Validation of the Mind Excessively Wandering Scale and the Relationship of Mind Wandering to Impairment in Adult ADHD

The Connection Between Mind Wandering, ADHD, and Level of Performance on an Attention Task

Background: ADHD is related to increased mind wandering (MW). However, it is not clear whether this is restricted by the methods used to measure MW in those studies. Moreover, it is not certain whether MW is an independent characteristic of people with ADHD or only due to their poor performance level in the primary task (the task from which attention wanders). Method: Participants with ADHD were compared to two control groups: high performers and low performers in the primary task who had a similar performance level to the ADHD group. Results: The ADHD group had greater MW than the two control groups, while no difference in MW was found between the two control groups. Conclusion: Increased MW is an independent characteristic of ADHD. This was further discussed within the context of different theories regarding ADHD and MW.

More than off-task: Increased freely-moving thought in ADHD

Off-task thought has been found to occur at high rates and is related to impairment in ADHD. However, off-task thought is heterogenous and it remains unclear which specific dimensions of off-task thought are more prevalent in this disorder. It is therefore important to dissociate different aspects of off-task thought in order to better understand the mechanisms underlying impairment. The current study focused on the dimension of constrained (focused) to freely moving off-task thought. Self-report and neurophysiological measures during a computerized attention tasks provided convergent evidence that individuals with ADHD not only have more off-task thought than those without, but also engaged in a greater proportion of freely moving off-task thought than non-ADHD controls. Overall, this work demonstrated differences in both the quantity and type of off-task thought in adults with ADHD. It provides novel insight into both the phenomenology of off-task thought, as well as potential mechanisms underlying impairment in ADHD.

Testing the construct validity of competing measurement approaches to probed mind-wandering reports

Psychology faces a measurement crisis, and mind-wandering research is not immune. The present study explored the construct validity of probed mind-wandering reports (i.e., reports of task-unrelated thought [TUT]) with a combined experimental and individual-differences approach. We examined laboratory data from over 1000 undergraduates at two U.S. institutions, who responded to one of four different thought-probe types across two cognitive tasks. We asked a fundamental measurement question: Do different probe types yield different results, either in terms of average reports (average TUT rates, TUT-report confidence ratings), or in terms of TUT-report associations, such as TUT rate or confidence stability across tasks, or between TUT reports and other consciousness-related constructs (retrospective mind-wandering ratings, executive-control performance, and broad questionnaire trait assessments of distractibility–restlessness and positive-constructive daydreaming)? Our primary analyses compared probes that asked subjects to report on different dimensions of experience: TUT-content probes asked about what they’d been mind-wandering about, TUT-intentionality probes asked about why they were mind-wandering, and TUT-depth probes asked about the extent (on a rating scale) of their mind-wandering. Our secondary analyses compared thought-content probes that did versus didn’t offer an option to report performance-evaluative thoughts. Our findings provide some “good news”—that some mind-wandering findings are robust across probing methods—and some “bad news”—that some findings are not robust across methods and that some commonly used probing methods may not tell us what we think they do. Our results lead us to provisionally recommend content-report probes rather than intentionality- or depth-report probes for most mind-wandering research.

Mind Wandering (Internal Distractibility) in ADHD: A Literature Review

Objective: Mind wandering, the unintended shifting of attention from a task, has been previously associated with symptoms of ADHD. To this end, we conducted a literature search to investigate the association between mind wandering and ADHD. Method: We conducted a systematic search of the literature of relevant articles assessing mind wandering and ADHD in PubMed, PsycINFO/OVID, and Medline. Included were original articles in English that had operationalized definitions of ADHD and mind wandering, adequate sample size, and reliance on statistical evaluation of findings. Excluded were reviews, opinions, and case reports. Results: Only nine studies met our a priori inclusion and exclusion criteria (N = 8 in adults; N = 1 in pediatrics). Findings suggest that ADHD is frequently associated with spontaneous mind wandering and when present heralds more functional impairments. Conclusion: The limited research on mind wandering in ADHD indicates that it is prevalent and morbid supporting further research on the subject.

