Model-Based Approach for Optimizing Study Design and Clinical Drug Performances of Extended-Release Formulations of Methylphenidate for the Treatment of ADHD

Methylphenidate (MPH) is currently used to treat children with attention deficit hyperactivity disorder (ADHD). Several extended-release (ER) formulations characterized by a dual release process were developed to improve efficacy over an extended duration. In this study, a model-based approach using literature data was developed to: 1) evaluate the most efficient pharmacokinetic (PK) model to characterize the complex PK profile of MPH ER formulations; 2) provide PK endpoint metrics for comparing ER formulations; 3) define criteria for optimizing development of ER formulations using a convolution-based model linking in vitro release, in vivo release, and hour-by-hour behavioral ratings of ADHD symptoms; and 4) define an optimized trial design for assessing the activity of MPH in pediatric populations. The convolution-based model accurately described the complex PK profiles of a variety of ER MPH products, providing a natural framework for establishing an in vitro/in vivo correlation and for defining criteria for assessing comparative bioequivalence of MPH ER products.

The World Health Organization Adult Attention-Deficit/Hyperactivity Disorder Self-Report Screening Scale for DSM-5

Importance

Recognition that adult attention-deficit/hyperactivity disorder (ADHD) is common, seriously impairing, and usually undiagnosed has led to the development of adult ADHD screening scales for use in community, workplace, and primary care settings. However, these scales are all calibrated to DSM-IV criteria, which are narrower than the recently developed DSM-5 criteria.

Objectives

To update for DSM-5 criteria and improve the operating characteristics of the widely used World Health Organization Adult ADHD Self-Report Scale (ASRS) for screening.

Design, Setting, and Participants

Probability subsamples of participants in 2 general population surveys (2001-2003 household survey [n = 119] and 2004-2005 managed care subscriber survey [n = 218]) who completed the full 29-question self-report ASRS, with both subsamples over-sampling ASRS-screened positives, were blindly administered a semistructured research diagnostic interview for DSM-5 adult ADHD. In 2016, the Risk-Calibrated Supersparse Linear Integer Model, a novel machine-learning algorithm designed to create screening scales with optimal integer weights and limited numbers of screening questions, was applied to the pooled data to create a DSM-5 version of the ASRS screening scale. The accuracy of the new scale was then confirmed in an independent 2011-2012 clinical sample of patients seeking evaluation at the New York University Langone Medical Center Adult ADHD Program (NYU Langone) and 2015-2016 primary care controls (n = 300). Data analysis was conducted from April 4, 2016, to September 22, 2016.

Main Outcomes and Measures

The sensitivity, specificity, area under the curve (AUC), and positive predictive value (PPV) of the revised ASRS.

Results

Of the total 637 participants, 44 (37.0%) household survey respondents, 51 (23.4%) managed care respondents, and 173 (57.7%) NYU Langone respondents met DSM-5 criteria for adult ADHD in the semistructured diagnostic interview. Of the respondents who met DSM-5 criteria for adult ADHD, 123 were male (45.9%); mean (SD) age was 33.1 (11.4) years. A 6-question screening scale was found to be optimal in distinguishing cases from noncases in the first 2 samples. Operating characteristics were excellent at the diagnostic threshold in the weighted (to the 8.2% DSM-5/Adult ADHD Clinical Diagnostic Scale population prevalence) data (sensitivity, 91.4%; specificity, 96.0%; AUC, 0.94; PPV, 67.3%). Operating characteristics were similar despite a much higher prevalence (57.7%) when the scale was applied to the NYU Langone clinical sample (sensitivity, 91.9%; specificity, 74.0%; AUC, 0.83; PPV, 82.8%).

Conclusions and Relevance

The new ADHD screening scale is short, easily scored, detects the vast majority of general population cases at a threshold that also has high specificity and PPV, and could be used as a screening tool in specialty treatment settings.

