Differences in functional brain organization during gesture recognition between autistic and neurotypical individuals

Persons with and without autism process sensory information differently. Differences in sensory processing are directly relevant to social functioning and communicative abilities, which are known to be hampered in persons with autism. We collected functional magnetic resonance imaging data from 25 autistic individuals and 25 neurotypical individuals while they performed a silent gesture recognition task. We exploited brain network topology, a holistic quantification of how networks within the brain are organized to provide new insights into how visual communicative signals are processed in autistic and neurotypical individuals. Performing graph theoretical analysis, we calculated two network properties of the action observation network: 'local efficiency', as a measure of network segregation, and 'global efficiency', as a measure of network integration. We found that persons with autism and neurotypical persons differ in how the action observation network is organized. Persons with autism utilize a more clustered, local-processing-oriented network configuration (i.e. higher local efficiency) rather than the more integrative network organization seen in neurotypicals (i.e. higher global efficiency). These results shed new light on the complex interplay between social and sensory processing in autism.

Cognitive Functioning in Long-Term Benzodiazepine Users

BACKGROUND

Benzodiazepines are widely used in the treatment of anxiety disorders and sleep disturbances, but negative cognitive side effects have been reported after long-term use. Studies on the cognitive effects of long-term benzodiazepine use to date have typically included small samples and limited cognitive assessments.

OBJECTIVES

This study examined cognitive performance on four cognitive domains in long-term benzodiazepine users, compared to normative data. Furthermore, it was examined whether sex, age, benzodiazepine dose, and state and trait anxiety moderated cognitive functioning in long-term benzodiazepine users.

METHODS

Neuropsychological tests targeting different cognitive domains were administered to 92 patients with long-term benzodiazepine use who were accepted for enrolment into a benzodiazepine discontinuation programme in an academic hospital. Test scores were compared to a large normative data sample.

RESULTS

Of the long-term benzodiazepine users, 20.7% could be classified as cognitively impaired across all domains, with the largest effects found in the domains processing speed and sustained attention, and an overall worse performance in women, an effect which appears to be moderated by state anxiety. No effects of age or benzodiazepine dose were found.

CONCLUSIONS

These results extend those of earlier studies on benzodiazepine effects on specific cognitive domains. This study implies an overall detrimental cognitive effect in long-term benzodiazepine users rather than specific effects. Therefore, long-term benzodiazepine use should be avoided, and once present, tailored interventions aimed at tapering benzodiazepines are warranted.

Differences in the production and perception of communicative kinematics in autism

In human communication, social intentions and meaning are often revealed in the way we move. In this study, we investigate the flexibility of human communication in terms of kinematic modulation in a clinical population, namely, autistic individuals. The aim of this study was twofold: to assess (a) whether communicatively relevant kinematic features of gestures differ between autistic and neurotypical individuals, and (b) if autistic individuals use communicative kinematic modulation to support gesture recognition. We tested autistic and neurotypical individuals on a silent gesture production task and a gesture comprehension task. We measured movement during the gesture production task using a Kinect motion tracking device in order to determine if autistic individuals differed from neurotypical individuals in their gesture kinematics. For the gesture comprehension task, we assessed whether autistic individuals used communicatively relevant kinematic cues to support recognition. This was done by using stick-light figures as stimuli and testing for a correlation between the kinematics of these videos and recognition performance. We found that (a) silent gestures produced by autistic and neurotypical individuals differ in communicatively relevant kinematic features, such as the number of meaningful holds between movements, and (b) while autistic individuals are overall unimpaired at recognizing gestures, they processed repetition and complexity, measured as the amount of submovements perceived, differently than neurotypicals do. These findings highlight how subtle aspects of neurotypical behavior can be experienced differently by autistic individuals. They further demonstrate the relationship between movement kinematics and social interaction in high-functioning autistic individuals. LAY SUMMARY: Hand gestures are an important part of how we communicate, and the way that we move when gesturing can influence how easy a gesture is to understand. We studied how autistic and typical individuals produce and recognize hand gestures, and how this relates to movement characteristics. We found that autistic individuals moved differently when gesturing compared to typical individuals. In addition, while autistic individuals were not worse at recognizing gestures, they differed from typical individuals in how they interpreted certain movement characteristics.

Translation, Cross-Cultural Adaptation, and Validation of a Dutch Version of the Actions and Feelings Questionnaire in Autistic and Neurotypical Adults

The actions and feelings questionnaire (AFQ) provides a short, self-report measure of how well someone uses and understands visual communicative signals such as gestures. The objective of this study was to translate and cross-culturally adapt the AFQ into Dutch (AFQ-NL) and validate this new version in neurotypical and autistic populations. Translation and adaptation of the AFQ consisted of forward translation, synthesis, back translation, and expert review. In order to validate the AFQ-NL, we assessed convergent and divergent validity. We additionally assessed internal consistency using Cronbach’s alpha. Validation and reliability outcomes were all satisfactory. The AFQ-NL is a valid adaptation that can be used for both autistic and neurotypical populations in the Netherlands.

Is a Negative Attentional Bias in Individuals with Autism Spectrum Disorder Explained by Comorbid Depression? An Eye-Tracking Study

Heightened attention towards negative information is characteristic of depression. Evidence is emerging for a negative attentional bias in Autism spectrum disorder (ASD), perhaps driven by the high comorbidity between ASD and depression. We investigated whether ASD is characterised by a negative attentional bias and whether this can be explained by comorbid (sub) clinical depression. Participants (n = 116) with current (CD) or remitted depression (RD) and/or ASD, and 64 controls viewed positively and negatively valenced (non-)social pictures. Groups were compared on three components of visual attention using linear mixed models. Both CD individuals with and without ASD, but not remitted depressed and never-depressed ASD individuals showed a negative bias, suggesting that negative attentional bias might be a depressive state-specific marker for depression in ASD.

The Efficacy of Adapted MBCT on Core Symptoms and Executive Functioning in Adults With ADHD: A Preliminary Randomized Controlled Trial

OBJECTIVE

The aim of this study was to examine the effectiveness of mindfulness as a treatment for adults diagnosed with ADHD. A 12-week-adapted mindfulness-based cognitive therapy (MBCT) program is compared with a waiting list (WL) group.

METHOD

Adults with ADHD were randomly allocated to MBCT ( n = 55) or waitlist ( n = 48). Outcome measures included investigator-rated ADHD symptoms (primary), self-reported ADHD symptoms, executive functioning, depressive and anxiety symptoms, patient functioning, and mindfulness skills.

RESULTS

MBCT resulted in a significant reduction of ADHD symptoms, both investigator-rated and self-reported, based on per-protocol and intention-to-treat analyses. Significant improvements in executive functioning and mindfulness skills were found. Additional analyses suggested that the efficacy of MBCT in reducing ADHD symptoms and improving executive functioning is partially mediated by an increase in the mindfulness skill "Act With Awareness." No improvements were observed for depressive and anxiety symptoms, and patient functioning.

CONCLUSION

This study provides preliminary support for the effectiveness of MBCT for adults with ADHD.

Mindfulness-based cognitive therapy v. treatment as usual in adults with ADHD: a multicentre, single-blind, randomised controlled trial

BACKGROUND

There is a high need for evidence-based psychosocial treatments for adult attention-deficit hyperactivity disorder (ADHD) to offer alongside treatment as usual (TAU). Mindfulness-based cognitive therapy (MBCT) is a promising psychosocial treatment. This trial investigated the efficacy of MBCT + TAU v. TAU in reducing core symptoms in adults with ADHD.

METHODS

A multicentre, single-blind, randomised controlled trial (ClinicalTrials.gov: NCT02463396). Participants were randomly assigned to MBCT + TAU (n = 60), an 8-weekly group therapy including meditation exercises, psychoeducation and group discussions, or TAU only (n = 60), which reflected usual treatment in the Netherlands and included pharmacotherapy and/or psychoeducation. Primary outcome was ADHD symptoms rated by blinded clinicians. Secondary outcomes included self-reported ADHD symptoms, executive functioning, mindfulness skills, self-compassion, positive mental health and general functioning. Outcomes were assessed at baseline, post-treatment, 3- and 6-month follow-up. Post-treatment effects at group and individual level, and follow-up effects were examined.