Validation of the German Version of the Mind Excessively Wandering Scale (MEWS-G)

Increasing evidence shows that unintentional mind wandering is linked to Attention Deficit Hyperactivity Disorder (ADHD) and that its frequency contributes to symptom severity and functional impairment in ADHD. However, empirical data on mind wandering in adult ADHD are still scarce, and a validated scale to assess mind wandering in German adult ADHD patients is lacking. The primary aim of this study is to assess the psychometric properties of the German version of the recently published Mind Excessively Wandering Scale (MEWS-G) in terms of factorial structure and factor stability, internal consistency and construct validity. Analyses were performed in 128 adults with ADHD, clinical and healthy controls. As described for the original English 15-item version of the scale, we found lowest item-total-correlations for items 6, 10 and 14 with item-total correlation of all: 0.54/ADHD: 0.32 (item 6), all: 0.55/ADHD: 0.39 (item 10) and all: 0.11/ADHD: -0.04 (item 14). Item-total correlations for the remaining items were 0.65-0.86 and Cronbach Alpha was 0.96 indicating good internal consistency of the 12-item version of scale, on which we based all further analyses. Principal component analysis indicated a one- and two- factorial scale structure respectively explaining 71.7 % and 78.7 % of variance. Both factors showed good stability with lower stability of the factor-2 solution if sample size was reduced. The two-factorial solution also had many cross-loadings and a strong correlation of both factors in confirmatory factorial analysis (rf1f2 = 0.87). It probably describes related and interdependent, but not distinct facets of mind wandering, which strongly argues for the one factorial structure of the scale. Mean MEWS-G score in ADHD was 23.77 ± 7.85 compared to 7.64 ± 7.27 in controls (p < .0001). According to ROC, the optimal cut-off point to discriminate ADHD and controls is at MEWS-G score = 13. On the symptom level, MEWS-G score was correlated with ADHD, depressive and total psychiatric symptom scores, on the personality level with neuroticsm and negatively with conscientiousness and on the functional level with social interaction difficulties and impaired self-efficacy. In summary, our study shows that MEWS-G is a reliable, valid instrument to assess spontaneous mind wandering in adult ADHD and to discriminate between ADHD and controls.

Emotion recognition and mind wandering in adults with attention deficit hyperactivity disorder or autism spectrum disorder

Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) in adults are often undiagnosed and overlap in psychopathology. Here we investigated the transdiagnostic traits of emotion recognition and mind wandering in a sample of 103 adults (43 with ADHD and 14 with ASD). The ability to correctly identify a facial expression of anger, fear, disgust or surprise was no different between the adults with ADHD or ASD and neurotypical (NT) adults. However, adults with ADHD or ASD were on average almost 200 ms slower in making a correct decision, suggesting a larger speed-accuracy trade-off in facial emotion recognition compared to NT adults. General processing speed was associated with excessive mind wandering in adults with ADHD, but not with ASD. The deficits in emotional processing were independent from mind wandering in both adults with ADHD or ASD. Emotional dysregulation and functional impairment scales separated adults with ADHD and ASD from the NT adults, but not from each other. When controlling for self-reported ADHD and ASD symptom severity, mind wandering in ADHD was independent from both ADHD and ASD symptom severity. In ASD, mind wandering was related to ASD but not ADHD symptom severity. Our results suggest that ASD and ADHD share a slower ability to recognize emotions, which is exacerbated by excessive mind wandering in ADHD, and by decreased processing speed in ASD.

Electrophysiological modulation of sensory and attentional processes during mind wandering in attention-deficit/hyperactivity disorder

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Adults with ADHD relative to controls reported lower P1 during high demands on sustained attention.

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Adults with ADHD also showed lower P1 during task focus, but not during mind wandering than controls.

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Increased mind wandering frequency in ADHD might account for these between-group effects.

We recently reported increased mind wandering (MW) frequency in adults with attention-deficit/hyperactivity disorder (ADHD) relative to controls during high demands on sustained attention, reflecting deficient context regulation of MW. Studies on community samples previously linked context regulation of MW with attenuation in brain sensory processes, reflecting perceptual decoupling, and attentional processes during MW compared to task focus. However, the association between deficient context regulation of MW and these neural processes has not been studied in ADHD. We addressed this question by comparing adults with ADHD (N = 23) and controls (N = 25) on event-related potentials of early sensory processes (P1) and attention allocation (P3) during tasks manipulating cognitive demands (high vs low) on working memory and sustained attention, and during periods of MW and task focus measured through experience-sampling. Compared to controls, adults with ADHD showed reduced P1 during high sustained attention demands, as well as reduced P3 during high working memory demands. These group differences were no longer significant after adding MW frequency as a covariate. Across tasks, adults with ADHD showed no differences from controls on the P1 during MW episodes, but attenuated P1 during task focus. P3 was reduced in adults with ADHD compared to controls during MW, but not during task focus during the sustained attention task. These findings converge to indicate that impairments in early sensory processing in individuals with ADHD seem parallel to increased MW frequency and might reflect inefficient adjustments from periods of MW to task focus.