Abnormal fear circuitry in Attention Deficit Hyperactivity Disorder: A controlled magnetic resonance imaging study

We examined whether non-traumatized subjects with Attention Deficit Hyperactivity Disorder (ADHD) have dysfunctional activation in brain structures mediating fear extinction, possibly explaining the statistical association between ADHD and other disorders characterized by aberrant fear processing such as PTSD. Medication naïve, non-traumatized young adult subjects with (N=27) and without (N=20) ADHD underwent a 2-day fear conditioning and extinction protocol in a 3T functional magnetic resonance imaging (fMRI) scanner. Skin conductance response (SCR) was recorded as a measure of conditioned response. Compared to healthy controls, ADHD subjects had significantly greater insular cortex activation during early extinction, lesser dorsal anterior cingulate cortex (dACC) activation during late extinction, lesser ventromedial prefrontal cortex (vmPFC) activation during late extinction learning and extinction recall, and greater hippocampal activation during extinction recall. Hippocampal and vmPFC deficits were similar to those documented in PTSD subjects compared to traumatized controls without PTSD. Non-traumatized, medication naive adults with ADHD had abnormalities in fear circuits during extinction learning and extinction recall, and some findings were consistent with those previously documented in subjects with PTSD compared to traumatized controls without PTSD. These findings could explain the significant association between ADHD and PTSD as well as impaired emotion regulation in ADHD.

The structure of adult ADHD

Although DSM-5 stipulates that symptoms of attention-deficit hyperactivity disorder (ADHD) are the same for adults as children, clinical observations suggest that adults have more diverse deficits than children in higher-level executive functioning and emotional control. Previous psychometric analyses to evaluate these observations have been limited in ways addressed in the current study, which analyzes the structure of an expanded set of adult ADHD symptoms in three pooled US samples: a national household sample, a sample of health plan members, and a sample of adults referred for evaluation at an adult ADHD clinic. Exploratory factor analysis found four factors representing executive dysfunction/inattention (including, but not limited to, all the DSM-5 inattentive symptoms, with non-DSM symptoms having factor loadings comparable to those of DSM symptoms), hyperactivity, impulsivity, and emotional dyscontrol. Empirically-derived multivariate symptom profiles were broadly consistent with the DSM-5 inattentive-only, hyperactive/impulsive-only, and combined presentations, but with inattention including executive dysfunction/inattention and hyperactivity-only limited to hyperactivity without high symptoms of impulsivity. These results show that executive dysfunction is as central as DSM-5 symptoms to adult ADHD, while emotional dyscontrol is more distinct but nonetheless part of the combined presentation of adult ADHD.

The Neuropsychological Profile of Comorbid Post-Traumatic Stress Disorder in Adult ADHD

OBJECTIVE

ADHD and post-traumatic stress disorder (PTSD) are often comorbid yet despite the increased comorbidity between the two disorders, to our knowledge, no data have been published regarding the neuropsychological profile of adults with comorbid ADHD and PTSD. Likewise, previous empirical studies of the neuropsychology of PTSD did not control for ADHD status. We sought to fill this gap in the literature and to assess the extent to which neuropsychological test performance predicted psychosocial functioning, and perceived quality of life.

METHOD

Participants were 201 adults with ADHD attending an outpatient mental health clinic between 1998 and 2003 and 123 controls without ADHD. Participants completed a large battery of self-report measures and psychological tests. Diagnoses were made using data obtained from structured psychiatric interviews (i.e., Structured Clinical Interview for DSM-IV, Schedule for Affective Disorders and Schizophrenia for School-Age Children Epidemiologic Version).

RESULTS

Differences emerged between control participants and participants with ADHD on multiple neuropsychological tests. Across all tests, control participants outperformed participants with ADHD. Differences between the two ADHD groups emerged on seven psychological subtests including multiple Wechsler Adult Intelligence Scale-Third edition and Rey-Osterrieth Complex Figure Test measures. These test differences did not account for self-reported quality of life differences between groups.

CONCLUSION

The comorbidity with PTSD in adults with ADHD is associated with weaker cognitive performance on several tasks that appear related to spatial/perceptual abilities and fluency. Neuropsychological test performances may share variance with the quality of life variables yet are not mediators of the quality of life ratings.

Local membrane length conservation in two-dimensional vesicle simulation using a multicomponent lattice Boltzmann equation method

We present a method for applying a class of velocity-dependent forces within a multicomponent lattice Boltzmann equation simulation that is designed to recover continuum regime incompressible hydrodynamics. This method is applied to the problem, in two dimensions, of constraining to uniformity the tangential velocity of a vesicle membrane implemented within a recent multicomponent lattice Boltzmann simulation method, which avoids the use of Lagrangian boundary tracers. The constraint of uniform tangential velocity is carried by an additional contribution to an immersed boundary force, which we derive here from physical arguments. The result of this enhanced immersed boundary force is to apply a physically appropriate boundary condition at the interface between separated lattice fluids, defined as that region over which the phase-field varies most rapidly. Data from this enhanced vesicle boundary method are in agreement with other data obtained using related methods [e.g., T. Krüger, S. Frijters, F. Günther, B. Kaoui, and J. Harting, Eur. Phys. J. 222, 177 (2013)10.1140/epjst/e2013-01834-y] and underscore the importance of a correct vesicle membrane condition.

