Executive functioning and olfactory identification in young adults with attention deficit-hyperactivity disorder

Young adults with attention deficit-hyperactivity disorder (ADHD; N = 105) were compared with a control group (N = 64) on 14 measures of executive function and olfactory identification using a 2 (group) X 2 (sex) design. The ADHD group performed significantly worse on 11 measures. No Group X Sex interaction was found on any measures. No differences were found in the ADHD group as a function of ADHD subtype or comorbid oppositional defiant disorder. Comorbid depression influenced the results of only 1 test (Digit Symbol). After IQ was controlled for, some group differences in verbal working memory, attention, and odor identification were no longer significant, whereas those in inhibition, interference control, nonverbal working memory, and other facets of attention remained so. Executive function deficits found in childhood ADHD exist in young adults with ADHD and are largely not influenced by comorbidity but may be partly a function of low intelligence.     

Neuropsychological analyses of comorbidity between reading disability and attention deficit hyperactivity disorder: in search of the common deficit

Measures of component reading and language skills, executive functions, and processing speed were administered to groups of children with attention deficit hyperactivity disorder (ADHD; n = 113), reading disability (RD; n = 109), both RD and ADHD (n = 64), and neither RD nor ADHD (n = 151). Groups with RD exhibited pronounced deficits on all measures of component reading and language skills, as well as significant weaknesses on measures of verbal working memory, processing speed, and response inhibition. Groups with ADHD exhibited weaknesses on all response-inhibition and processing speed tasks and were impaired on some measures of component reading skills and verbal working memory. The group with comorbid RD and ADHD exhibited the combination of the deficits in the RD-only and ADHD-only groups, providing evidence against the phenocopy and cognitive subtype hypotheses as explanations for the co-occurrence of RD and ADHD. Slow and variable processing speed was characteristic of all 3 clinical groups, suggesting that measures of this domain may be useful for future studies that search for the common genes that increase susceptibility to RD and ADHD.     

Neuropsychological performance deficits in adults with attention deficit/hyperactivity disorder.

Neuropsychological deficits in children diagnosed with attention deficit/hyperactivity disorder (ADHD) have been well documented utilizing various neuropsychological tests. Only recently has research begun to examine if similar deficits are present in adults with ADHD. A neuropsychological testing battery was constructed that assessed verbal learning and memory, psychomotor speed, and sustained attention--all demonstrated to be deficient in individuals with ADHD. Fifty-six self-referred nonmedicated adults with a DSM-IV diagnosis of ADHD and 38 normal comparison adults participated. ADHD adults demonstrated verbal and nonverbal memory deficits and decreased psychomotor speed compared to normal controls. Differences between ADHD and normal adults were not documented on traditional measures of executive functioning. A pattern of results emerged whereby ADHD adults' performance, particularly with regard to psychomotor speed, became more impaired as task complexity increased. This study's results largely corroborate similar neuropsychological testing results in ADHD children and recent ADHD adult findings, and support a frontal lobe dysfunction hypothesis of ADHD.     

Characteristic neurocognitive profile associated with adult attention-deficit/hyperactivity disorder

BACKGROUND: It is now accepted that attention-deficit/hyperactivity disorder (ADHD) often persists into adulthood. However, relative to the considerable literature concerning the profile of neurocognitive deficits associated with this disorder in childhood, equivalent investigations in adult populations have been less common. The current study examined cognitive function in adults diagnosed with ADHD employing well-validated neuropsychological tasks. METHOD: Nineteen adult patients who satisfied DSM-IV criteria for ADHD and 19 matched (gender, age and verbal IQ), non-clinical control subjects were recruited. Patients were either unmedicated or had abstained from a psychostimulant medication regime for at least 24 h prior to neurocognitive assessment. A functionally wide-ranging test battery was administered. RESULTS: Relative to controls, ADHD adults performed significantly worse on spatial working memory, planning, and attentional-set shifting tests and were significantly slower to respond to target stimuli on the go/no-go task. In contrast, the two subject groups performed equivalently on decision-making and pattern/spatial recognition memory assessments. CONCLUSIONS: The demonstration of neuropsychological dysfunction in the adult ADHD cohort provides some support for the validity of this diagnosis in adulthood. In particular, there is broad consistency between the cognitive profile revealed in the current investigation and that previously demonstrated in a study of medication-na?ve ADHD children. There is evidence that frontostriatal function is especially disrupted.     

