J. Antoni Ramos-Quiroga

An independent components and functional connectivity analysis of resting state fMRI data points to neural network dysregulation in adult ADHD

Spontaneous fluctuations can be measured in the brain that reflect dissociable functional networks oscillating at synchronized frequencies, such as the default mode network (DMN). In contrast to its diametrically opposed task‐positive counterpart, the DMN predominantly signals during a state of rest, and inappropriate regulation of this network has been associated with inattention, a core characteristic of attention‐deficit/hyperactivity disorder (ADHD). To examine whether abnormalities can be identified in the DMN component of patients with ADHD, we applied an independent components analysis to resting state functional magnetic resonance imaging data acquired from 22 male medication‐naïve adults with ADHD and 23 neurotypical individuals. We observed a stronger coherence of the left dorsolateral prefrontal cortex (dlPFC) with the DMN component in patients with ADHD which correlated with measures of selective attention. The increased left dlPFC‐DMN coherence also surfaced in a whole‐brain replication analysis involving an independent sample of 9 medication‐naïve adult patients and 9 controls. In addition, a post hoc seed‐to‐voxel functional connectivity analysis using the dlPFC as a seed region to further examine this regions suggested connectivity differences uncovered a higher temporal coherence with various other neural networks and confirmed a reduced anticorrelation with the DMN. These results point to a more diffuse connectivity between functional networks in patients with ADHD. Moreover, our findings suggest that state‐inappropriate neural activity in ADHD is not confined to DMN intrusion during attention‐demanding contexts, but also surfaces as an insufficient suppression of dlPFC signaling in relation to DMN activity during rest. Together with previous findings, these results point to a general dysfunction in the orthogonality of functional networks. Hum Brain Mapp 35:1261–1272, 2014.

Variability in the prevalence of adult ADHD in treatment seeking substance use disorder patients: Results from an international multi-center study exploring DSM-IV and DSM-5 criteria

Background Available studies vary in their estimated prevalence of attention deficit/hyperactivity disorder (ADHD) in substance use disorder (SUD) patients, ranging from 2 to 83%. A better understanding of the possible reasons for this variability and the effect of the change from DSM-IV to DSM-5 is needed. Methods A two stage international multi-center, cross-sectional study in 10 countries, among patients form inpatient and outpatient addiction treatment centers for alcohol and/or drug use disorder patients. A total of 3558 treatment seeking SUD patients were screened for adult ADHD. A subsample of 1276 subjects, both screen positive and screen negative patients, participated in a structured diagnostic interview. Results Prevalence of DSM-IV and DSM-5 adult ADHD varied for DSM-IV from 5.4% (CI 95%: 2.4–8.3) for Hungary to 31.3% (CI 95%:25.2–37.5) for Norway and for DSM-5 from 7.6% (CI 95%: 4.1–11.1) for Hungary to 32.6% (CI 95%: 26.4–38.8) for Norway. Using the same assessment procedures in all countries and centers resulted in substantial reduction of the variability in the prevalence of adult ADHD reported in previous studies among SUD patients (2–83%→ 5.4–31.3%). The remaining variability was partly explained by primary substance of abuse and by country (Nordic versus non-Nordic countries). Prevalence estimates for DSM-5 were slightly higher than for DSM-IV. Conclusions Given the generally high prevalence of adult ADHD, all treatment seeking SUD patients should be screened and, after a confirmed diagnosis, treated for ADHD since the literature indicates poor prognoses of SUD in treatment seeking SUD patients with ADHD.

Response inhibition and reward anticipation in medication-naïve adults with attention-deficit/hyperactivity disorder: a within-subject case-control neuroimaging study.

Background: Previous research suggests that ADHD patients are characterized by both reduced activity in the inferior frontal gyrus (IFG) during response inhibition tasks (such as the Go‐NoGo task), and reduced activity in the ventral striatum during reward anticipation tasks (such as the Monetary‐Incentive‐Delay [MID] task). However, no prior research has applied either of these paradigms in medication‐naïve adults with ADHD, nor have these been implemented in an intrasubject manner. Methods: The sample consisted of 19 medication‐naïve adults with ADHD and 19 control subjects. Main group analyses were based on individually defined regions of interest: the IFG and the VStr for the Go‐NoGo and the MID task respectively. In addition, we analyzed the correlation between the two measures, as well as between these measures and the clinical symptoms of ADHD. Results: We observed reduced bilateral VStr activity in adults with ADHD during reward anticipation. No differences were detected in IFG activation on the Go‐NoGo paradigm. Correlation analyses suggest that the two tasks are independent at a neural level, but are related behaviorally in terms of the variability of the performance reaction time. Activity in the bilateral VStr but not in the IFG was associated negatively with symptoms of hyperactivity/impulsivity. Conclusions: Results underline the implication of the reward system in ADHD adult pathophysiology and suggest that frontal abnormalities during response inhibition performance may not be such a pivotal aspect of the phenotype in adulthood. In addition, our findings point toward response variability as a core feature of the disorder. Hum Brain Mapp 33:2350–2361, 2012.