Examining the association between posttraumatic stress disorder and attention-deficit/hyperactivity disorder: a systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis examining the relationship between attention-deficit/hyperactivity disorder (ADHD) and posttraumatic stress disorder (PTSD).

DATA SOURCES

We reviewed literature through PubMed and PsycINFO without a specified date range, utilizing the search (posttraumatic stress disorder OR PTSD) AND (ADHD OR attention deficit hyperactivity disorder OR ADD OR attention deficit disorder OR hyperkinetic syndrome OR minimal brain dysfunction). References from relevant articles were reviewed.

STUDY SELECTION

We identified 402 articles; 28 met criteria. We included original human research in English that operationalized diagnoses of ADHD and PTSD, evaluated the relationship between the disorders, and included controls. We excluded articles that failed to differentiate ADHD or PTSD from nonspecific or subsyndromal deficits or failed to compare their relationship.

DATA EXTRACTION

We extracted sample size, age, diagnostic methods, design, referral status, control type, and number of subjects with and without ADHD and PTSD alone and combined. We computed meta-analyses for 22 studies examining ADHD in PTSD and PTSD in ADHD using a random effects model and meta-analytic regression. We assessed for heterogeneity and publication bias and adjusted for intrastudy clustering.

RESULTS

The relative risk (RR) for PTSD in ADHD was 2.9 (P < .0005); in samples using healthy controls, the RR was 3.7 (P = .001); and in samples using traumatized controls, the RR was 1.6 (P = .003). The RR for ADHD in PTSD was 1.7 (P < .0005); in samples using traumatized controls, the RR was 2.1 (P < .0005). The association was not significant in samples using psychiatric controls.

CONCLUSIONS

Results indicate a bidirectional association between ADHD and PTSD, suggesting clinical implications and highlighting the need for neurobiological research that examines the mechanisms underlying this connection.

Toward Defining the Neural Substrates of ADHD: A Controlled Structural MRI Study in Medication-Naïve Adults

OBJECTIVE

We assessed the neural correlates of adult ADHD in treatment-naïve participants, an approach necessary for identifying neural substrates unconfounded by medication effects.

METHOD

The sample consisted of 24 medication-naïve adults with Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) diagnosed ADHD and 24 healthy controls, comparable on age, sex, handedness, reading achievement, IQ, and psychiatric comorbidity. All participants were assessed with structured diagnostic interviews. Magnetic resonance imaging (MRI)-based regional voxel-based morphometry (r-VBM) was used to assess volumetric differences in a priori defined brain regions of interest.

RESULTS

VBM analysis revealed group differences in the hypothesized cortical and subcortical areas; however, only cerebellar volume reductions in ADHD retained significance (p < .05) after corrections for multiple comparisons.

CONCLUSION

These results support the notion that medication-naïve ADHD as expressed in adulthood, manifests subtle brain volume reductions from normal in the cerebellum, and possibly in other syndrome-congruent gray-matter structures. Larger samples are required to confirm these findings.

Mild traumatic brain injury and ADHD: a systematic review of the literature and meta-analysis

OBJECTIVE

This study investigated the association between mild traumatic brain injury (mTBI) and ADHD, which increases risk of injuries and accidents.

METHOD

We conducted a systematic review and meta-analysis of studies that examined the relationship between mTBI and ADHD.

RESULTS

Five studies, comprising 3,023 mTBI patients and 9,716 controls, fit our a priori inclusion and exclusion criteria. A meta-analysis found a significant association between ADHD and mTBI, which was significant when limited to studies that reported on ADHD subsequent to mTBI and when the direction of the association was not specified, but not for studies that reported mTBI subsequent to ADHD. Heterogeneity of effect size and publication biases were not evident.

CONCLUSION

The literature documents a significant association between mTBI and ADHD. Further clarification of the relationship and direction of effect between mTBI and ADHD and treatment implications could have large clinical, scientific, and public health implications.

