The diagnosis and neuropsychological assessment of adult attention deficit/hyperactivity disorder. Scientific study and practical guidelines

Questionnaire ratings of attention-deficit/hyperactivity disorder (ADHD) in adults are associated with spatial working memory

OBJECTIVE

Data related to brain function may have the potential to improve the reliability and validity of assessments for the aetiologically and clinically heterogeneous syndrome of attention-deficit/hyperactivity disorder (ADHD). This study investigated associations between questionnaire assessments of behavioural features of adults with ADHD and an aspect of neurocognitive performance which has been reported to be impaired in adults with ADHD.

METHODS

Fifty-nine adult patients with a DSM-IV diagnosis of ADHD, and their informants, completed questionnaires related to aspects of severity of ADHD. Associations were examined between questionnaire ratings and performance on a computer-administered task of spatial working memory (SWM).

RESULTS

Correlations between ratings of ADHD and SWM indicated moderate but significant correlations for patients' ratings, but not for informants' ratings. Also, patients who reported a past history of 'self-harm' (N=33) had a significantly worse mean performance on both measures of SWM (p=0.004, 0.003).

CONCLUSIONS

The results indicate that aspects of impulsivity, i.e. self-ratings of 'emotive' behaviour (involving rapid response to stimuli and marked reactivity of mood) and of past 'self-harm', show relatively strong associations with SWM performance in adults selected on the basis of an ADHD diagnosis. A profile of neurocognitive performances may have a role in the assessment of ADHD.

Specific pattern of attentional changes in impulsive individuals

INTRODUCTION

Although impulsivity is recognised as a major psychopathological feature, its cognitive correlates remain controversial. We evaluated readiness to act induced by a warning signal and attentional engagement in healthy impulsive participants.

METHODS

People with high impulsivity scores (HI) and low impulsivity (LI) scores on Barratt's Impulsivity Scale (BIS) were selected among 1250 students from top and bottom deciles. Subjects with personal or family of lifetime Axis I disorders were excluded. Motor preparation was evaluated by a Choice Reaction Time task (CRT) with a randomly presented warning signal with a delay before target of 500 ms or 2000 ms depending on the trial block. Attentional engagement and maintenance of fixation was evaluated by a Cued Target Detection task (CTD) comparing cued (valid, invalid, or double cue) and uncued trials and contrasting fixation offset (gap) or maintenance (overlap) conditions.

RESULTS

HI, but not LI participants had a shortened reaction time in the 2000 ms condition of CRT with warning signal, indicating a persistent readiness to act. In contrast to LI, HI showed a decreased reinforcement of attention in the overlap condition of CTD with a hyperreactivity to all types of visual stimuli.

CONCLUSIONS

Impulsivity per se appears to be associated with hyperreactivity to warning or cue signals and on inability to maintain attentional fixity.

Executive functions and ADHD in adults: evidence for selective effects on ADHD symptom domains

Dual-process models of attention-deficit/hyperactivity disorder (ADHD) suggest that both executive functioning and regulatory functions (e.g., processing speed) are involved and that executive function weaknesses may be associated specifically with symptoms of inattention-disorganization but not hyperactivity-impulsivity. Adults aged 18-37 (105 with ADHD, 90 controls) completed a neuropsychological battery. The ADHD group had weaker performance than did the control group (p<.01) on both executive and speed measures. Symptoms of inattention-disorganization were uniquely related to executive functioning with hyperactivity-impulsivity controlled. Inattention was associated with slower response speed, and hyperactivity-impulsivity with faster output speed. Results were not accounted for by IQ, age, gender, education level, or comorbid disorders. Findings are discussed in terms of developmental and dual-process models of ADHD leading into adulthood.

Die Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) im Erwachsenenalter

Zusammenfassung: Die ADHS ist eine häufige chronische Erkrankung des Kindes-, Jugend- und Erwachsenenalters. Die psychopathologische Kernsymptomatik besteht in allen Lebensaltern aus den Syndromen Aufmerksamkeitsstörung, Impulsivität und Hyperaktivität. Während Impulsivität und Hyperaktivität im Verlauf eine rückläufige Tendenz erkennen lassen oder einem Symptomwandel unterliegen, bleiben die Aufmerksamkeitsstörungen bei Erwachsenen oft unverändert und sind meist mit desorganisiertem Verhalten vergesellschaftet. Es sind spezielle diagnostische Kriterien für die Anwendung im Erwachsenenalter entwickelt worden. Sie ermöglichen zusammen mit den obligatorischen Diagnosekriterien nach DSM-IV oder ICD-10 eine ausreichend differenzierte Erfassung der Psychopathologie. Der Verlauf der ADHS ins Erwachsenenalter ist mit einer Fülle von gesundheitlichen Risiken, komorbiden Leiden und sozialen Gefährdungen belastet. Die Erforschung der Ursachen und pathogenetischen Abläufe hat gezeigt, dass es sich bei ADHS um ein genetisch besonders nachhaltig verankertes Störungsmuster handelt, das mit strukturellen und funktionellen zerebralen Auffälligkeiten und mit Dysfunktionen in zerebralen Transmitterfunktionen einhergeht.