RESULTS

In MBCT + TAU patients, a significant reduction of clinician-rated ADHD symptoms was found at post-treatment [M difference = -3.44 (-5.75, -1.11), p = 0.004, d = 0.41]. This effect was maintained until 6-month follow-up. More MBCT + TAU (27%) than TAU participants (4%) showed a ⩾30% reduction of ADHD symptoms (p = 0.001). MBCT + TAU patients compared with TAU patients also reported significant improvements in ADHD symptoms, mindfulness skills, self-compassion and positive mental health at post-treatment, which were maintained until 6-month follow-up. Although patients in MBCT + TAU compared with TAU reported no improvement in executive functioning at post-treatment, they did report improvement at 6-month follow-up.

CONCLUSIONS

MBCT might be a valuable treatment option alongside TAU for adult ADHD aimed at alleviating symptoms.

Similar Subgroups Based on Cognitive Performance Parse Heterogeneity in Adults With ADHD and Healthy Controls

OBJECTIVE

To characterize heterogeneity in adults with ADHD we aimed to identify subgroups within the adult ADHD spectrum, which differ in their cognitive profile.

METHOD

Neuropsychological data from adults with ADHD ( n = 133) and healthy control participants ( n = 132) were used in a confirmatory factor analysis. The resulting six cognitive factors were correlated across participants to form networks. We used a community detection algorithm to cluster these networks into subgroups.

RESULTS

Both the ADHD and control group separated into three profiles that differed in cognitive performance. Profile 1 was characterized by aberrant attention and inhibition, profile 2 by increased delay discounting, and profile 3 by atypical working memory and verbal fluency.

CONCLUSION

Our findings suggest that qualitative differences in neuropsychological performance exist in both control and ADHD adult individuals. This extends prior findings in children with and without ADHD and provides a framework to parse participants into well-defined subgroups.

fMRI Neurofeedback Training for Increasing Anterior Cingulate Cortex Activation in Adult Attention Deficit Hyperactivity Disorder. An Exploratory Randomized, Single-Blinded Study

Attention Deficit Hyperactivity Disorder (ADHD) is characterized by poor cognitive control/attention and hypofunctioning of the dorsal anterior cingulate cortex (dACC). In the current study, we investigated for the first time whether real-time fMRI neurofeedback (rt-fMRI) training targeted at increasing activation levels within dACC in adults with ADHD leads to a reduction of clinical symptoms and improved cognitive functioning. An exploratory randomized controlled treatment study with blinding of the participants was conducted. Participants with ADHD (n = 7 in the neurofeedback group, and n = 6 in the control group) attended four weekly MRI training sessions (60-min training time/session), during which they performed a mental calculation task at varying levels of difficulty, in order to learn how to up-regulate dACC activation. Only neurofeedback participants received continuous feedback information on actual brain activation levels within dACC. Before and after the training, ADHD symptoms and relevant cognitive functioning was assessed. Results showed that both groups achieved a significant increase in dACC activation levels over sessions. While there was no significant difference between the neurofeedback and control group in clinical outcome, neurofeedback participants showed stronger improvement on cognitive functioning. The current study demonstrates the general feasibility of the suggested rt-fMRI neurofeedback training approach as a potential novel treatment option for ADHD patients. Due to the study’s small sample size, potential clinical benefits need to be further investigated in future studies.

Trial Registration: ISRCTN12390961

Burden of illness and health care resource utilization in adult psychiatric outpatients with attention-deficit/hyperactivity disorder in Europe

OBJECTIVE

To assess the burden of illness and health care resource utilization of adult nonpsychotic psychiatric outpatients with attention-deficit/hyperactivity disorder (ADHD) in Europe.

METHODS

This was a multicountry, cross-sectional, observational study where unselected routine patients from clinical psychiatric outpatient settings were screened and assessed for ADHD. Patients were evaluated using the Clinical Global Impressions of Severity (CGI-S) scale, the Sheehan Disability Scale (SDS), and the EuroQol-5 Dimensions questionnaire. Data on comorbidities, functional impairment, and health care resource utilization were captured.

RESULTS

The study enrolled 2284 patients, of whom 1986 completed the study. The prevalence of ADHD was 17.4%, of whom 46.0% had a previous ADHD diagnosis. Patients with ADHD had a high clinical burden with psychiatric comorbidities, especially depression (43.0%) and anxiety disorders (36.4%). Substance abuse (9.2% vs. 3.4%) and alcohol abuse (10.3% vs. 5.2%) were more common in the ADHD cohort vs. the non-ADHD cohort. Only 11.5% of the patients with ADHD had no other psychiatric disorder. Various measures indicated a significantly poorer level of functioning for patients with ADHD than without ADHD, as indicated by higher scores for CGI-S (3.8 vs. 3.3) and SDS (18.9 vs. 11.6) and higher percentages of debt (35.5% vs. 24.3%) and criminality (13.8% vs. 6.1%). Lastly, the health care resource utilization was considerable and similar between adult psychiatric outpatients diagnosed and not diagnosed with ADHD.

CONCLUSIONS

Although care was taken when choosing the sites for this study, to make it representative of the general outpatient adult psychiatric population, caution should be advised in generalizing the findings of our study to the general ADHD or psychiatric outpatient population. This was an observational study, thus no inference on causality can be drawn. Having ADHD imposes a considerable health and social burden on patient and health care resource utilization comparable to other chronic psychiatric disorders.

Characterising resting-state functional connectivity in a large sample of adults with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a common childhood psychiatric disorder that often persists into adulthood. While several studies have identified altered functional connectivity in brain networks during rest in children with ADHD, few studies have been performed on adults with ADHD. Existing studies have generally investigated small samples. We therefore investigated aberrant functional connectivity in a large sample of adult patients with childhood-onset ADHD, using a data-driven, whole-brain approach. Adults with a clinical ADHD diagnosis (N=99) and healthy, adult comparison subjects (N=113) underwent a 9-minute resting-state fMRI session in a 1.5T MRI scanner. After elaborate preprocessing including a thorough head-motion correction procedure, group independent component analysis (ICA) was applied from which we identified six networks of interest: cerebellum, executive control, left and right frontoparietal and two default-mode networks. Participant-level network maps were obtained using dual-regression and tested for differences between patients with ADHD and controls using permutation testing. Patients showed significantly stronger connectivity in the anterior cingulate gyrus of the executive control network. Trends were also observed for stronger connectivity in the cerebellum network in ADHD patients compared to controls. However, there was considerable overlap in connectivity values between patients and controls, leading to relatively low effect sizes despite the large sample size. These effect sizes were slightly larger when testing for correlations between hyperactivity/impulsivity symptoms and connectivity strength in the executive control and cerebellum networks. This study provides important insights for studies on the neurobiology of adult ADHD; it shows that resting-state functional connectivity differences between adult patients and controls exist, but have smaller effect sizes than existing literature suggested.

Relationships Between Functional Outcomes and Symptomatic Improvement in Atomoxetine-Treated Adult Patients with Attention-Deficit/Hyperactivity Disorder: Post Hoc Analysis of an Integrated Database

BACKGROUND

Atomoxetine treatment is associated with improvements in functional outcomes in patients with attention-deficit/hyperactivity disorder (ADHD), although relationships between improvements in these outcomes and reductions in ADHD symptoms have not been comprehensively investigated in adults.

OBJECTIVES

The aim of this study was to assess relationships between functional outcomes and ADHD symptoms (primary objective), and to assess time courses of changes in functional outcomes from baseline to weeks 10 and 24 (secondary objective).