Electrophysiological correlates of spontaneous mind wandering in attention-deficit/hyperactivity disorder

We recently hypothesised that increased spontaneous mind wandering (MW-S) reflects a core process underlying attention-deficit/hyperactivity disorder (ADHD). Previous studies show that individuals with ADHD and neurotypical individuals with increased MW-S display similar cognitive-performance and electrophysiological (EEG) impairments in attentional processes. However, the cognitive-EEG markers associated with increased MW-S in ADHD remain poorly understood. We therefore investigated such markers in a sample of 69 sex- and age-matched adults with ADHD and 29 controls during the Sustained Attention to Response Task. We compared task performance and EEG measures (P3, time-frequency brain-oscillations) of attentional processes between groups, and examined their association with a validated self-report questionnaire of MW-S. Finally, we tested the hypothesis that MW-S and ADHD diagnosis relate to the same cognitive-EEG impairments using a hierarchical regression model. Compared to controls, adults with ADHD showed attenuations in P3, event-related alpha and beta suppression during response inhibition (No-Go trials), and theta power activations during response execution (Go trials), as well as increased reaction time variability and more commission/omission errors. MW-S was also continuously associated with most cognitive-EEG measures related to ADHD. The hierarchical regressions on measures associated with both ADHD diagnosis and MW-S showed that MW-S did not explain additional variance in the cognitive-EEG markers (except for beta suppression) beyond ADHD diagnosis, and vice versa. These findings are consistent with our hypothesis that ADHD diagnosis and MW-S share common neural deficits, and that MW-S may reflect a core symptom of the disorder.

Effects of L-theanine-caffeine combination on sustained attention and inhibitory control among children with ADHD: a proof-of-concept neuroimaging RCT

We examined the acute effects of L-theanine, caffeine and their combination on sustained attention, inhibitory control and overall cognition in boys with attention deficit hyperactivity disorder (ADHD). L-Theanine (2.5 mg/kg), caffeine (2.0 mg/kg), their combination and a placebo were administered in a randomized four-way repeated-measures crossover with washout, to five boys (8-15 years) with ADHD. Functional magnetic resonance imaging (fMRI) was performed during a Go/NoGo task and a Stop-signal task ~ 1 h post-dose. NIH Cognition Toolbox was administered ~ 2 h post-dose. Treatment vs. placebo effects were examined in multi-level mixed-effects models. L-Theanine improved total cognition composite in NIH Cognition Toolbox (p = 0.040) vs. placebo. Caffeine worsened and L-theanine had a trend of worsening inhibitory control (i.e. increased Stop-signal reaction time; p = 0.031 and p = 0.053 respectively). L-Theanine-caffeine combination improved total cognition composite (p = 0.041), d-prime in the Go/NoGo task (p = 0.033) and showed a trend of improvement of inhibitory control (p = 0.080). L-Theanine-caffeine combination was associated with decreased task-related reactivity of a brain network associated with mind wandering (i.e. default mode network). L-Theanine-caffeine combination may be a potential therapeutic option for ADHD-associated impairments in sustained attention, inhibitory control and overall cognitive performance.

Neurofunctional and behavioural measures associated with fMRI-neurofeedback learning in adolescents with Attention-Deficit/Hyperactivity Disorder

Functional Magnetic Resonance Imaging Neurofeedback (fMRI-NF) targeting brain areas/networks shown to be dysfunctional by previous fMRI research is a promising novel neurotherapy for ADHD. Our pioneering study in 31 adolescents with ADHD showed that fMRI-NF of the right inferior frontal cortex (rIFC) and of the left parahippocampal gyrus (lPHG) was associated with clinical improvements. Previous studies using electro-encephalography-NF have shown, however, that not all ADHD patients learn to self-regulate, and the predictors of fMRI-NF self-regulation learning are not presently known. The aim of the current study was therefore to elucidate the potential predictors of fMRI-NF learning by investigating the relationship between fMRI-NF learning and baseline inhibitory brain function during an fMRI stop task, along with clinical and cognitive measures. fMRI-NF learning capacity was calculated for each participant by correlating the number of completed fMRI-NF runs with brain activation in their respective target regions from each run (rIFC or lPHG); higher correlation values were taken as a marker of better (linear) fMRI-NF learning. Linear correlations were then conducted between baseline measures and the participants' capacity for fMRI-NF learning. Better fMRI-NF learning was related to increased activation in left inferior fronto-striatal regions during the fMRI stop task. Poorer self-regulation during fMRI-NF training was associated with enhanced activation in posterior temporo-occipital and cerebellar regions. Cognitive and clinical measures were not associated with general fMRI-NF learning across all participants. A categorical analysis showed that 48% of adolescents with ADHD successfully learned fMRI-NF and this was also not associated with any baseline clinical or cognitive measures except that faster processing speed during inhibition and attention tasks predicted learning. Taken together, the findings suggest that imaging data are more predictive of fMRI-NF self-regulation skills in ADHD than behavioural data. Stronger baseline activation in fronto-striatal cognitive control regions predicts better fMRI-NF learning in ADHD.