Is ADHD a risk for posttraumatic stress disorder (PTSD)? Results from a large longitudinal study of referred children with and without ADHD

OBJECTIVES

Preclinical studies link prenatal nicotine exposure with the development of both ADHD-like phenotype in rodents and blockade of extinction learning in a fear conditioning paradigm, a preclinical model of posttraumatic stress disorder (PTSD). While these findings suggest that either ADHD, prenatal nicotine exposure, or both could be a risk factor for PTSD, such associations have not been investigated in humans.

METHODS

Subjects were ascertained from family-genetic, longitudinal studies of paediatrically and psychiatrically referred children with and without ADHD of both sexes and their siblings followed for 10 years from childhood into adulthood (n = 403 probands; n = 464 siblings; mean age at follow-up of probands and siblings = 22.0 years). All subjects were comprehensively evaluated with structured diagnostic interviews that included questions regarding prenatal use of cigarettes.

RESULTS

A total of 12% (104/867) of the sample had been exposed to maternal smoking during pregnancy. There was no interaction effect between maternal smoking during pregnancy and ADHD (z = 0.01, P = 0.99). Maternal smoking during pregnancy and ADHD were independent, significant risk factors for PTSD at the 10-year follow-up (odds ratio = 3.58 [1.35,9.48], z = 2.57, P = 0.01 and odds ratio = 2.23 [1.06,4.69], z = 2.11, P = 0.04, respectively).

CONCLUSIONS

These results suggest that both maternal smoking during pregnancy and ADHD are significant predictors of PTSD in humans.

Multicomponent lattice Boltzmann equation method with a discontinuous hydrodynamic interface

In the multicomponent lattice Boltzmann equation simulation method (MCLB), applied to the continuum regime of fluid flow, the finite width of the fluid-fluid interface introduces unphysical scales. We present a practical, robust, computationally efficient, and easy to implement solution to this problem which needs only low order interpolation to be stable and accurate and is applicable to any MCLB variant which uses a continuous phase field to distinguish between immiscible fluids with arrested coalescence. Our method extends the ideas of Kim and Pitsch, [Phys. Fluids 19, 108101 (2007)] and uses no external force distribution whatsoever to generate continuum interfacial physics, i.e., the Laplace law and no traction conditions on interfacial stresses. As such, it is amenable to the simplest form of Chapman-Enskog analysis used for lattice Boltzmann models. We assess our method and proceed to compare key results obtained with it against other equivalent data, obtained using the established continuum regime MCLB technique based upon the work of Lishchuk, Care, and Halliday, [Phys. Rev. E 67, 036701 (2003)] and Halliday, Hollis, and Care, [Phys. Rev. E 76, 026708 (2007)], quantifying performance in terms of the minimum feasible capillary available to simulation using that technique.

Effect of psychostimulants on brain structure and function in ADHD: a qualitative literature review of magnetic resonance imaging-based neuroimaging studies

OBJECTIVE

To evaluate the impact of therapeutic oral doses of stimulants on the brains of ADHD subjects as measured by magnetic resonance imaging (MRI)-based neuroimaging studies (morphometric, functional, spectroscopy).

DATA SOURCES

We searched PubMed and ScienceDirect through the end of calendar year 2011 using the keywords (1) psychostimulants or methylphenidate or amphetamine, and (2) neuroimaging or MRI or fMRI, and (3) ADHD or ADD or attention-deficit/hyperactivity disorder or attention deficit hyperactivity disorder.

STUDY SELECTION

We included only English language articles with new data from case-control or placebo controlled studies that examined attention-deficit/hyperactivity disorder (ADHD) subjects on and off psychostimulants (as well as 5 relevant review articles).

DATA EXTRACTION

We combined details of study design and medication effects in each imaging modality.

RESULTS

We found 29 published studies that met our criteria. These included 6 structural MRI, 20 functional MRI studies, and 3 spectroscopy studies. Methods varied widely in terms of design, analytic technique, and regions of the brain investigated. Despite heterogeneity in methods, however, results were consistent. With only a few exceptions, the data on the effect of therapeutic oral doses of stimulant medication suggest attenuation of structural and functional alterations found in unmedicated ADHD subjects relative to findings in controls.

CONCLUSIONS

Despite the inherent limitations and heterogeneity of the extant MRI literature, our review suggests that therapeutic oral doses of stimulants decrease alterations in brain structure and function in subjects with ADHD relative to unmedicated subjects and controls. These medication-associated brain effects parallel, and may underlie, the well-established clinical benefits.