METHODS

We analyzed data pooled from seven Eli Lilly-sponsored placebo-controlled trials of atomoxetine in adults with ADHD that had Conners' Adult ADHD Rating Scales-Investigator Rated: Screening Version (CAARS-Inv:SV) total scores and functional outcome data at baseline and at week 10. Two trials also had these data at week 24. Patients were included in these pooled analyses if they had a CAARS-Inv:SV total score at baseline and at one or more post-baseline visits at weeks 10 or 24, or had post-baseline scores that would allow missing scores at weeks 10 or 24 to be imputed. To address the primary objective, changes in functional outcomes during treatment with atomoxetine versus placebo were assessed using last observation carried forward (LOCF) analysis of covariance (ANCOVA) and mixed-effects model repeated measures (MMRM) analysis, and correlations between score changes in CAARS-Inv:SV total and functional outcomes were assessed using Spearman's rank correlation coefficient (r) at weeks 10 and 24. The secondary objective was addressed using MMRM.

RESULTS

At baseline, patients generally had moderately severe or worse ADHD symptoms (based on CAARS-Inv:SV total scores) and impaired functional outcomes (based on Adult ADHD Quality-of-Life [AAQoL], Behavior Rating Inventory of Executive Function-Adult Version [BRIEF-A], Sheehan Disability Scale [SDS], and 36-item Short-Form Health Survey [SF-36] scores). These baseline characteristics were comparable in the atomoxetine and placebo groups. For atomoxetine versus placebo, statistically significant improvements were detected in AAQoL total and subscores at weeks 10 and 24, and in BRIEF-A Self-Report scores at week 10, but not in BRIEF-A Informant Report or SDS scores at week 10 (no BRIEF-A or SDS data were available at week 24), and not in SF-36 at weeks 10 or 24. All functional improvements were gradual. During treatment with atomoxetine, there were moderate correlations between reductions in CAARS-Inv:SV total scores and increases in AAQoL total and subscores at weeks 10 and 24 (r range -0.58 to -0.39; n = 394-545), and also with reductions in BRIEF-A Self-Report at week 10 (r = 0.49; n = 256). With placebo, moderate correlations were also found between reductions in CAARS-Inv:SV total scores and increases in AAQoL total and subscores at weeks 10 and 24 (r range -0.56 to -0.28; n = 321-542), and with reductions in BRIEF-A Self-Report at week 10 (r = 0.49; n = 271). However, correlations between changes in CAARS-Inv:SV and BRIEF-A Informant at week 10 were low for atomoxetine-treated patients (r = 0.25; n = 65), moderate with placebo (r = 0.42; n = 72), and there were low/no correlations between changes in CAARS-Inv:SV and functional outcome rating scales that are not specific to ADHD; that is, for atomoxetine-treated patients, SDS total r = 0.19 (n = 32 at week 10) and SF-36 r range - 0.20 to -0.01 (n = 51 at week 10, n = 183 at week 24).

CONCLUSIONS

Atomoxetine-treated adult patients experienced improvements in functional outcomes (AAQoL and BRIEF-A Self-Report) that correlated with reductions in ADHD symptoms. Although atomoxetine improved both the ADHD symptoms and functional outcomes, the correlation between symptoms and functional outcomes was low to moderate, suggesting that they measure overlapping but different aspects of the disorder. Hence, clinicians should assess not just ADHD symptoms, but also the functional impairments.

Enlarged striatal volume in adults with ADHD carrying the 9-6 haplotype of the dopamine transporter gene DAT1

The dopamine transporter gene, DAT1 (SLC6A3), has been studied extensively as a candidate gene for attention-deficit/hyperactivity disorder (ADHD). Different alleles of variable number of tandem repeats (VNTRs) in this gene have been associated with childhood ADHD (10/10 genotype and haplotype 10-6) and adult ADHD (haplotype 9-6). This suggests a differential association depending on age, and a role of DAT1 in modulating the ADHD phenotype over the lifespan. The DAT1 gene may mediate susceptibility to ADHD through effects on striatal volumes, where it is most highly expressed. In an attempt to clarify its mode of action, we examined the effect of three DAT1 alleles (10/10 genotype, and the haplotypes 10-6 and 9-6) on bilateral striatal volumes (nucleus accumbens, caudate nucleus, and putamen) derived from structural magnetic resonance imaging scans using automated tissue segmentation. Analyses were performed separately in three cohorts with cross-sectional MRI data, a childhood/adolescent sample (NeuroIMAGE, 301 patients with ADHD and 186 healthy participants) and two adult samples (IMpACT, 118 patients with ADHD and 111 healthy participants; BIG, 1718 healthy participants). Regression analyses revealed that in the IMpACT cohort, and not in the other cohorts, carriers of the DAT1 adult ADHD risk haplotype 9-6 had 5.9 % larger striatum volume relative to participants not carrying this haplotype. This effect varied by diagnostic status, with the risk haplotype affecting striatal volumes only in patients with ADHD. An explorative analysis in the cohorts combined (N = 2434) showed a significant gene-by-diagnosis-by-age interaction suggesting that carriership of the 9-6 haplotype predisposes to a slower age-related decay of striatal volume specific to the patient group. This study emphasizes the need of a lifespan approach in genetic studies of ADHD.

Deviant white matter structure in adults with attention-deficit/hyperactivity disorder points to aberrant myelination and affects neuropsychological performance

Attention-deficit/hyperactivity disorder (ADHD) in childhood is characterized by gray and white matter abnormalities in several brain areas. Considerably less is known about white matter microstructure in adults with ADHD and its relation with clinical symptoms and cognitive performance. In 107 adult ADHD patients and 109 gender-, age- and IQ-matched controls, we used diffusion tensor imaging (DTI) with tract-based spatial statistics (TBSS) to investigate whole-skeleton changes of fractional anisotropy (FA) and mean, axial, and radial diffusivity (MD, AD, RD). Additionally, we studied the relation of FA and MD values with symptom severity and cognitive performance on tasks measuring working memory, attention, inhibition, and delay discounting. In comparison to controls, participants with ADHD showed reduced FA in corpus callosum, bilateral corona radiata, and thalamic radiation. Higher MD and RD were found in overlapping and even more widespread areas in both hemispheres, also encompassing internal and external capsule, sagittal stratum, fornix, and superior lateral fasciculus. Values of FA and MD were not associated with symptom severity. However, within some white matter clusters that distinguished patients from controls, worse inhibition performance was associated with reduced FA and more impulsive decision making was associated with increased MD. This study shows widespread differences in white matter integrity between adults with persistent ADHD and healthy individuals. Changes in RD suggest aberrant myelination as a pathophysiological factor in persistent ADHD. The microstructural differences in adult ADHD may contribute to poor inhibition and greater impulsivity but appear to be independent of disease severity.

Cognitive heterogeneity in adult attention deficit/hyperactivity disorder: A systematic analysis of neuropsychological measurements

Attention Deficit/Hyperactivity Disorder (ADHD) in childhood is associated with impaired functioning in multiple cognitive domains: executive functioning (EF), reward and timing. Similar impairments have been described for adults with persistent ADHD, but an extensive investigation of neuropsychological functioning in a large sample of adult patients is currently lacking. We systematically examined neuropsychological performance on tasks measuring EF, delay discounting, time estimation and response variability using univariate ANCOVA's comparing patients with persistent ADHD (N=133, 42% male, mean age 36) and healthy adults (N=132, 40% male, mean age 36). In addition, we tested which combination of variables provided the highest accuracy in predicting ADHD diagnosis. We also estimated for each individual the severity of neuropsychological dysfunctioning. Lastly, we investigated potential effects of stimulant medication and a history of comorbid major depressive disorder (MDD) on performance. Compared to healthy adults, patients with ADHD showed impaired EF, were more impulsive, and more variable in responding. However, effect sizes were small to moderate (range: 0.05-0.70) and 11% of patients did not show neuropsychological dysfunctioning. The best fitting model predicting ADHD included measures from distinct cognitive domains (82.1% specificity, 64.9% sensitivity). Furthermore, patients receiving stimulant medication or with a history of MDD were not distinctively impaired. To conclude, while adults with ADHD as a group are impaired on several cognitive domains, the results confirm that adult ADHD is neuropsychologically heterogeneous. This provides a starting point to investigate individual differences in terms of impaired cognitive pathways.