The relation between working memory components and ADHD symptoms from a developmental perspective

The objective was to examine the relations between attention deficit hyperactivity disorder (ADHD) symptoms and four working memory (WM) components (short-term memory and central executive in verbal and visuospatial domains) in 284 6-16-year-old children from the general population. The results showed that verbal and visuospatial short-term memory and verbal central executive uniquely contributed to inattention symptoms. Age interacted with verbal short-term memory in predicting inattention, with the relation being stronger in older children. These findings support the notion of ADHD as a developmental disorder, with changes in associated neuropsychological deficits across time. The results further indicate ADHD-related deficits in several specific WM components.     

Contribution of organizational strategy to verbal learning and memory in adults with attention-deficit/hyperactivity disorder

Statistical mediation modeling was used to test the hypothesis that poor use of a semantic organizational strategy contributes to verbal learning and memory deficits in adults with attention-deficit/hyperactivity disorder (ADHD). Comparison of 28 adults with ADHD and 34 healthy controls revealed lower performance by the ADHD group on tests of verbal learning and memory, sustained attention, and use of semantic organization during encoding. Mediation modeling indicated that state anxiety, but not semantic organization, significantly contributed to the prediction of both learning and delayed recall in the ADHD group. The pattern of findings suggests that decreased verbal learning and memory in adult ADHD is due in part to situational anxiety and not to poor use of organizational strategies during encoding.     

Rates and Patterns of Comorbidity Among First-Year College Students With ADHD

The purpose of this study was to examine rates and patterns of non–attention-deficit/hyperactivity disorder (non-ADHD) psychiatric diagnoses among a large group of 1st-year college students with and without ADHD. A total of 443 participants, including 214 men and 229 women ranging in age from 18 to 22 years of age (M = 18.2), were recruited from 9 colleges involved in a large-scale, multisite longitudinal investigation. Non-Hispanic Caucasian students represented 67.5% of the total sample. A comprehensive multimethod assessment approach was used in conjunction with expert panel review to determine both ADHD and comorbidity status. Significantly higher rates of overall comorbidity were found among college students with well-defined ADHD, with 55.0% exhibiting at least one comorbid diagnosis and 31.8% displaying two or more, relative to the corresponding rates of non-ADHD diagnoses among Comparison students, which were 11.2% and 4.0%, respectively. These differences in overall comorbidity rates were, in large part, attributable to the increased presence of depressive and anxiety disorders, especially major depressive disorder (active or in partial remission) and generalized anxiety disorder, among the students with ADHD. Within the ADHD group, differential comorbidity rates were observed as a function of ADHD presentation type and gender but not ethnic/racial diversity status. The current findings fill a gap in the literature and shed new light on the rates and patterns of comorbidity among emerging adults with ADHD in their 1st year of college. Implications for providing clinical and support services to college students with ADHD are discussed.     

Assessing symptoms of attention deficit hyperactivity disorder in children and adults: which is more valid?

The assessment of attention deficit hyperactivity disorder (ADHD) in adults has been a source of controversy. The authors tested competing ideas by evaluating familial transmission among adult and nonadult relatives of ADHD children. They analyzed ADHD symptom data collected by structured interviews from the members of 280 ADHD and 242 non-ADHD families. For both past and current symptoms, both the boys' and girls' families showed significantly more familial aggregation for adult relatives than for nonadult relatives. The results were similar for inattentive and hyperactive-impulsive symptoms and for relatives with and without psychiatric comorbidity. The results provide further evidence for the validity of adult ADHD and support the intriguing idea that, from a familial perspective, the assessment of ADHD may be more valid in adults than in children. They do not support the idea that parents of ADHD children are biased to report ADHD symptoms in themselves because of their exposure to an ADHD child.     