The course of neuropsychological functions in children with attention deficit hyperactivity disorder from late childhood to early adolescence

OBJECTIVE

The aim of this follow-up study was to investigate the course of performance in attentional tasks in children with ADHD and normal controls in late childhood and preadolescence over short periods of time. The development of two dimensions of attention was compared: alertness/arousal and inhibitory control.

METHOD

Children with ADHD (N=28) and normal controls (N=25) were examined at three times: at baseline (age mean=10.8 years, SD=1.5), after one year (age mean=12.0 years, SD=1.6), and after 2.6 years (age mean=13.3 years, SD=1.6). They performed two tasks of a computerized battery for attentional performance: Alertness--a test of simple reaction time to visual stimuli contrasting a condition with and without auditory warning signal, and Incompatibility--a test of spatial interference/inhibitory control. Clinical diagnosis according to DSM-III-R criteria was established at time 1 and time 3 by structured diagnostic interviews.

RESULTS

In the Alertness task significant group differences regarding increased reaction time variability in ADHD, but not for reaction time itself, were found at time 1 and more pronounced at time 2. At time 3 group differences had disappeared. In the Incompatibility task group differences in number of errors were not observed at time 1, whereas children with ADHD made significantly more errors at time 2 and less pronounced at time 3. The degree of clinical symptom remission after 2.6 years was not related to changes in neuropsychological performance.

CONCLUSION

When measuring attentional functions, the selection of an appropriate time window seems to be essential for the detection of group differences between ADHD children and controls, because group differences are most pronounced before adolescence. The different developmental course of selective components of attention should be taken into account.

Attention deficit hyperactivity disorder and borderline personality disorder

To evaluate the association between attention deficit hyperactivity disorder (ADHD) and the diagnosis of borderline personality disorder (BPD) in adulthood, a systematic review of published follow-up data, mainly from observational studies was done. Electronic databases Medline, PsychInfo and PSYNDEXplus were searched from their earliest entries. All studies suggested significant relationships between ADHD and BPD. From a phenomenological point of view there seem to exist some similarities between these two disorders: deficits in affect regulation and impulse control, substance abuse, low self esteem and disturbed interpersonal relationship are common in both conditions. From a neuropsychological point of view dissociation in BPD might be regarded as a special form of behavioral inhibition and sustained attention comparable to ADHD. Possible therapeutic strategies of comorbid ADHD and BPD are discussed.

Self-report of ADHD symptoms in college students and repetition effects

The research in this article focuses on the relation between self-report of attention deficit disorder (ADD) symptoms and performance on a two-alternative forced-choice task that measures repetition effects. The ADD/Hyperactive Adolescent Self-Report Scale--Short Form is administered to college students after they completed the repetition effects task. Performance to familiar and novel stimuli can be measured using this paradigm. The results indicate that participants in the good and poor attention groups do not differ in their responses to repeated stimuli. However, participants who self-report poor attention are faster to respond to novel stimuli compared with participants who self-report good attention. This brief questionnaire appears to capture individual differences in attention and may be useful in attention research.

Neurocognitive effects of methylphenidate in adult attention-deficit/hyperactivity disorder

RATIONALE

Features of childhood attention-deficit/hyperactivity disorder (ADHD) often persist into adulthood. It has been shown that adult ADHD is associated with various neurocognitive deficits, including impairments in spatial working memory (SWM) and attention. It is not known whether these deficits are ameliorated by methylphenidate in adult ADHD.

OBJECTIVES

The aim of this study was to evaluate the neurocognitive effects of a single dose of methylphenidate on SWM, visual memory, spatial span and sustained attention in adult ADHD.

METHODS

Twenty-four adult patients, recruited from a specialised clinic for the assessment of adult ADHD, were entered into a double-blind, randomised, placebo-controlled crossover study using a single 30 mg dose of methylphenidate.

RESULTS

Eighteen patients met DSM-IV criteria for adult ADHD. Methylphenidate resulted in an improvement in SWM performance and sustained attention, together with a speeding in response time, in these patients. Six patients with attentional difficulties, who did not meet a DSM-IV diagnosis of ADHD, showed a different pattern of response to methylphenidate compared to the ADHD group. For the combined group, moderate correlations were shown between childhood ratings of ADHD (both self-reported and informant ratings) and response to methylphenidate on the SWM task.

CONCLUSIONS

Adults with ADHD had a similar neurocognitive response to methylphenidate to that previously reported for childhood ADHD. Our results provide further support for the validity of the ADHD syndrome as defined by DSM-IV and indicate possible neurocognitive substrates for clinical improvement with chronic methylphenidate.

Diagnostic issues for adolescents and adults with ADHD

Attention deficit hyperactivity disorder (ADHD) is a common childhood neuropsychiatric syndrome once thought to disappear with maturation. Current data indicate that ADHD remains "hidden" in many of the grown-ups who had it as children. Adult prevalence rates range from 1% to 6% of the population. Research suggests the core childhood symptoms of hyperactivity, inattention, and impulsivity shift with development, perhaps transforming into more overt difficulties in executive functions and affect regulation. ADHD is also usually nestled with other comorbid psychiatric conditions, especially in adolescents and adults, further complicating diagnosis and treatment. This article discusses how to recognize and diagnose ADHD in older patients. Key points include core symptoms present during childhood, appropriate family history in this strongly genetic condition, management of comorbidity, and the evolving role of diagnostic testing. Other medical causes for similar symptoms are considered.

