoding in children with attention deficit hyperactivity disorder during visual selective attention. Hum Brain Mapp. 2022 Oct 17. doi: 10.1002/hbm.26115. PMID: 36250701.

  14. Johnson, Kelly, Bellgrove, Barry, Cox, Gill, Robertson (2019): Response variability in attention deficit hyperactivity disorder: evidence for neuropsychological heterogeneity. Neuropsychologia. 2007 Mar 2;45(4):630-8.

  15. Lee, Shin, Stein (2010): Increased cortisol after stress is associated with variability in response time in ADHD children. Yonsei Med J 51:206–211

  16. Keute, Stenner, Mueller, Zaehle, Krauel (2019): Error-Related Dynamics of Reaction Time and Frontal Midline Theta Activity in Attention Deficit Hyperactivity Disorder (ADHD) During a Subliminal Motor Priming Task. Front Hum Neurosci. 2019 Oct 29;13:381. doi: 10.3389/fnhum.2019.00381. eCollection 2019.

  17. Pertermann, Bluschke, Roessner, Beste (2019): The Modulation of Neural Noise Underlies the Effectiveness of Methylphenidate Treatment in Attention-Deficit/Hyperactivity Disorder. Biol Psychiatry Cogn Neurosci Neuroimaging. 2019 Aug;4(8):743-750. doi: 10.1016/j.bpsc.2019.03.011.

  18. Lou, Rosa, Pryds, Karrebaek, Lunding, Cumming, Gjedde (2004): ADHD: increased dopamine receptor availability linked to attention deficit and low neonatal cerebral blood flow. Dev Med Child Neurol. 2004 Mar;46(3):179-83. doi: 10.1017/s0012162204000313. PMID: 14995087. n = 6

  19. Roshani, Piri, Malek, Michel, Vafaee (2019): Comparison of cognitive flexibility, appropriate risk-taking and reaction time in individuals with and without adult ADHD. Psychiatry Res. 2019 Jul 25:112494. doi: 10.1016/j.psychres.2019.112494.

  20. McCracken, Murphy, Burkitt, Glazebrook, Yielder (2020): Audiovisual Multisensory Processing in Young Adults With Attention-Deficit/Hyperactivity Disorder. Multisens Res. 2020 Jan 2:1-25. doi: 10.1163/22134808-20191472. n = 22

  21. Havenstein (2014): Arbeitsgedächtnisleistung und emotionale Interferenzkontrolle bei Erwachsenen mit Aufmerksamkeitsdefizit-/Hyperativitätsstörung (ADHS); Dissertation, Seite 43, n = 80

  22. 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

  23. Gustafsson P, Kjell K, Cundari M, Larsson M, Edbladh J, Madison G, Kazakova O, Rasmussen A (2023): The ability to maintain rhythm is predictive of ADHD diagnosis and profile. BMC Psychiatry. 2023 Dec 8;23(1):920. doi: 10.1186/s12888-023-05401-8. PMID: 38066477; PMCID: PMC10704849.

  24. Ben-Pazi H, Shalev RS, Gross-Tsur V, Bergman H (2006): Age and medication effects on rhythmic responses in ADHD: possible oscillatory mechanisms? Neuropsychologia. 2006;44(3):412-6. doi: 10.1016/j.neuropsychologia.2005.05.022. PMID: 16083921.

  25. White E, Dalley JW (2024): Brain mechanisms of temporal processing in impulsivity: Relevance to attention-deficit hyperactivity disorder. Brain Neurosci Adv. 2024 Aug 13;8:23982128241272234. doi: 10.1177/23982128241272234. PMID: 39148691; PMCID: PMC11325328. REVIEW

  26. Wittmann M (2009): The inner experience of time. Philos Trans R Soc Lond B Biol Sci. 2009 Jul 12;364(1525):1955-67. doi: 10.1098/rstb.2009.0003. PMID: 19487197; PMCID: PMC2685813. REVIEW

  27. Smith A, Taylor E, Rogers JW, Newman S, Rubia K (2002): Evidence for a pure time perception deficit in children with ADHD. J Child Psychol Psychiatry. 2002 May;43(4):529-42. doi: 10.1111/1469-7610.00043. PMID: 12030598.

  28. Toplak ME, Dockstader C, Tannock R (2006): Temporal information processing in ADHD: findings to date and new methods. J Neurosci Methods. 2006 Feb 15;151(1):15-29. doi: 10.1016/j.jneumeth.2005.09.018. PMID: 16378641. REVIEW

  29. Ptacek, Weissenberger, Braaten, Klicperova-Baker, Goetz, Raboch, Vnukova, Stefano (2019): Clinical Implications of the Perception of Time in Attention Deficit Hyperactivity Disorder (ADHD): A Review. Med Sci Monit. 2019 May 26;25:3918-3924. doi: 10.12659/MSM.914225. PMID: 31129679; PMCID: PMC6556068. REVIEW

  30. González-Garrido AA, Gómez-Velázquez FR, Zarabozo D, López-Elizalde R, Ontiveros A, Madera-Carrillo H, Vega OL, De Alba JL, Tuya JM (2008): Time reproduction disturbances in ADHD children: an ERP study. Int J Neurosci. 2008 Jan;118(1):119-35. doi: 10.1080/00207450601042177. PMID: 18041610.

  31. Sonuga-Barke EJ, Saxton T, Hall M (1998): The role of interval underestimation in hyperactive children’s failure to suppress responses over time. Behav Brain Res. 1998 Jul;94(1):45-50. doi: 10.1016/s0166-4328(97)00168-x. PMID: 9708838.

  32. Paasche C, Weibel S, Wittmann M, Lalanne L (2019): Time perception and impulsivity: A proposed relationship in addictive disorders. Neurosci Biobehav Rev. 2019 Nov;106:182-201. doi: 10.1016/j.neubiorev.2018.12.006. PMID: 30529361. REVIEW

  33. Thaler R (1981): Some empirical evidence on dynamic inconsistency, Economics Letters, Volume 8, Issue 3, 1981, Pages 201-207, ISSN 0165-1765, https://doi.org/10.1016/0165-1765(81)90067-7.

  34. Delisle J, Braun CM (2011): A context for normalizing impulsiveness at work for adults with attention deficit/hyperactivity disorder (combined type). Arch Clin Neuropsychol. 2011 Nov;26(7):602-13. doi: 10.1093/arclin/acr043. PMID: 21653627.

  35. Waldren LH, Leung FYN, Hargitai LD, Burgoyne AP, Liceralde VRT, Livingston LA, Shah P (2024): Unpacking the overlap between Autism and ADHD in adults: A multi-method approach. Cortex. 2024 Apr;173:120-137. doi: 10.1016/j.cortex.2023.12.016. PMID: 38387375.

  36. Grafik aus White E, Dalley JW (2024): Brain mechanisms of temporal processing in impulsivity: Relevance to attention-deficit hyperactivity disorder. Brain Neurosci Adv. 2024 Aug 13;8:23982128241272234. doi: 10.1177/23982128241272234. PMID: 39148691; PMCID: PMC11325328.