Sluggish cognitive tempo and ADHD symptoms in relation to task-unrelated thought: Examining unique links with mind-wandering and rumination

Recent theoretical and empirical evidence highlights associations between attention-deficit/hyperactivity disorder (ADHD) symptoms and task-unrelated thought, including mind-wandering and rumination. However, it has been hypothesized that sluggish cognitive tempo (SCT), characterized by daydreaming and staring behaviors, may uniquely relate to task-unrelated thought. The purpose of the present study was to test whether SCT symptoms are associated with greater mind-wandering and rumination, and whether this association remains when controlling for ADHD and internalizing symptoms. Participants (N = 4679; 18-29 years; 69% female; 80.9% White) enrolled in six universities in the United States completed measures of SCT, ADHD symptoms, internalizing symptoms, and rumination, as well as two scales used to assess mind-wandering. Although ADHD symptoms were correlated with greater self-reported mind-wandering and rumination, relations with mind-wandering on the daydreaming frequency scale, reflective rumination, and brooding rumination were attenuated when controlling for SCT and internalizing symptoms. Above and beyond other psychopathology dimensions, SCT symptoms were uniquely associated with greater self-reported mind-wandering and both reflective and brooding rumination. Additionally, SCT symptoms were more strongly associated than other psychopathology dimensions with the mind-wandering measure of daydreaming frequency. Results provide the first empirical support for unique and robust associations between SCT symptoms and task-unrelated thought, while suggesting that the link between ADHD and mind-wandering may be less robust than previously suggested.

Mind-wandering, depression, anxiety and ADHD: Disentangling the relationship

BACKGROUND

Mind Wandering (MW) has been associated with ADHD in a very small number of studies with adults and children. However, anxiety and depression have also been associated with MW and both are often comorbid with ADHD. The aim of this study was to investigate the role of anxiety and depression in MW in patients with ADHD.

METHODS

The Mind Excessively Wandering Scale (MEWS) compared the levels of MW controlling for the presence of anxiety and depression symptoms in 78 adolescents (53 males and 25 females) comprising ADHD, clinical controls and typically developing individuals. Correlational analysis between MEWS score, demographic variables, ADHD, anxiety and depressive symptoms was performed using simple and multiple linear regression analysis demonstrating that only anxiety predicted MW scores. On a second analysis, we compared Anxiety and Non-Anxiety as well as ADHD and non-ADHD groups.

RESULTS

Levels of MW were significantly correlated with anxiety symptoms, but not with depression. In addition, there were no differences in ADHD and non-ADHD groups regarding MW levels.

CONCLUSIONS

Our results suggest MW is associated with anxiety levels, independently of an ADHD diagnosis.

Randomised controlled trial of the short-term effects of OROS-methylphenidate on ADHD symptoms and behavioural outcomes in young male prisoners with attention-deficit/hyperactivity disorder (CIAO-II)

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent disorder, seen in 20-30% of young adult prisoners. Pharmacoepidemiological studies, a small randomised controlled trial and open trial data of methylphenidate suggest clinically significant reductions in ADHD symptoms, emotional dysregulation, disruptive behaviour and increased engagement with educational activities. Yet, routine treatment of ADHD in offenders is not yet established clinical practice. There is continued uncertainty about the clinical response to methylphenidate (MPH), a first-line treatment for ADHD, in offenders, who often present with an array of complex mental health problems that may be better explained by states of inattentive, overactive, restless and impulsive behaviours. To address this problem, we will conduct an efficacy trial to establish the short-term effects of osmotic-controlled release oral delivery system (OROS)-methylphenidate (Concerta XL), an extended release formulation of MPH, on ADHD symptoms, emotional dysregulation and behaviour.