Functional genomics of attention-deficit/hyperactivity disorder (ADHD) risk alleles on dopamine transporter binding in ADHD and healthy control subjects

BACKGROUND

The main aim of this study was to examine the relationship between dopamine transporter (DAT) binding in the striatum in individuals with and without attention-deficit/hyperactivity disorder (ADHD), attending to the 3'-untranslated region of the gene (3'-UTR) and intron8 variable number of tandem repeats (VNTR) polymorphisms of the DAT (SLC6A3) gene.

METHODS

Subjects consisted of 68 psychotropic (including stimulant)-naïve and smoking-naïve volunteers between 18 and 55 years of age (ADHD n = 34; control subjects n = 34). Striatal DAT binding was measured with positron emission tomography with 11C altropane. Genotyping of the two DAT (SLC6A3) 3'-UTR and intron8 VNTRs used standard protocols.

RESULTS

The gene frequencies of each of the gene polymorphisms assessed did not differ between the ADHD and control groups. The ADHD status (t = 2.99; p<.004) and 3'-UTR of SLC6A3 9 repeat carrier status (t = 2.74; p<.008) were independently and additively associated with increased DAT binding in the caudate. The ADHD status was associated with increased striatal (caudate) DAT binding regardless of 3'-UTR genotype, and 3'-UTR genotype was associated with increased striatal (caudate) DAT binding regardless of ADHD status. In contrast, there were no significant associations between polymorphisms of DAT intron8 or the 3'-UTR-intron8 haplotype with DAT binding.

CONCLUSIONS

The 3'-UTR but not intron8 VNTR genotypes were associated with increased DAT binding in both ADHD patients and healthy control subjects. Both ADHD status and the 3'-UTR polymorphism status had an additive effect on DAT binding. Our findings suggest that an ADHD risk polymorphism (3'-UTR) of SLC6A3 has functional consequences on central nervous system DAT binding in humans.

Examining the nature of the comorbidity between pediatric attention deficit/hyperactivity disorder and post-traumatic stress disorder

OBJECTIVE

This study sought to address the link between attention deficit/hyperactivity disorder (ADHD) and post-traumatic stress disorder (PTSD) in youth by providing a comprehensive comparison of clinical correlates of ADHD subjects with and without PTSD across multiple non-overlapping domains of functioning and familial patterns of transmission.

METHOD

Participants were 271 youths with ADHD and 230 controls without ADHD of both sexes along with their siblings. Participants completed a large battery of measures designed to assess psychiatric comorbidity, psychosocial, educational, and cognitive parameters.

RESULTS

Post-traumatic stress disorder was significantly higher in ADHD probands vs. controls (5.2% vs. 1.7%, χ(2) (1) = 4.36, P = 0.04). Irrespective of the comorbidity with PTSD, ADHD subjects had similar ages at onset of ADHD, similar type and mean number of ADHD symptoms, and similar ADHD-associated impairments. PTSD in ADHD probands was significantly associated with a higher risk of psychiatric hospitalization, school impairment, poorer social functioning and higher prevalences of mood, conduct disorder, and anxiety disorders. The mean onset of PTSD (12.6 years) was significantly later than that of ADHD and comorbid disorders (all P < 0.05). Siblings of ADHD and ADHD + PTSD probands had higher prevalences of ADHD vs. siblings of controls (35% vs. 18%, z = 4.00, P < 0.001 and 67% vs. 18%, z = 4.02, P < 0.001 respectively) and siblings of ADHD+PTSD probands had a significantly higher prevalence of PTSD compared with the siblings of ADHD and control probands (20% vs. 3% and 3%, z = 2.99, P = 0.003 and z = 2.07, P = 0.04 respectively).

CONCLUSION

Findings indicate that the comorbidity with PTSD in ADHD leads to greater clinical severity as regards psychiatric comorbidity and psychosocial dysfunction. ADHD is equally familial in the presence of PTSD in the proband indicating that their co-occurrence is not owing to diagnostic error.

Personal and familial correlates of bipolar (BP)-I disorder in children with a diagnosis of BP-I disorder with a positive child behavior checklist (CBCL)-severe dysregulation profile: a controlled study

BACKGROUND

Although the DSM-IV provides explicit criteria for the diagnosis of BP-I disorder, this is a complex diagnosis that requires high levels of clinical expertise. Previous work shows children with a unique profile of the CBCL of high scores (2SD) on the attention problems (AP), aggressive behavior (AGG), and anxious-depressed (AD) (A-A-A) subscales are more likely than other children to meet criteria for BP-I disorder in both epidemiological and clinical samples. However, since not all BP-I disorder children have a positive profile questions remain as to its informativeness, particularly in the absence of an expert diagnostician.