Cognitive functioning in a population-based sample of young adults with a history of non-psychotic unipolar depressive disorders without psychiatric comorbidity

BACKGROUND: There is evidence for cognitive dysfunction in unipolar depression among middle-aged and elderly patients, but cognitive functioning among depressed young adults has scarcely been systematically investigated. The aims of the present study were to examine cognitive functioning among depressed young adults identified from the general population and to determine whether cognitive deficits vary as a function of different disorder characteristics, such as severity and age at onset. METHODS: Performance in verbal and visual short-term memory, verbal long-term memory and learning, attention, processing speed, and executive functioning was compared between a population-based sample of 21-35-year-olds with a lifetime history of non-psychotic unipolar depressive disorders without psychiatric comorbidity (n=68) and healthy controls derived from the same population (n=70). RESULTS: Depressed young adults were not found to be impaired in any of the assessed cognitive functions, except for some suggestion of mildly compromised verbal learning. Nevertheless, younger age at depression onset was associated with more impaired executive functioning. LIMITATIONS: The results may slightly underestimate of the true association between depression and cognitive impairments in the young adult population due to possible dropout of participants. Additionally, the problem of multiple testing was not entirely corrected. CONCLUSION: The findings from this study indicate that a lifetime history of non-psychotic unipolar depressive disorders among young adults without psychiatric comorbidity may be associated only with minimal cognitive deficits, even when some residual depressive symptoms are prevalent. However, early-onset depression may represent a more severe form of the disorder, associated with more cognitive dysfunction.     

Neuropsychology of adults with attention-deficit/hyperactivity disorder: a meta-analytic review

A comprehensive, empirically based review of the published studies addressing neuropsychological performance in adults diagnosed with attention-deficit/hyperactivity disorder (ADHD) was conducted to identify patterns of performance deficits. Findings from 33 published studies were submitted to a meta-analytic procedure producing sample-size-weighted mean effect sizes across test measures. Results suggest that neuropsychological deficits are expressed in adults with ADHD across multiple domains of functioning, with notable impairments in attention, behavioral inhibition, and memory, whereas normal performance is noted in simple reaction time. Theoretical and developmental considerations are discussed, including the role of behavioral inhibition and working memory impairment. Future directions for research based on these findings are highlighted, including further exploration of specific impairments and an emphasis on particular tests and testing conditions.     

Neuropsychological performance in adult attention-deficit hyperactivity disorder: meta-analysis of empirical data.

Attention-deficit hyperactivity disorder (ADHD) is increasingly recognized not only in children but also in adults. Neuropsychological tests are important tools to quantify the attentional and/or cognitive deficits of patients compared to controls. The present meta-analysis integrates 24 empirical studies reporting results of at least one of 50 standard neuropsychological tests comparing adult ADHD patients with controls. The 50 tests were categorized into the following 10 functional domains: verbal ability, figural problem solving, abstract problem solving, executive function, fluency, simple attention, sustained attention, focused attention, verbal memory, figural memory. For each domain a pooled effect size d' was calculated. Complex attention variables and verbal memory discriminated best between ADHD patients and controls. Effect sizes for these domains were homogeneous and of moderate size (d' between 0.5 and 0.6). In contrast to results reported in children, executive functions were not generally reduced in adult ADHD patients.     

The impact of specific language impairment on working memory in children with ADHD combined subtype.

The objective of this study was to examine the impact of comorbid specific language impairment (SLI) on verbal and spatial working memory in children with DSM-IV combined subtype Attention Deficit Hyperactivity Disorder (ADHD-C). Participants were a clinical sample of 812- to 1212-year-old children diagnosed with ADHD-C. A group of ADHD-C with SLI was compared to a group of ADHD-C without SLI, and a group of normal children, matched on age and nonverbal intelligence. The results show that ADHD-C children with SLI scored significantly lower than those without SLI and normal children, on verbal working memory measures only. Both ADHD groups performed normally on spatial working memory measures. It is concluded that working memory deficits are not a specific characteristic of ADHD but are associated with language impairments. The importance of screening for language disorders in studies of neuropsychological functioning in children with ADHD is emphasized.     