The specificity of clinical characteristics in adults with attention-deficit/hyperactivity disorder: a comparison with patients with borderline personality disorder

Characteristics of DSM-IV attention-deficit/hyperactivity disorder (ADHD) in adults can also be found as part of other psychiatric disorders. This study investigated the specificity of adult ADHD features in relation to patients with borderline personality disorder (BPD), a syndrome which shares some of its intrinsic features with ADHD and often co-occurs with ADHD. A group of 20 adult patients selected on the basis of a diagnosis of ADHD and 20 patients selected on the basis of a diagnosis of BPD were assessed by the self-report Attention Deficit Scales for Adults (ADSA). The two groups were matched for age, verbal IQ and gender. Of the nine ADSA scales, seven showed significant inter-group differences, in particular involving attention, organisation and persistence. The 'Consistency/Long-Term' scale, which mainly reflects impaired task and goal persistence, was the best discriminator between the groups. Furthermore, ratings on this scale correlated significantly with the error score of a computer-administered task of spatial working memory, the performance of which has been reported to be impaired in patients with ADHD. The results provide further validation for the ADSA scales and support a previous claim that 'long-term consistencies', i.e., related to task and goal persistence, is 'the centrepiece behavioural issue' for adults with ADHD.

Impaired spatial working memory in adults with attention-deficit/hyperactivity disorder: comparisons with performance in adults with borderline personality disorder and in control subjects

OBJECTIVE

This study investigated a previous claim that working memory may be 'particularly impaired' in adult attention-deficit/hyperactivity disorder (ADHD), compared with other psychiatric disorders which affect frontal lobe-mediated executive functions.

METHOD

Performance on spatial working memory (SWM) and two additional tasks were investigated for adult patients selected on the basis of DSM-IV ADHD (n = 19), adult patients selected on the basis of borderline personality disorder (BPD) (n = 19), and non-clinical control subjects (n = 19). Groups were matched for age, verbal IQ and gender.

RESULTS

Analysis of variance showed that the ADHD group had significant impairment of SWM performance relative to the non-clinical controls. Although there was a trend towards impairment in the BPD group relative to non-clinical controls, this did not reach significance.

CONCLUSION

The results are consistent with the claim that aspects of working memory are 'particularly impaired' in adult ADHD. Also, the BPD group had a longer deliberation time for one of the additional tasks, compared with the ADHD group, which indicated that the patient groups may have different patterns of neuropsychological impairments.

Modafinil improves cognition and response inhibition in adult attention-deficit/hyperactivity disorder

BACKGROUND

Modafinil, a novel cognitive enhancer, has a clinical profile similar to conventional stimulants such as methylphenidate, despite a seemingly different mechanism of action. Modafinil selectively improves neuropsychological task performance in healthy volunteers, possibly through improved inhibitory control. We examined whether modafinil induced similar improvements in adults with attention-deficit/hyperactivity disorder.

METHODS

Twenty patients with a DSM-IV diagnosis of attention-deficit/hyperactivity disorder were entered into a double-blind, randomized, placebo-controlled crossover study using a single 200 mg dose of modafinil.

RESULTS

Modafinil produced a similar pattern of cognitive enhancement to that observed in healthy adults, with improvements on tests of short-term memory span, visual memory, spatial planning, and stop-signal motor inhibition. On several measures, increased accuracy was accompanied by slowed response latency. This alteration in the speed-accuracy trade-off may indicate that modafinil increases the ability to "reflect" on problems coupled with decreased impulsive responding. Improvements were also seen in sustained attention, which was unaffected in healthy subjects.

CONCLUSIONS

If these benefits are shown to be maintained with chronic administration, modafinil may have potential as an important therapy for attention-deficit/hyperactivity disorder with a similar effect to stimulants such as methylphenidate in improving stop-signal response inhibition but without the side effects commonly experienced with amphetamine-like drugs.

Developmental course of ADHD symptomatology during the transition from childhood to adolescence: a review with recommendations

Although historically conceptualized as a disorder that was limited to males during middle childhood, ADHD is currently conceptualized as a chronic disorder that persists into adolescence and adulthood for both sexes. Nonetheless, the veracity of adult ADHD continues to be the source of debate. In order to frame this debate, research leading to the conceptualization of ADHD as a chronic disorder is reviewed. A distinction is made between the developmental outcomes versus the developmental course of ADHD. It is concluded that although childhood ADHD is associated with negative developmental outcomes in adolescence and adulthood, questions about the developmental course of ADHD remain. Although it appears that ADHD diminishes with advancing age, a number of methodological limitations prohibit firm conclusions. Recommendations for future studies are made with an emphasis on 1) overcoming extant methodological limitations in the literature and 2) the need for theoretically derived hypotheses regarding continuity and change in ADHD symptomatology over time.