METHODS

Analyses were conducted comparing personal and familial correlates of BP-I disorder in 140 youth with a structured interview and an expert clinician based DSM-IV diagnosis of BP-I disorder with (N=80) and without (N=60) a positive CBCL- Severe Dysregulation profile, and 129 controls of similar age and sex without ADHD or a mood disorder. Subjects were comprehensively assessed with structured diagnostic interviews and wide range of functional measures. We defined the CBCL-severe dysregulation profile as an aggregate cut-off score of ≥ 210 on the A-A-A scales.

RESULTS

BP-I probands with and without a positive CBCL-severe dysregulation profile significantly differed from Controls in patterns of psychiatric comorbidity, psychosocial and psychoeducational dysfunction, and cognitive deficits, as well as in their risk for BP-I disorder in first degree relatives.

LIMITATIONS

Because the sample was referred and largely Caucasian, findings may not generalize to community samples and other ethnic groups.

CONCLUSION

A positive CBCL-severe dysregulation profile identifies a severe subgroup of BP-I disorder youth.

Posttraumatic stress disorder in adult attention-deficit/hyperactivity disorder: clinical features and familial transmission

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is characterized by clinically significant functional impairment due to symptoms of inattention and/or hyperactivity and impulsivity. Previous research suggests a link, in child samples, between ADHD and posttraumatic stress disorder (PTSD), which is characterized by (1) chronically reexperiencing a traumatic event, (2) hyperarousal, and (3) avoiding stimuli associated with the trauma while exhibiting numbed responsiveness. This study sought to address the link between ADHD and PTSD in adults by providing a comprehensive comparison of ADHD patients with and without PTSD across multiple variables including demographics, patterns of psychiatric comorbidities, functional impairments, quality of life, social adjustment, and familial transmission.

METHOD

Participants in our controlled family study conducted between 1998 and 2003 were 190 adults with DSM-IV ADHD who were attending an outpatient mental health clinic in Boston, Massachusetts; 16 adults with DSM-IV ADHD who were recruited by advertisement from the greater Boston area; and 123 adult controls without ADHD who were recruited by advertisement from the greater Boston area. All available first-degree relatives also participated. Subjects completed a large battery of self-report measures (the Quality of Life Enjoyment and Satisfaction Questionnaire, items from the Current Behavior Scale, the Social Adjustment Scale Self-Report, and the Four Factor Index of Social Status) designed to assess various psychiatric and functional parameters. Diagnoses were made using data obtained from structured psychiatric interviews (Structured Clinical Interview for DSM-IV Axis I Disorders, Clinician Version, and the Schedule for Affective Disorders and Schizophrenia for School-Aged Children-Epidemiologic Version).

RESULTS

The lifetime prevalence of PTSD was significantly higher among adults with ADHD compared with controls (10.0% vs 1.6%; P = .004). Participants with ADHD and those with ADHD + PTSD did not differ in core symptoms of ADHD nor in age at onset, but those with ADHD + PTSD had higher rates of psychiatric comorbidity than those with ADHD only (including higher lifetime rates of major depressive disorder, oppositional defiant disorder, social phobia, agoraphobia, and generalized anxiety disorder) and worse quality of life ratings for all domains. Familial risk analysis revealed that relatives of ADHD probands without PTSD had elevated rates of both ADHD (51%) and PTSD (12%) that significantly differed from rates among relatives of controls (7% [P ≤ .001] and 0% [P ≤ .05], respectively). A similar pattern of elevated risk for ADHD and PTSD (80% and 40%) was observed in relatives of probands with ADHD + PTSD (P ≤ .001 for both conditions).

CONCLUSIONS

The comorbidity of PTSD and ADHD in adults leads to greater clinical severity in terms of psychiatric comorbidity and psychosocial functioning. The familial coaggregation of the 2 disorders suggests that these disorders share familial risk factors and that their co-occurrence is not due to diagnostic errors.