Lower white matter microstructure in the superior longitudinal fasciculus is associated with increased response time variability in adults with attention-deficit/ hyperactivity disorder

BACKGROUND

Response time variability (RTV) is consistently increased in patients with attention-deficit/hyperactivity disorder (ADHD). A right-hemispheric frontoparietal attention network model has been implicated in these patients. The 3 main connecting fibre tracts in this network, the superior longitudinal fasciculus (SLF), inferior longitudinal fasciculus (ILF) and the cingulum bundle (CB), show microstructural abnormalities in patients with ADHD. We hypothesized that the microstructural integrity of the 3 white matter tracts of this network are associated with ADHD and RTV.

METHODS

We examined RTV in adults with ADHD by modelling the reaction time distribution as an exponentially modified Gaussian (ex-Gaussian) function with the parameters μ, σ and τ, the latter of which has been attributed to lapses of attention. We assessed adults with ADHD and healthy controls using a sustained attention task. Diffusion tensor imaging-derived fractional anisotropy (FA) values were determined to quantify bilateral microstructural integrity of the tracts of interest.

RESULTS

We included 100 adults with ADHD and 96 controls in our study. Increased τ was associated with ADHD diagnosis and was linked to symptoms of inattention. An inverse correlation of τ with mean FA was seen in the right SLF of patients with ADHD, but no direct association between the mean FA of the 6 regions of interest with ADHD could be observed.

LIMITATIONS

Regions of interest were defined a priori based on the attentional network model for ADHD and thus we might have missed effects in other networks.

CONCLUSION

This study suggests that reduced microstructural integrity of the right SLF is associated with elevated τ in patients with ADHD.

Processing of emotion words by patients with autism spectrum disorders: evidence from reaction times and EEG

This study investigated processing of emotion words in autism spectrum disorders (ASD) using reaction times and event-related potentials (ERP). Adults with (n = 21) and without (n = 20) ASD performed a lexical decision task on emotion and neutral words while their brain activity was recorded. Both groups showed faster responses to emotion words compared to neutral, suggesting intact early processing of emotion in ASD. In the ERPs, the control group showed a typical late positive component (LPC) at 400-600 ms for emotion words compared to neutral, while the ASD group showed no LPC. The between-group difference in LPC amplitude was significant, suggesting that emotion words were processed differently by individuals with ASD, although their behavioral performance was similar to that of typical individuals.

Predictive validity of self-report questionnaires in the assessment of autism spectrum disorders in adults

While various screening instruments for autism spectrum disorders are widely used in diagnostic assessments, their psychometric properties have not been simultaneously evaluated in the outpatient setting where these instruments are used most. In this study, we tested the Ritvo Autism Asperger Diagnostic Scale–Revised and two short versions of the Autism-Spectrum Quotient, the AQ-28 and AQ-10, in 210 patients referred for autism spectrum disorder assessment and in 63 controls. Of the 210 patients, 139 received an autism spectrum disorder diagnosis and 71 received another psychiatric diagnosis. The positive predictive values indicate that these tests correctly identified autism spectrum disorder patients in almost 80% of the referred cases. However, the negative predictive values suggest that only half of the referred patients without autism spectrum disorder were correctly identified. The sensitivity and specificity of each of these instruments were much lower than the values reported in the literature. In this study, the sensitivity of the Ritvo Autism Asperger Diagnostic Scale–Revised was the highest (73%), and the Autism-Spectrum Quotient short forms had the highest specificity (70% and 72%). Based on the similar area under the curve values, there is no clear preference for any of the three instruments. None of these instruments have sufficient validity to reliably predict a diagnosis of autism spectrum disorder in outpatient settings.

Brain alterations in adult ADHD: effects of gender, treatment and comorbid depression

Children with attention-deficit/hyperactivity disorder (ADHD) have smaller volumes of total brain matter and subcortical regions, but it is unclear whether these represent delayed maturation or persist into adulthood. We performed a structural MRI study in 119 adult ADHD patients and 107 controls and investigated total gray and white matter and volumes of accumbens, caudate, globus pallidus, putamen, thalamus, amygdala and hippocampus. Additionally, we investigated effects of gender, stimulant treatment and history of major depression (MDD). There was no main effect of ADHD on the volumetric measures, nor was any effect observed in a secondary voxel-based morphometry (VBM) analysis of the entire brain. However, in the volumetric analysis a significant gender by diagnosis interaction was found for caudate volume. Male patients showed reduced right caudate volume compared to male controls, and caudate volume correlated with hyperactive/impulsive symptoms. Furthermore, patients using stimulant treatment had a smaller right hippocampus volume compared to medication-naïve patients and controls. ADHD patients with previous MDD showed smaller hippocampus volume compared to ADHD patients with no MDD. While these data were obtained in a cross-sectional sample and need to be replicated in a longitudinal study, the findings suggest that developmental brain differences in ADHD largely normalize in adulthood. Reduced caudate volume in male patients may point to distinct neurobiological deficits underlying ADHD in the two genders. Smaller hippocampus volume in ADHD patients with previous MDD is consistent with neurobiological alterations observed in MDD.

[Feasibility and effectiveness of mindfulness training in adults with ADHD: a pilot study]

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is a developmental disorder that often continues into adulthood. Stimulant medication is the common treatment for ADHD. However, there is a need for psychosocial interventions in addition to medication.

AIM

To conduct a pilot study which examines the feasibility and effectiveness of mindfulness training for adults with ADHD.

METHOD

Eleven adults with ADHD participated in a mindfulness training scheme lasting 10 weeks. ADHD symptoms, anxiety and depressive symptoms, quality of life, mindfulness skills and attentional tasks were measured before and after the period of mindfulness training.

RESULTS

Nine participants completed the mindfulness training and were satisfied with the training. Eight of these reported improvement in their ADHD symptoms. For all participants, their quality of life, awareness of their actions and executive control had also improved.

CONCLUSION

Mindfulness is a feasible treatment strategy for adults with ADHD and seems to have a positive effect on ADHD symptoms and executive control.

Atypical vertical sound localization and sound-onset sensitivity in people with autism spectrum disorders

BACKGROUND

Autism spectrum disorders (ASDs) are associated with auditory hyper- or hyposensitivity; atypicalities in central auditory processes, such as speech-processing and selective auditory attention; and neural connectivity deficits. We sought to investigate whether the low-level integrative processes underlying sound localization and spatial discrimination are affected in ASDs.

METHODS

We performed 3 behavioural experiments to probe different connecting neural pathways: 1) horizontal and vertical localization of auditory stimuli in a noisy background, 2) vertical localization of repetitive frequency sweeps and 3) discrimination of horizontally separated sound stimuli with a short onset difference (precedence effect).

RESULTS

Ten adult participants with ASDs and 10 healthy control listeners participated in experiments 1 and 3; sample sizes for experiment 2 were 18 adults with ASDs and 19 controls. Horizontal localization was unaffected, but vertical localization performance was significantly worse in participants with ASDs. The temporal window for the precedence effect was shorter in participants with ASDs than in controls.

LIMITATIONS

The study was performed with adult participants and hence does not provide insight into the developmental aspects of auditory processing in individuals with ASDs.

CONCLUSION

Changes in low-level auditory processing could underlie degraded performance in vertical localization, which would be in agreement with recently reported changes in the neuroanatomy of the auditory brainstem in individuals with ASDs. The results are further discussed in the context of theories about abnormal brain connectivity in individuals with ASDs.