METHODS

This study is a parallel-arm, randomised, placebo-controlled trial of OROS-MPH on ADHD symptoms, behaviour and functional outcomes in young male prisoners aged 16-25, meeting Diagnostic and Statistical Manual of Mental Disorders, fifth edition criteria for ADHD. Participants are randomised to 8 weeks of treatment with OROS-MPH or placebo, titrated over 5 weeks to balance ADHD symptom improvement against side effects. Two hundred participants will be recruited with a 1:1 ratio of drug to placebo. The primary outcome is change in level of ADHD symptoms after 8 weeks of trial medication.

DISCUSSION

Potential benefits include improvement in ADHD symptoms, emotional dysregulation, attitudes towards violence and critical incidents and increased engagement with educational and rehabilitation programmes. Demonstrating the efficacy and safety of MPH on ADHD symptoms and associated impairments may provide the data needed to develop effective healthcare pathways for a significant group of young offenders. Establishing efficacy of MPH in this population will provide the foundation needed to establish long-term effectiveness studies with the potential for demonstrating significant reductions in criminal behaviour and improved health-economic outcomes.

TRIAL REGISTRATION

ISRCTN registry, ISRCTN16827947, 31st May 2016; EudraCT number, 2015-004271-78, 31st May 2016. Last particpant last visit 6 June 2019. Data lock 27 August 2019.

Evaluating a scale of excessive mind wandering among males and females with and without attention-deficit/hyperactivity disorder from a population sample

Recent studies highlight the role of excessive mind wandering in attention-deficit/hyperactivity disorder (ADHD) and its association with impairment. We believe assessing mind wandering could be especially relevant to individuals, including many females, who present with less externalising manifestations of ADHD. Using a new measure based on ADHD patient reports, the Mind Excessively Wandering Scale (MEWS), we previously found adults with ADHD had elevated levels of mind wandering that contributed to impairment independently of core ADHD symptoms. Using data from an online general population survey, the current study assessed the factor-structure, reliability, validity and measurement invariance of the MEWS. We also investigated sex differences in mind wandering, as well as ADHD symptoms, impairment and wellbeing in those with and without ADHD. The MEWS had a unidimensional structure, was invariant across sex, age and ADHD status, and accounted for unique variance in impairment and wellbeing beyond core ADHD symptoms. Among those with ADHD, we found no evidence for sex differences in mind wandering and among those without ADHD males had higher scores. We also found similar levels of hyperactivity/impulsivity, emotional lability, and impairment in males and females with ADHD, but males reported greater inattention and lower wellbeing. Results suggest the MEWS is a reliable and valid instrument measuring the same construct across sex, age and ADHD status, which could aid diagnosis and monitoring of outcomes.

Genetic and environmental aetiologies of associations between dispositional mindfulness and ADHD traits: a population-based twin study

To get additional insight into the phenotype of attentional problems, we examined to what extent genetic and environmental factors explain covariation between lack of dispositional mindfulness and attention-deficit/hyperactivity disorder (ADHD) traits in youth, and explored the incremental validity of these constructs in predicting life satisfaction. We used data from a UK population-representative sample of adolescent twins (N = 1092 pairs) on lack of dispositional mindfulness [Mindful Attention Awareness Scale (MAAS)], ADHD traits [Conners' Parent Rating Scale-Revised (CPRS-R): inattentive (INATT) and hyperactivity/impulsivity (HYP/IMP) symptom dimensions] and life satisfaction (Students' Life Satisfaction Scale). Twin model fitting analyses were conducted. Phenotypic correlations (r_p) between MAAS and CPRS-R (INATT: r_p = 0.18, HYP/IMP: r_p = 0.13) were small, but significant and largely explained by shared genes for INATT (% r_p INATT-MAAS due to genes: 93%, genetic correlation r_A = 0.37) and HYP/IMP (% r_p HYP/IMP-MAAS due to genes: 81%; genetic correlation r_A = 0.21) with no significant contribution of environmental factors. MAAS, INATT and HYP/IMP significantly and independently predicted life satisfaction. Lack of dispositional mindfulness, assessed as self-reported perceived lapses of attention (MAAS), taps into an aspect of attentional functioning that is phenotypically and genetically distinct from parent-rated ADHD traits. The clinically relevant incremental validity of both scales implicates that MAAS could be used to explore the underlying mechanisms of an aspect of attentional functioning that uniquely affects life satisfaction and is not captured by DSM-based ADHD scales. Further future research could identify if lack of dispositional mindfulness and high ADHD traits can be targeted by different therapeutic approaches resulting in different effects on life satisfaction.