成人ADHD患者静息脑电及其与生态执行功能的相关性

目的:探究成人注意缺陷多动障碍(ADHD)患者的脑电特征及其与生态执行功能的关系。方法:选取成人ADHD患者33例及正常对照30例,用执行功能行为评定量表成人版(BRIEF-A)评估生态执行功能,并记录静息态脑电,分析不同频段脑电的绝对功率,探讨其与执行功能缺陷的相关性。结果:与正常对照相比,ADHD患者BRIEF-A各因子得分及其全脑θ波及中央区β绝对功率均高于对照组(均P<0.01);ADHD患者的工作记忆评分与其双侧额叶θ波绝对功率呈正相关(r=0.43、0.49,均P<0.05),情感控制评分与双侧中央区β波绝对功率呈正相关(r=0.43、0.49,均P<0.05)。结论:成人ADHD患者生态执行功能存在缺陷,其额叶θ波及中央区-顶叶β波功率增高可能分别参与其工作记忆缺陷及情感控制不良的神经病理学机制。     

Neuropsychological and academic functioning in preschool boys with attention deficit hyperactivity disorder

We compared 34 preschool boys with attention deficit hyperactivity disorder (ADHD) to 30 community comparison boys without behavioral problems on a battery of neuropsychological and academic achievement tests along with behavioral observations. The battery of 25 measures was reduced to 4 dimensions through dimensional (factor) analysis. Comparison of the 2 groups revealed that boys with ADHD performed more poorly than comparison boys on 2 of the 4 dimensions, these being motor control and working memory‐persistence. No differences were found on the dimensions of verbal learning‐memory or picture identification‐factual knowledge. The results suggest that achievement problems are evident early in development in clinic‐referred children with ADHD and may be related to deficiencies in more fundamental neuropsychological functions. These early deficits in motor control and working memory seem to be an inherent part of ADHD, supporting both the neuromaturational nature of the disorder and current efforts to more broadly conceptualize it as involving deficits in executive functions beyond the core problems in behavioral inhibition and sustained attention.     

Are planning,working memory,and inhibition associated with individual differences in preschool ADHD symptoms?

The association between executive function (EF; planning, working memory, and inhibition) and individual differences in symptoms of attention deficit hyperactivity disorder (ADHD) was explored in a sample of preschool children. One hundred sixty children (between the ages of 3 years, 0 months and 5 years, 6 months), selected so as to oversample high ADHD scorers, performed 3 tasks previously shown to measure planning (Tower of London), working memory (Noisy Book) and inhibition ("Puppet Says..."). EF measures were reliable (kappa > .77) and were correlated with IQ (rs > .38) and age (rs > .59). Once IQ and age were controlled, planning and working memory (r = .41) were correlated. Planning and working memory were not correlated with inhibition (rs < .20). There was no association between ADHD and working memory or planning (rs < .12). There was a significant negative association between ADHD and conduct problems and inhibition (r = -.30 and r = -.25, respectively). Only the link with ADHD persisted after the effects of other factors were controlled for in a multiple regression. Specific deficits in inhibitory control rather than general EF deficits are associated with ADHD in the preschool period. This association is linear in nature, supporting the idea that ADHD is better seen as a continuum rather than a discrete category. This association provides evidence for Barkley's (1997) view that ADHD is underpinned by inhibitory deficits in the preschool period.     

Functional Impairments in Attention Deficit Hyperactivity Disorder: The Mediating Role of Neuropsychological Functioning

Attention deficit hyperactivity disorder (ADHD) is associated with multiple neuropsychological deficits and the present study aimed to investigate to what extent these deficits are related to the functional impairments associated with the disorder. The results showed that all executive functioning deficits and reaction time variability acted as mediators in the relation between ADHD and academic achievement. However, only the effect of working memory for language skills, and the effects of reaction time variability and working memory for mathematics, remained significant when studying independent effects. Regulation of anger was a significant mediator for peer problems. Gender or symptoms of oppositional defiant disorder (ODD) or conduct disorder (CD) did not moderate these findings.     