Shared and unique genetic contributions to attention deficit/hyperactivity disorder and substance use disorders: a pilot study of six candidate genes

The shared genetic basis of attention deficit/hyperactivity disorder (ADHD) and substance use disorders (SUDs) was explored by investigating the association of candidate risk factors in neurotransmitter genes with both disorders. One hundred seven methadone maintenance treatment patients, 36 having an ADHD diagnosis, 176 adult patients with ADHD without SUDs, and 500 healthy controls were genotyped for variants in the DRD4 (exon 3 VNTR), DRD5 (upstream VNTR), HTR1B (rs6296), DBH (rs2519152), COMT (rs4680; Val158Met), and OPRM1 (rs1799971; 118A>G) genes. Association with disease was tested using logistic regression models. This pilot study was adequately powered to detect larger genetic effects (OR≥2) of risk alleles with a low frequency. Compared to controls, ADHD patients (with and without SUDs) showed significantly increased frequency of the DBH (rs2519152: OR 1.73; CI 1.15-2.59; P=0.008) and the OPRM1 risk genotypes (rs1799971: OR 1.71; CI 1.17-2.50; P=0.006). The DBH risk genotype was associated with ADHD diagnosis, with the association strongest in the pure ADHD group. The OPRM1 risk genotype increased the risk for the combined ADHD and SUD phenotype. The present study strengthens the evidence for a shared genetic basis for ADHD and addiction. The association of OPRM1 with the ADHD and SUD combination could help to explain the contradictory results of previous studies. The power limitations of the study restrict the significance of these findings: replication in larger samples is warranted.

Symptomatic overlap between attention-deficit/hyperactivity disorder and borderline personality disorder in women: the role of temperament and character traits

OBJECTIVE

There is substantial symptomatic overlap between attention-deficit/hyperactivity disorder (ADHD) and borderline personality disorder (BPD) in adults, but the nature of the relationship between these disorders needs further clarification. The role of temperament and character traits in the differentiation of classes of patients with similar ADHD and BPD symptom profiles was examined and possible pathways between early temperament and future ADHD and/or BPD were hypothesized.

METHODS

Structured diagnostic interviews were conducted in 103 female patients to assess current Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition symptoms of ADHD and BPD, and parent interviews were used to assess ADHD symptoms in childhood. Classes of subjects with homogeneous symptom profiles were identified using latent class analysis. Temperament and character traits were assessed using the Temperament and Character Inventory of Cloninger et al; scores were then compared across the latent classes.

RESULTS

Latent class analysis revealed 4 mutually exclusive classes of patients: 1 with only ADHD symptoms; 1 with BPD symptoms and ADHD symptoms of hyperactivity; 1 with BPD symptoms and ADHD symptoms of inattention, hyperactivity, and impulsivity; and 1 with BPD symptoms and ADHD symptoms of inattention and hyperactivity. High Novelty Seeking was found in all classes except for the class with symptoms of BPD and only the hyperactivity aspect of ADHD. The highest Novelty Seeking temperament scores were found in that class of patients with both symptoms of BPD and symptoms in all areas of ADHD. High Harm Avoidance, low Cooperativeness, and low Self-directedness were specifically related to classes containing BPD symptoms.

CONCLUSIONS

Classes of ADHD and BPD symptoms are associated with specific temperament and character configurations. Novelty Seeking was associated with the inattention symptoms of ADHD. An outspoken Novelty Seeking temperament suggests vulnerability for the development of ADHD and co-occurring BPD. Contrary to patients with combined ADHD and BPD symptoms, patients with only symptoms of ADHD showed normal character development and thus an absence of a personality disorder. Assessment of temperament and character traits can improve our understanding of the complex relationship between ADHD and BPD.

Common variants in the TPH1 and TPH2 regions are not associated with persistent ADHD in a combined sample of 1,636 adult cases and 1,923 controls from four European populations

The tryptophan hydroxylase 1 and 2 (TPH1 and TPH2) genes encode the rate-limiting enzymes in the serotonin biosynthesis. Genetic variants in both genes have been implicated in several psychiatric disorders. For attention-deficit/hyperactivity disorder (ADHD) in children, the results are conflicting, and little is known about their role in adult ADHD patients. We therefore first genotype-tagged all common variants within both genes in a Norwegian sample of 451 patients with a diagnosis of adult ADHD and 584 controls. Six of the single nucleotide polymorphisms (SNPs) were subsequently genotyped in three additional independent European Caucasian samples of adult ADHD cases and controls from the International Multicenter persistent ADHD Collaboration (IMpACT). None of the SNPs reached formal study-wide significance in the total meta-analysis sample of 1,636 cases and 1,923 controls, despite having a power of >80% to detect a variant conferring an OR = 1.25 at P = 0.001 level. Only the TPH1 SNP rs17794760 showed nominal significance [OR = 0.84 (0.71-1.00), P = 0.05]. In conclusion, in the single largest ADHD genetic study of TPH1 and TPH2 variants presented to date (n = 3,559 individuals), we did not find consistent evidence for a substantial effect of common genetic variants on persistent ADHD.

Rainwater harvesting in schools in Taiwan: system characteristics and water quality

In order to understand the current status of rainwater harvesting (RWH) practices in Taiwan's schools, a study was carried out to examine the RWH system performance, water usage, and water quality in these sites. A total of 29 schools in various regions were selected for this investigation, including 7 in the northern, 7 in the central, 8 in the southern, and 7 in the eastern regions of Taiwan. Water quality indicators tested were: pH, temperature, conductivity, oxidation-reduction potential, suspended solid, total organic carbon, fecal coliform, and total coliform. From this study, it was found that RWH systems in these sites generally had two different designs: one that collected rainwater only, and one that collected both rainwater and grey water. From statistical analysis, it was found that water quality indicators such as suspended solids, total organic carbon, and fecal coliform were significantly affected by the water source and site location. Fecal coliforms in most of the sites we studied were high and not qualified for toilet flushing. The average water retention time of 2.4 months was long and considered to be the main reason to cause high fecal coliform counts. Finally, the benefit analysis was conducted to evaluate economic feasibility of rainwater harvesting for these schools. It turned out that 20% of them were able to gain economic benefits from using rainwater.

Removal of manganese ions from synthetic groundwater by oxidation using KMnO(4) and the characterization of produced MnO(2) particles

The aim of this study is to investigate the conditions for the removal of manganese ions from synthetic groundwater by oxidation using KMnO(4) to keep the concentration below the allowed level (0.05 mg/L). The process includes low-level aeration and addition of KMnO(4) in a Jar test system with Mn(2 + ) concentration of 0.50 mg/L, similar to that of natural groundwater in Taiwan. Different parameters such us aeration-pH, oxidant dose, and stirring speed were studied. Aeration alone was not sufficient to remove Mn(2 + ) ions completely even when the pH was increased. When a stoichiometric amount of KMnO(4) (0.96 mg/L) was used, a complete Mn(2 + ) removal was achieved within 15 min at an optimum pH of 8.0. As the amount of KMnO(4) was doubled, lower removal efficiency was obtained because the oxidant also generated manganese ions. The removal of Mn(2 + ) ions could be completed at pH 9.0 using an oxidant dose of 0.48 mg/L because Mn(2 + ) could be sorbed onto the MnO(2) particles. Finally, The MnO(2) particles were characterized using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX).

Neural correlates of pragmatic language comprehension in autism spectrum disorders

Difficulties with pragmatic aspects of communication are universal across individuals with autism spectrum disorders (ASDs). Here we focused on an aspect of pragmatic language comprehension that is relevant to social interaction in daily life: the integration of speaker characteristics inferred from the voice with the content of a message. Using functional magnetic resonance imaging (fMRI), we examined the neural correlates of the integration of voice-based inferences about the speaker's age, gender or social background, and sentence content in adults with ASD and matched control participants. Relative to the control group, the ASD group showed increased activation in right inferior frontal gyrus (RIFG; Brodmann area 47) for speaker-incongruent sentences compared to speaker-congruent sentences. Given that both groups performed behaviourally at a similar level on a debriefing interview outside the scanner, the increased activation in RIFG for the ASD group was interpreted as being compensatory in nature. It presumably reflects spill-over processing from the language dominant left hemisphere due to higher task demands faced by the participants with ASD when integrating speaker characteristics and the content of a spoken sentence. Furthermore, only the control group showed decreased activation for speaker-incongruent relative to speaker-congruent sentences in right ventral medial prefrontal cortex (vMPFC; Brodmann area 10), including right anterior cingulate cortex (ACC; Brodmann area 24/32). Since vMPFC is involved in self-referential processing related to judgments and inferences about self and others, the absence of such a modulation in vMPFC activation in the ASD group possibly points to atypical default self-referential mental activity in ASD. Our results show that in ASD compensatory mechanisms are necessary in implicit, low-level inferential processes in spoken language understanding. This indicates that pragmatic language problems in ASD are not restricted to high-level inferential processes, but encompass the most basic aspects of pragmatic language processing.