Multiple-component lattice Boltzmann equation for fluid-filled vesicles in flow

We document the derivation and implementation of extensions to a two-dimensional, multicomponent lattice Boltzmann equation model, with Laplace law interfacial tension. The extended model behaves in such a way that the boundary between its immiscible drop and embedding fluid components can be shown to describe a vesicle of constant volume bounded by a membrane with conserved length, specified interface compressibility, bending rigidity, preferred curvature, and interfacial tension. We describe how to apply this result to several, independent vesicles. The extended scheme is completely Eulerian, and it represents a two-way coupled vesicle membrane and flow within a single framework. Unlike previous methods, our approach dispenses entirely with the need explicitly to track the membrane, or boundary, and makes no use whatsoever of computationally expensive and intricate interface tracking and remeshing. Validation data are presented, which demonstrate the utility of the method in the simulation of the flow of high volume fraction suspensions of deformable objects.

Preliminary examination of the reliability and concurrent validity of the attention-deficit/hyperactivity disorder self-report scale v1.1 symptom checklist to rate symptoms of attention-deficit/hyperactivity disorder in adolescents

OBJECTIVE

To validate the attention-deficit/hyperactivity disorder (ADHD) Self-Report Scale (ASRS) v1.1 Symptom Checklist versus the clinician-administered ADHD Rating Scale (ADHD-RS) in adolescents with ADHD.

METHOD

A total of 88 adolescents with ADHD aged 13-17 years participated in the study. The study was completed in one or two visits, 1-9 weeks apart. At each visit, participants completed the ASRS v1.1 Symptom Checklist, after which raters administered the ADHD-RS. Internal consistency of the ASRS v1.1 Symptom Checklist was assessed by Cronbach's alpha (Cronbach's α). Concurrent validity between the scales was assessed using Pearson's correlation coefficients. Item-by-item reliability between the scales was assessed by the Kappa coefficient of agreement.

RESULTS

The mean age of participants was 14.9±1.5 SD years. 76.1% (n=67) were male. 73.9% (n=65) were currently receiving medication for ADHD. Internal consistency of ASRS v1.1 Symptom Checklist items was high, with Cronbach's α coefficients of 0.93 at Visit 1 and 0.94 at Visit 2. Pearson's correlation coefficients between the ASRS v1.1 Symptom Checklist and ADHD-RS were highly significant at Visit 1 (r=0.72, p<0.0001) and Visit 2 (r=0.73, p<0.0001). There was moderate item-by-item agreement between individual items on the scales (% agreement: 35.2%-63.4%) with statistically significant kappa coefficients for 17 of the 18 items.

CONCLUSION

The ASRS v1.1 Symptoms Checklist showed high internal consistency and high concurrent validity with the clinician-administered ADHD-RS in adolescents with ADHD. Results of this study suggest that the ASRS v1.1 Symptom Checklist is an internally consistent self-report scale for the assessment of adolescent ADHD and is moderately associated with a concurrently administered clinician measure of ADHD symptoms.

Importance of pharmacokinetic profile and timing of coadministration of short- and long-acting formulations of methylphenidate on patterns of subjective responses and abuse potential

OBJECTIVE

Subjective responses (ie, liking, disliking) to stimulants are thought to be proxies for abuse potential. Greater subjective responses have been documented in formulations that are more rapidly absorbed. However, repeat dosing has not been examined.

METHODS

Subjective responses on the Drug Rating Questionnaire were compared in 26 healthy adults after administration of short- (immediate-release [IR] methylphenidate [MPH]) and long- (osmotically controlled-release oral delivery system [OROS] MPH) acting stimulant formulations. The second dose was administered 4 hours after initial dosing. All subjects received all 5 conditions (ie, placebo to placebo; IR-MPH to IR-MPH; IR-MPH to OROS-MPH; OROS-MPH to IR-MPH; or OROS-MPH to OROS-MPH) in a double-blind, counter-balanced design on 5 separate days.

RESULTS

Plasma levels and subjective patterns of detection were higher when an IR formulation was administered during the ascending phase of a first-administered long-acting dose (OROS).

CONCLUSION

These results emphasize the critical role that formulation type (IR vs OROS) and timing of administration (ascending vs descending phase) play when short- and long-acting formulations are coadministered. Such knowledge provides important information for clinicians about the safety and tolerability of the timing of repeat dosing of various permutations of coadministration of MPH formulations.

Understanding the central pharmacokinetics of spheroidal oral drug absorption system (SODAS) dexmethylphenidate: a positron emission tomography study of dopamine transporter receptor occupancy measured with C-11 altropane

OBJECTIVE

Pediatric studies of the long-acting formulation (spheroidal oral drug absorption system [SODAS]) of the isomer dexmethylphenidate have shown a dose-dependent efficacy through 12 hours. However, there are no studies of central nervous system (CNS) dopamine transporter occupancies.