Time estimation and performance on reproduction tasks in subtypes of children with attention deficit hyperactivity disorder.

This study compared Hispanic children (ages 7 to 11) with combined type (CT, n=33) and inattentive type (IT, n=21) attention deficit hyperactivity disorder (ADHD) and a control group (n=25) on time-estimation and time-reproduction tasks. The ADHD groups showed larger errors in time reproduction but not in time estimation than the control group, and the groups did not differ from each other on their performance on this task. Individual differences could not be accounted for by oppositional-defiance ratings and low math or reading scores. Although various measures of executive functioning did not make significant unique contributions to time estimation performance, those of interference control and nonverbal working memory did so to the time-reproduction task. Findings suggest that ADHD is associated with a specific impairment in the capacity to reproduce rather than estimate time durations and that this may be related to the children's deficits in inhibition and working memory.     

Time Estimation and Performance on Reproduction Tasks in Subtypes of Children With Attention Deficit Hyperactivity Disorder

This study compared Hispanic children (ages 7 to 11) with combined type (CT, n = 33) and inattentive type (IT, n = 21) attention deficit hyperactivity disorder (ADHD) and a control group (n = 25) on time-estimation and time-reproduction tasks. The ADHD groups showed larger errors in time reproduction but not in time estimation than the control group, and the groups did not differ from each other on their performance on this task. Individual differences could not be accounted for by oppositional-defiance ratings and low math or reading scores. Although various measures of executive functioning did not make significant unique contributions to time estimation performance, those of interference control and nonverbal working memory did so to the time-reproduction task. Findings suggest that ADHD is associated with a specific impairment in the capacity to reproduce rather than estimate time durations and that this may be related to the children's deficits in inhibition and working memory.     

注意缺陷多动障碍儿童记忆和学习的研究

目的：探讨注意缺陷多动障碍DSM－Ⅳ亚型记忆学习功能及与持续性注意的关系。方法：对113名8－12岁注意缺陷我动障碍男童与83名正常儿童对照研究，并与持续性注意测验进行相关分析。结果：ADHD各亚型图案记忆成绩均较对照组差；混合型儿童的图片记忆，言语记忆和故事记忆成绩较对照组差。持续性注意测验的击中度，虚报数，d‘值与记忆和学习相关。结论：注意缺陷多动障碍儿童存在记忆与学习功能损害，与注意障碍明显相关。     

Psychiatric comorbidity in Korean children and adolescents with attention-deficit hyperactivity disorder: psychopathology according to subtype

It is well-known that more than 50% of attention-deficit hyperactivity disorder (ADHD) cases also have comorbid psychiatric disorders. We evaluated the comorbid psychopathology of Korean children and adolescents with ADHD using a standardized diagnostic instrument. The Korean Kiddie-Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL-K) was administered and completed in 105 patients who had been referred to the outpatient and inpatient clinics at the Samsung Medical Center from March 2004 to May 2005. All of the cases were diagnosed as ADHD according to DSM-IV criteria. We analyzed their clinical characteristics and psychiatric comorbidities, and assessed the correlation of any comorbidity with gender, age and ADHD subtype. Among our 105 participants, 70 (66.7%) subjects were diagnosed with combined-type ADHD, 22 (21.0%) were the predominantly inattentive type, only 1 (1.0%) was determined to have the predominantly hyperactive-impulsive type of ADHD, and 12 (11.4%) were classified as not otherwise specified (NOS) ADHD. Eighty (76.2%) subjects had at least one comorbid disorder such as oppositional defiant disorder (n = 53, 50.5%), anxiety disorders (n = 35, 33.3%) and affective disorders (n = 15, 14.3%). Our patients ranged in age from five to 16 years. Among the factors including gender, age, and ADHD subtype, ADHD subtype was the only one significant to comorbidity in our study. The results of this study suggest that psychiatric comorbidity in Korean children with ADHD is similar to the results of previous studies in western countries. Out of all the ADHD subtypes, the combined-type group had a significantly higher ratio of comorbid disorders and psychopathologies.