Association of the dopamine transporter (SLC6A3/DAT1) gene 9-6 haplotype with adult ADHD

ADHD is a neuropsychiatric disorder characterized by chronic hyperactivity, inattention and impulsivity, which affects about 5% of school-age children. ADHD persists into adulthood in at least 15% of cases. It is highly heritable and familial influences seem strongest for ADHD persisting into adulthood. However, most of the genetic research in ADHD has been carried out in children with the disorder. The gene that has received most attention in ADHD genetics is SLC6A3/DAT1 encoding the dopamine transporter. In the current study we attempted to replicate in adults with ADHD the reported association of a 10-6 SLC6A3-haplotype, formed by the 10-repeat allele of the variable number of tandem repeat (VNTR) polymorphism in the 3' untranslated region of the gene and the 6-repeat allele of the VNTR in intron 8 of the gene, with childhood ADHD. In addition, we wished to explore the role of a recently described VNTR in intron 3 of the gene. Two hundred sixteen patients and 528 controls were included in the study. We found a 9-6 SLC6A3-haplotype, rather than the 10-6 haplotype, to be associated with ADHD in adults. The intron 3 VNTR showed no association with adult ADHD. Our findings converge with earlier reports and suggest that age is an important factor to be taken into account when assessing the association of SLC6A3 with ADHD. If confirmed in other studies, the differential association of the gene with ADHD in children and in adults might imply that SLC6A3 plays a role in modulating the ADHD phenotype, rather than causing it.

[Autism spectrum disorders in adults]

Early infantile autism' as defined by Kanner has grown into a spectrum of autistic disorders. The recognition of Asperger's disorder and of pervasive developmental disorder not otherwise specified (PDD-NOS), has led to increased demand for appropriate diagnostic assessment of autism in adults. The expression ofimpairments in social interaction, communication, imagination and mental flexibility changes during development into adulthood. The diagnostic procedure in adult psychiatry should comprise a collateral developmental interview. Autism spectrum disorders in adults may mimic, or be overshadowed by, other psychiatric disorders. For effective diagnosis, the application of structured interviews, such as the 'Autism diagnostic observation schedule' (ADOS), 'Autism diagnostic interview-revised' (ADI-R) or 'Diagnostic interview for social and communication disorders' (DISCO) is recommended.

The role of craving in relapse after discontinuation of long-term benzodiazepine use

OBJECTIVE

Craving for benzodiazepines has never been examined as a factor of relapse after successful benzodiazepine discontinuation. In this study, we examined the predictive value of craving on benzodiazepine relapse.

METHOD

A stepped-care intervention trial aimed to discontinue long-term benzodiazepine use in general practice. The first step was the sending of a letter to users advising them to gradually quit their use by themselves (i.e., minimal intervention). The second step, a supervised tapering-off program, was offered to those unable to discontinue by themselves. Craving was assessed by means of the Benzodiazepine Craving Questionnaire (BCQ). Multiple Cox proportional hazards regression analyses were performed to examine the effect of craving on subsequent relapse during a 15-month follow-up period in patients who had successfully quit their benzodiazepine use by themselves after the minimal intervention (N = 79) and in those patients who had successfully quit after the supervised tapering-off program (N = 45). Data were collected from August 1998 to December 2001.

RESULTS

Thirty-five (44%) and 24 (53%) patients had relapsed after the minimal intervention and tapering-off program, respectively. Patients able to quit by themselves experienced very little craving. In this sample, craving was not related to relapse (p = .82). In patients who needed an additional supervised tapering-off program, higher craving scores were significantly related to relapse (hazard ratio = 1.26, 95% CI = 1.02 to 1.54, p = .029), when corrected for benzodiazepine characteristics, psychopathology, and personality characteristics.

CONCLUSION

Craving is an independent factor of subsequent relapse after successful benzodiazepine discontinuation in long-term benzodiazepine users who are not able to quit their usage of their own accord.

The absence of benzodiazepine craving in a general practice benzodiazepine discontinuation trial

This study aimed to assess benzodiazepine craving longitudinally and to describe its time course by means of the Benzodiazepine Craving Questionnaire (BCQ). Subjects were long-term benzodiazepine users participating in a two-part treatment intervention aimed to reduce long-term benzodiazepine use in general practice in The Netherlands. Four repeated measurements of benzodiazepine craving were taken over a 21-month follow-up period. Results indicated that (1) benzodiazepine craving severity decreased over time, (2) patients still using benzodiazepines experienced significantly more severe craving than patients who had quit their use after one of the two interventions, and (3) the way in which patients had attempted to quit did not influence the experienced craving severity over time, however, (4) patients who had received additional tapering off, on average, reported significantly more severe craving than patients who had only received a letter as an incentive to quit. Although benzodiazepine craving is prevalent among (former) long-term benzodiazepine users during and after discontinuation, craving severity decreases over time to negligible proportions. Self-reported craving can be longitudinally monitored and quantified by means of the BCQ.

[Short- and long-term results of a systematic benzodiazepine discontinuation programme for psychiatric patients]

BACKGROUND

Although guidelines for the use of benzodiazepines emphasise that these drugs should only be prescribedfor short periods of time, in practice long-term usage persists and can be a serious problem. There is afear among patients and among doctors prescribing the drugs that symptoms will become more acute if attempts are made to terminate the regimen.

AIM

To determine the short- and long-term results of a standardized method for discontinuing the use of benzodiazepines (BZD) and to test whether these results were related to the age and gender of the patients, the BZD dosage level and the treatment modality.

METHOD

A retrospective cohort study was performed at the Department of Psychiatry of the Radboud University Nijmegen Medical Centre. A systematic BZD discontinuation programme was offered by the Department of Psychiatry to patients who had been using BZD for at least three months. By studying the medical records, by conducting telephone interviews and by examining the prescription data of the GP or the pharmacy it was ascertained how many patients managed to become abstinent in the short- and long-term.

RESULTS

Upon termination of the discontinuation programme 65% of the patients had managed to stop taking BZD and at follow-up approximately 2 years later 37% of the patients interviewed had not used BZD for the last 3 months. Neither age, nor gender, nor treatment modality predicted BZD usage immediately after the end of the discontinuation programme or at the 2-year follow-up. A high dose of BZD was the only significant predictor of post-programme usage 2 years later.

CONCLUSION

A systematic discontinuation programme seems to be just as effective for psychiatric patients as it isfor general practice patients and deserves to be included in the regular treatment programmes provided by psychiatric practices.

[Predicting the success of a benzodiazepine discontinuation programme: myths or clinical wisdom?]

BACKGROUND

After successful completion of a benzodiazepine withdrawal programme it nevertheless is hard to remain abstinent in the long term.

AIM

To determine to what extent the success of a benzodiazepine discontinuation programme for psychiatric patients with chronic benzodiazepine use (> or = 3 months) can be predicted from the severity of the anxiety, sleep disorders and depressive symptoms, and from the level of benzodiazepine dependence. The predictive values of coping style and personality characteristics were also studied.

METHOD

A prognostic cohort study with patients of the Radboud University Nijmegen Medical Centre was conducted. Before entering the programme 92 patients were given a psychological assessment. Anxiety level, benzodiazepine dependence, coping style and personality traits were measured by means of psychological questionnaires. The DSM-IV axis I classification for each patient was known. Patients who had stopped their medication immediately after the discontinuation programme ended (n = 6o) were compared with patients who had not been successful in completing the programme (n = 32). Thereafter, patients who were still abstinent at the follow-up about 2 years later (n = 25) were compared with patients who at that time /used benzodiazepine (n = 43).