METHOD

Eighteen healthy volunteers underwent positron emission tomography (PET) imaging with C-11 altropane before and after administration of oral doses of SODAS dexmethylphenidate. Each group of 6 subjects received 1 of 3 doses (20 mg, 30 mg, 40 mg) before PET imaging at 1, 8, 10, 12 (20 mg and 30 mg), or 1, 8, 10, and 14 (40 mg) hours after dosing. Transporter occupancy was calculated by standard methods. The study was conducted from January 2007 through December 2007.

RESULTS

For all doses, plasma dexmethylphenidate levels and CNS dopamine transporter occupancies were greatest at 8 hours and decreased over time at 10, 12, and 14 hours. Plasma dexmethylphenidate levels were correlated to dose (P < .003). Mean plasma levels were ≥ 6 ng/mL to at least 8 hours with 20 mg (5.7 ng/mL), 10 hours with 30 mg, and 12 hours (extrapolated) with 40 mg. Dopamine transporter occupancies in the right caudate were 47% at 8 hours with 20 mg, 42% at hour 10 with 30 mg, and 46% (extrapolated) at hour 12 with 40 mg. Dopamine transporter occupancy was significantly correlated with plasma concentration of dexmethylphenidate (P < .001).

CONCLUSIONS

These results confirm the study hypothesis that central dopamine transporter occupancy parallels peripheral pharmacokinetic findings in orally administered long-acting dexmethylphenidate in later hours after administration.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00593138.

Dose response effects of lisdexamfetamine dimesylate treatment in adults with ADHD: an exploratory study

OBJECTIVE

To explore dose-response effects of lisdexamfetamine dimesylate (LDX) treatment for ADHD.

METHOD

This was a 4-week, randomized, double-blinded, placebo-controlled, parallel-group, forced-dose titration study in adult participants, aged 18 to 55 years, meeting Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.) criteria for ADHD.

RESULTS

Nearly all participants assigned to an LDX dose achieved their assigned dose with the exception of about 4% of participants assigned to the 50 mg or 14% assigned to the 70 mg doses. Higher doses of LDX led to greater improvements in ADHD-rating scale scores, independent of prior pharmacotherapy. This was evident for both inattentive and hyperactive-impulsive symptoms. The authors found some evidence for an interaction between LDX dose and baseline severity of ADHD symptoms.

CONCLUSION

For LDX doses between 30 and 70 mg/d, the dose-response efficacy effect for LDX is not affected by prior pharmacotherapy, but patients with a greater severity of illness may benefit more from higher doses, especially for hyperactive-impulsive symptoms. The results do not provide information about doses above 70 mg/d, which is the maximum approved dose of LDX and the highest dose studied in ADHD clinical trials.

Longitudinal course of deficient emotional self-regulation CBCL profile in youth with ADHD: prospective controlled study

BACKGROUND

While symptoms of deficient emotional self-regulation (DESR) have been long associated with attention-deficit/hyperactivity disorder (ADHD), there has been limited investigation of this aspect of the clinical picture of the disorder. The main aim of this study was to examine the predictive utility of DESR in moderating the course of ADHD children into adolescence.

METHODS

Subjects comprised 177 children with and 204 children without ADHD followed for an average of 4 years (aged 6-18 years at baseline, 54% male). Subjects were assessed with structured diagnostic interviews and measures of psychosocial functioning. DESR was defined by the presence (n = 79) or absence (n = 98) of Child Behavior Checklist (CBCL)-DESR profile (score ≥ 180 < 210 total of Attention, Aggression, and Anxious/Depressed subscales) at the baseline assessment.

RESULTS

Of subjects with DESR at baseline, 57% had DESR at follow-up. Persistent ADHD was significantly associated with DESR at follow-up (χ(2) ((1)) = 15.37, P < 0.001). At follow-up, ADHD + DESR subjects had significantly more comorbidities (z = 2.55, P = 0.01), a higher prevalence of oppositional defiant disorder (z = 3.01, P = 0.003), and more impaired CBCL social problems t-score (t((227)) = 2.41, P = 0.02) versus ADHD subjects.

CONCLUSION

This work suggests that a positive CBCL-DESR profile predicts subsequent psychopathology and functional impairments in children with ADHD suggesting that it has the potential to help identify children with ADHD at high risk for compromised outcomes.