Mind wandering perspective on attention-deficit/hyperactivity disorder

Attention-Deficit/Hyperactivity Disorder (ADHD) is a common neurodevelopmental disorder associated with a range of mental health, neurocognitive and functional problems. Although the diagnosis is based on descriptions of behaviour, individuals with ADHD characteristically describe excessive spontaneous mind wandering (MW). MW in individuals with ADHD reflects constant mental activity which lacks topic stability and content consistency. Based on this review of the neural correlates of ADHD and MW, we outline a new perspective on ADHD: the MW hypothesis. We propose that altered deactivation of the default mode network, and dysfunctional interaction with the executive control network, leads to excessive and spontaneous MW, which underpins symptoms and impairments of ADHD. We highlight that processes linked to the normal neural regulation of MW (context regulation, sensory decoupling, salience thresholds) are deficient in ADHD. MW-related measures could serve as markers of the disease process, as MW can be experimentally manipulated, as well as measured using rating scales, and experience sampling during both cognitive tasks and daily life. MW may therefore be a potential endophenotype.

Mind wandering during attention performance: Effects of ADHD-inattention symptomatology, negative mood, ruminative response style and working memory capacity

OBJECTIVE

In adulthood, depressive mood is often comorbid with ADHD, but its role in ADHD-inattentiveness and especially relations with mind wandering remains to be elucidated. This study investigated the effects of laboratory-induced dysphoric mood on task-unrelated mind wandering and its consequences on cognitive task performance in college students with high (n = 46) or low (n = 44) ADHD-Inattention symptomatology and Hyperactivity/Impulsivity symptoms in the normal range.

METHODS

These non-clinical high/low ADHD-Inattention symptom groups underwent negative or positive mood induction after which mind wandering frequency was measured in a sustained attention (SART), and a reading task. Effects of ruminative response style and working memory capacity on mind wandering frequency were also investigated.

RESULTS

Significantly higher frequencies of self -reported mind wandering in daily life, in the SART and reading task were reported in the ADHD-Inattention symptom group, with detrimental effects on text comprehension in the reading task. Induced dysphoric mood did specifically enhance the frequency of mind wandering in the ADHD-Inattention symptom group only during the SART, and was related to their higher self-reported intrusive ruminative response styles. Working memory capacity did not differ between high/low attention groups and did not influence any of the reported effects.

CONCLUSIONS

These combined results suggest that in a non-clinical sample with high ADHD-inattention symptoms, dysphoric mood and a ruminative response style seem to be more important determinants of dysfunctional mind wandering than a failure in working memory capacity/executive control, and perhaps need other ways of remediation, like cognitive behavioral therapy or mindfulness training.

Shared and disorder-specific task-positive and default mode network dysfunctions during sustained attention in paediatric Attention-Deficit/Hyperactivity Disorder and obsessive/compulsive disorder

Patients with Attention-Deficit/Hyperactivity Disorder (ADHD) and obsessive/compulsive disorder (OCD) share problems with sustained attention, and are proposed to share deficits in switching between default mode and task positive networks. The aim of this study was to investigate shared and disorder-specific brain activation abnormalities during sustained attention in the two disorders. Twenty boys with ADHD, 20 boys with OCD and 20 age-matched healthy controls aged between 12 and 18 years completed a functional magnetic resonance imaging (fMRI) version of a parametrically modulated sustained attention task with a progressively increasing sustained attention load. Performance and brain activation were compared between groups. Only ADHD patients were impaired in performance. Group by sustained attention load interaction effects showed that OCD patients had disorder-specific middle anterior cingulate underactivation relative to controls and ADHD patients, while ADHD patients showed disorder-specific underactivation in left dorsolateral prefrontal cortex/dorsal inferior frontal gyrus (IFG). ADHD and OCD patients shared left insula/ventral IFG underactivation and increased activation in posterior default mode network relative to controls, but had disorder-specific overactivation in anterior default mode regions, in dorsal anterior cingulate for ADHD and in anterior ventromedial prefrontal cortex for OCD. In sum, ADHD and OCD patients showed mostly disorder-specific patterns of brain abnormalities in both task positive salience/ventral attention networks with lateral frontal deficits in ADHD and middle ACC deficits in OCD, as well as in their deactivation patterns in medial frontal DMN regions. The findings suggest that attention performance in the two disorders is underpinned by disorder-specific activation patterns.