RESULTS

Of all the variables examined, it was only a specific coping style whereby patients expressed their (negative) emotions which was associated with the short- and long-term success of the discontinuation programme. The more patients expressed their negative emotions, the greater the chance of a successful outcome and permanent abstinence. Coping style, however, predicted for only a small proportion of the variance in the success of the discontinuation programme.

CONCLUSION

The psychological characteristics and the DSM-IV axis I classifications should not exert undue influence on the clinician's decision to advise the patient to stop or continue taking benzodiazepines.

Determination of the main risk factors for benzodiazepine dependence using a multivariate and multidimensional approach

The aim of this study was to identify risk factors for benzodiazepine (BZD) dependence, such as sociodemographic variables, characteristics of BZD use, and psychiatric parameters, which to date have been found to relate inconsistently to indicators of BZD dependence such as chronic BZD use and BZD withdrawal symptoms. The Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ), Schedules for Clinical Assessment in Neuropsychiatry (SCAN), and Symptom Checklist-90 (SCL-90) were administered to 599 outpatients using BZDs. Regression analyses were conducted using BZD dependence diagnoses and severity scales as dependent variables. BZD dependence diagnoses were only predicted by being a self-help patient and long BZD elimination half-life (for only the DSM-III-R). The main predictors of BZD dependence severity, as measured by the ICD-10, DSM-III-R scales, and Bendep-SRQ Rasch scales, were in decreasing order: (1) being a self-help patient; (2) higher BZD dose, longer duration of BZD use, younger age; and (3) non-native cultural origin, lower level of education, being in outpatient treatment for alcohol and/or drug dependence, and the interaction of BZD dose with duration of BZD use. We conclude that a limited number of recognizable risk factors appear to predict the severity of BZD dependence. Additional administration of a specific BZD dependence instrument is recommended to confirm suspected BZD dependence and guide further clinical decision-making.

Dependence potential of antidepressants compared to benzodiazepines

The aim of the present study was to compare the possible dependence potential of antidepressants (ADs) to benzodiazepines (BZDs). The Schedules for Clinical Assessment in Neuropsychiatry (SCAN), the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ) and the Symptom Checklist-90 (SCL-90) were administered to 70 psychiatric outpatient BZD users and 54 psychiatric outpatient AD users. Significantly more Diagnostic and Statistical Manual of Mental Disorders, Third Edition Revised (DSM-III-R) as well as International Classification of Diseases, Tenth Edition (ICD-10) past year (PY) and lifetime (LT) dependence diagnoses were made in the BZD group than in the AD group. Bendep-SRQ scale scores for Problematic Use, Preoccupation and Lack of Compliance were significantly higher in the BZD group than in the AD group. The BZD group also had a higher rating on the Withdrawal scale, but this difference was not statistically significant. According to DSM-III-R and ICD-10 criteria ADs do have some dependence liability in psychiatric outpatients, but clearly to a lesser extent than BZDs. Further research is needed to differentiate the dependence potential among the various classes of ADs.

Latent trait standardization of the benzodiazepine dependence self-report questionnaire using the Rasch scaling model

The aim of the present study was to obtain standardized scores that correspond with the raw scores on the four Rasch scales of the Benzodiazepine Dependence-Self Report Questionnaire (Bendep-SRQ). The eligible normative group for standardization of the Bendep-SRQ scales consisted of 217 general practice (GP) patients, all using benzodiazepines. Two standardization methods were used and compared: "classical standardization," which transforms raw scores into standard scores on the unit normal distribution, and "latent trait standardization," which transforms raw scores into latent trait scores. The latter requires the Rasch model with the additional assumption of a normally distributed latent trait, which held true for the scales "problematic use," "lack of compliance," and "withdrawal," but not for "preoccupation." The observed unequal item spacing on the "preoccupation" scale was hypothesized to induce a response tendency of nondeviation, causing a local violation of the assumption of a normally distributed latent trait. Nevertheless, comparison of the results of the two standardization methods revealed such a high degree of resemblance, that latent trait standardization could be used for "preoccupation" just as well as classical standardization. The presented standard scores and corresponding percentile ranks make raw Bendep-SRQ scores clinically interpretable in relation to the normative GP sample. Incorporation of the Rasch scaling methodology into the development of the Bendep-SRQ marks the adoption of the item response theory in the field of applied test methodology. In this process, it appears that equal item spacing has to be taken into account to prevent local violations of the Rasch model with the additional assumption of a normally distributed latent trait.

Cross-validation of the benzodiazepine dependence self-report questionnaire in outpatient benzodiazepine users

The aim of this study was to cross-validate the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ), which reflects the severity of benzodiazepine (BZD) dependence. The Bendep-SRQ, Symptom Checklist-90 (SCL-90) Schedules for Clinical Assessments in Neuropsychiatry (SCAN), and Addiction Severity Index-Revised (ASI-R) were administered to 102 general practice (GP) patients and 126 psychiatric outpatients who were using BZDs. The scalability and reliability of the Bendep-SRQ scales were reassessed in terms of Rasch homogeneity, subject discriminability, item discriminability, and test-retest stability. Present and original Rasch item orders were compared to evaluate construct validity. A matrix of all measures was factor-analyzed to assess concurrent and discriminant validity. The scalability of the Bendep-SRQ scales was confirmed. The reliability results were fairly good. Present and original Rasch item orders corresponded. The Bendep-SRQ scales and concurrent measures had high loadings on one factor, the discriminant measures on two other factors. In spite of some differences with respect to sociodemographic characteristics and pattern of BZD use, the cross-validation results agreed well with the results of the original study on the Bendep-SRQ. The Bendep-SRQ has presently acquired enough support of favorable and consistent results for clinical and scientific use.

Assessment of benzodiazepine dependence in alcohol and drug dependent outpatients: a research report

In this study on 99 outpatients who were being treated for alcohol and/or drug dependence and also using benzodiazepines (BZDs), prevalence rates of DSM-III-R and ICD-10 substance dependence diagnoses were ascertained and scalability, reliability and validity of the scales of the Benzodiaepine Dependence Self-Report Questionnaire (Bendep-SRQ) were assessed. The latter properties were investigated by Rasch analyses, discriminability coefficients, test-retest coefficients and factor analyses. BZD dependence was found to be a prevalent additional diagnosis. The psychometric findings appear to support the use of the Bendep-SRQ at outpatient addiction centers, which could contribute to a more differentiated treatment for poly-substance dependence.

The 1.7 A crystal structure of human cell cycle checkpoint kinase Chk1: implications for Chk1 regulation

The checkpoint kinase Chk1 is an important mediator of cell cycle arrest following DNA damage. The 1.7 A resolution crystal structures of the human Chk1 kinase domain and its binary complex with an ATP analog has revealed an identical open kinase conformation. The secondary structure and side chain interactions stabilize the activation loop of Chk1 and enable kinase activity without phosphorylation of the catalytic domain. Molecular modeling of the interaction of a Cdc25C peptide with Chk1 has uncovered several conserved residues that are important for substrate selectivity. In addition, we found that the less conserved C-terminal region negatively impacts Chk1 kinase activity.

Scalability, reliability, and validity of the benzodiazepine dependence self-report questionnaire in outpatient benzodiazepine users

As there is no multidimensional instrument available that reflects the severity of benzodiazepine (BZD) dependence comprehensively, the Benzodiazepine Dependence Self-Report Questionnaire (Bendep-SRQ) was developed and investigated. The Bendep-SRQ, Symptom Checklist-90 (SCL-90), Schedules for Clinical Assessments in Neuropsychiatry (SCAN), and Addiction Severity Index-Revised (ASI-R) were administered to 115 general practice (GP) patients, 124 psychiatric outpatients, and 33 self-help patients who were using BZDs. Factor and Rasch analyses were applied to construct scales. Reliability assessments were made in terms of subject discriminability, item discriminability, and test-retest stability. To support the construct validity of the scales, theoretical rationales were required to explain the specific item order provided by the Rasch scale values. To assess the concurrent and discriminant validity, a matrix consisting of the above-mentioned measures was factor-analyzed. Four Rasch-homogeneous scales were delineated: problematic use, preoccupation, lack of compliance, and withdrawal. Nearly all subject discriminability, item discriminability, and test-retest results indicated good reliability. A BZD dependence factor was extracted with high loadings for the Bendep-SRQ scales and the concurrent measures. The discriminant measures had high loadings on other factors. The scalability, reliability, and validity of the Bendep-SRQ scales appeared to be good. The Bendep-SRQ shows great promise as a useful and easily manageable instrument for assessment of the severity of BZD dependence in clinical practice and scientific research.

Crystal structure of the kinase domain of human vascular endothelial growth factor receptor 2: a key enzyme in angiogenesis

BACKGROUND

Angiogenesis is involved in tumor growth, macular degeneration, retinopathy and other diseases. Vascular endothelial growth factor (VEGF) stimulates angiogenesis by binding to specific receptors (VEGFRs) on the surface of vascular endothelial cells. VEGFRs are receptor tyrosine kinases that, like the platelet-derived growth factor receptors (PDGFRs), contain a large insert within the kinase domain.

RESULTS

We report here the generation, kinetic characterization, and 2.4 A crystal structure of the catalytic kinase domain of VEGF receptor 2 (VEGFR2). This protein construct, which lacks 50 central residues of the 68-residue kinase insert domain (KID), has comparable kinase activity to constructs containing the entire KID. The crystal structure, determined in an unliganded phosphorylated state, reveals an overall fold and catalytic residue positions similar to those observed in other tyrosine-kinase structures. The kinase activation loop, autophosphorylated on Y1059 prior to crystallization, is mostly disordered; however, a portion of it occupies a position inhibitory to substrate binding. The ends of the KID form a beta-like structure, not observed in other known tyrosine kinase structures, that packs near to the kinase C terminus.

CONCLUSIONS

The majority of the VEGFR2 KID residues are not necessary for kinase activity. The unique structure observed for the ends of the KID may also occur in other PDGFR family members and may serve to properly orient the KID for signal transduction. This VEGFR2 kinase structure provides a target for design of selective anti-angiogenic therapeutic agents.

Role of His-224 in the anomalous pH dependence of human stromelysin-1

A plot of the pH dependence of kcat/KM for human stromelysin-1 (HS) exhibits a narrow range of maximal activity extending from pH 5.75 to 6.25 and a broad shoulder in the pH range of 7.5-8.5. In contrast, the pH profiles that have been reported for other members of the matrix metalloproteinase (MMP) family are bell-shaped and exhibit neutral pH optima. We hypothesized that the anomalous pH dependence of HS reflects the ionization of His-224, a residue located in a flexible loop that contributes to the S1' binding pocket of the enzyme. HS is the only known MMP that has a histidine in this position. To test this hypothesis, the H224Q mutant of the short form (lacking the C-terminal hemopexin-like domain) of HS (sHS) has been prepared and studied. The pH profile of H224Q sHS is bell-shaped and similar to those reported for other MMPs. Although H224Q and wild-type sHS possess similar activities at pH <6, the kcat/KM of H224Q sHS is more than 5-fold greater than that of the wild-type enzyme at pH >7. These data strongly suggest that the deprotonation of His-224 attenuates the activity of HS, thereby accounting for its low pH optimum and the characteristic shoulder in its pH profile. This attenuation of activity appears to be predominantly a KM effect, reflecting a decrease in the affinity of the enzyme for the peptide substrate.

An evaluation of DSM-III-R and ICD-10 benzodiazepine dependence criteria using Rasch modelling

AIMS

To evaluate the homogeneity of the elements of the Substance Dependence Syndrome (SDS) as applied to benzodiazepines (BZDs) by Rasch modelling.

MEASUREMENTS

The Rasch scaling model was applied to data obtained by administering the SCAN (Schedules for Clinical Assessments in Neuropsychiatry) substance dependence sections. Subsequently, Rasch-homogeneous sets of DSM-III-R and ICD-10 BZD dependence criteria were assessed for subject and item discriminability. To support their construct validity a theoretical rationale was formulated based on the Rasch scale values.

PARTICIPANTS

A heterogeneous sample of 599 outpatient BZD users.

FINDINGS

Only particular subsets of the DSM-III-R and ICD-10 BZD dependence criteria met the requirements for Rasch-homogeneity, which appears to be due to medical aspects of BZD use. The subject and item discriminability results were sufficiently good.

CONCLUSIONS

The DSM-III-R and ICD-10 BZD dependence constructs may need to be redefined. The use of a BZD dependence severity model based on a Rasch-homogeneous scale appears to have greater clinical value than a dichotomous diagnostic model based on an arbitrary cut-off point. We recommend Rasch modelling to investigate the homogeneity of the elements of the SDS across other psychoactive substances.

Expression of human pro-matrix metalloproteinase 3 that lacks the N-terminal 34 residues in Escherichia coli: autoactivation and interaction with tissue inhibitor of metalloproteinase 1 (TIMP-1)

Human pro-matrix metalloproteinase 3 (proMMP-3) lacking the N-terminal 34 amino acids and the C-terminal hemopexin-like domain was expressed in E. coli and used to investigate the process of proenzyme activation and its interaction with an endogenous inhibitor TIMP-1 during activation. The truncated precursor was purified from the E. coli extract in the presence of 5mM EGTA. The active 23.5 kDa form was generated simply by exposure to Ca2+ and Zn2+ but not either by Ca2+ alone or by Zn2+ alone. The rate of MMP-3(deltaC) formation was concentration dependent, indicating that autoactivation is a bimolecular reaction. The truncated precursor was able to interact with the N-terminal domain of TIMP-1 without losing the 48 residue-long propeptide. However, upon a longer incubation, the propeptide was slowly processed, indicating that the association of the N-terminally truncated proMMP-3 with TIMP-1 is weaker than that of the fully activated MMP-3 and TIMP-1. These results indicate that the expression of MMP activities is regulated by endogenous inhibitor TIMPs during their activation processes which provide an additional control mechanism of extracellular matrix breakdown.

High prevalence of benzodiazepine dependence in out-patient users, based on the DSM-III-R and ICD-10 criteria

Despite the fact that there have been many reports on benzodiazepine (BZD) dependence, consensus about its definition has not been reached. Reliable prevalence data to estimate the dependence liability of BZDs are therefore lacking. This study is the first to assess the prevalence of BZD dependence in out-patient BZD users (115-general practice (GP) patients, 124 psychiatric out-patients and 33 self-help patients) on the basis of the DSM-III-R and ICD-10 substance dependence criteria. Past year and lifetime diagnoses of BZD dependence were made by means of the Schedules for Clinical Assessments in Neuropsychiatry (SCAN). High prevalence figures were found, ranging from 40% in the GP patients (DSM-III-R past year) to 97% in the self-help patients (ICD-10 lifetime), indicating that BZD users run a high risk of developing BZD dependence. The clinical management of BZD use could benefit from further development of diagnostic instruments such as a self-report questionnaire which reflects the severity of BZD dependence.

Comparison of human cytomegalovirus (HCMV) protease sequences among laboratory strains and seven clinical isolates

The nucleotide sequence of the human cytomegalovirus (HCMV) protease gene from two laboratory strains and seven clinical isolates, both ganciclovir-sensitive and -resistant, was examined to determine the genetic variability of the HCMV protease catalytic domain and to identify changes that may alter the efficacy of designed protease inhibitors. The Towne strain varied from AD169 at 12 nucleotides and led to one amino acid change at position 12 (Ala to Thr). The clinical isolates had amino acid substitutions relative to the laboratory strains, with a Ser to Pro change at position 8, a His to Tyr change at position 44 and s Gly to Ser change at position 47. None of these changes occurred in any of the conserved domains of the protease, nor do they appear necessary to confer ganciclovir resistance in the isolates. These findings suggest that no changes exist in the protease of the clinical isolates examined that may diminish the effectiveness of a drug targeting the HCMV protease. 1977 Elsevier Science B.V. All rights reserved.