Validity of the Adult ADHD Self-Report Scale (ASRS) as a screener for adult ADHD in treatment seeking substance use disorder patients

BACKGROUND To detect attention deficit hyperactivity disorder (ADHD) in treatment seeking substance use disorders (SUD) patients, a valid screening instrument is needed. OBJECTIVES To test the performance of the Adult ADHD Self-Report Scale V 1.1(ASRS) for adult ADHD in an international sample of treatment seeking SUD patients for DSM-IV-TR; for the proposed DSM-5 criteria; in different subpopulations, at intake and 1-2 weeks after intake; using different scoring algorithms; and different externalizing disorders as external criterion (including adult ADHD, bipolar disorder, antisocial and borderline personality disorder). METHODS In 1138 treatment seeking SUD subjects, ASRS performance was determined using diagnoses based on Conners Adult ADHD Diagnostic Interview for DSM-IV (CAADID) as gold standard. RESULTS The prevalence of adult ADHD was 13.0% (95% CI: 11.0-15.0%). The overall positive predictive value (PPV) of the ASRS was 0.26 (95% CI: 0.22-0.30), the negative predictive value (NPV) was 0.97 (95% CI: 0.96-0.98). The sensitivity (0.84, 95% CI: 0.76-0.88) and specificity (0.66, 95% CI: 0.63-0.69) measured at admission were similar to the sensitivity (0.88, 95% CI: 0.83-0.93) and specificity (0.67, 95% CI: 0.64-0.70) measured 2 weeks after admission. Sensitivity was similar, but specificity was significantly better in patients with alcohol compared to (illicit) drugs as the primary substance of abuse (0.76 vs. 0.56). ASRS was not a good screener for externalizing disorders other than ADHD. CONCLUSIONS The ASRS is a sensitive screener for identifying possible ADHD cases with very few missed cases among those screening negative in this population.

Predictors of treatment outcome in adults with ADHD treated with OROS® methylphenidate

BACKGROUND We conducted a post-hoc analysis of the Long-Acting MethylpheniDate in Adult attention-deficit hyperactivity disorder (LAMDA) study to investigate predictors of response in adults with ADHD randomly assigned to Osmotic Release Oral System (OROS)(®)-methylphenidate hydrochloride (MPH) 18, 36 or 72 mg or placebo. METHODS LAMDA comprised a 5-week, double-blind (DB) period, followed by a 7-week, open-label (OL) period. A post-hoc analysis of covariance and a logistic regression analysis were undertaken to detect whether specific baseline parameters or overall treatment compliance during the double-blind phase contributed to response. The initial model included all covariates as independent variables; a backward stepwise selection method was used, with stay criteria of p<0.10. Six outcomes were considered: change from baseline CAARS:O-SV (physician-rated) and CAARS:S-S (self-report) scores at DB and OL end points, and response rate (≥30% decrease in CAARS:O-SV score from baseline) and normalization of CAARS:O-SV score at DB end point. RESULTS Taking into account a significant effect of OROS(®)-MPH treatment versus placebo in the original analysis (p≤0.015), across the outcomes considered in this post-hoc analysis, higher baseline CAARS scores were most strongly predictive of superior outcomes. Male gender and lower academic achievement were also predictive for improved results with certain outcomes. CONCLUSIONS Several baseline factors may help to predict better treatment outcomes in adults receiving OROS(®)-MPH; however, further research is required to confirm these findings and examine their neurobiological underpinnings.

Laminar thickness alterations in the fronto-parietal cortical mantle of patients with attention-deficit/hyperactivity disorder.

Although Attention-Deficit/Hyperactivity Disorder (ADHD) was initially regarded as a disorder exclusive to childhood, nowadays its prevalence in adulthood is well established. The development of novel techniques for quantifying the thickness of the cerebral mantle allows the further exploration of the neuroanatomical profiles underlying the child and adult form of the disorder. To examine the cortical mantle in children and adults with ADHD, we applied a vertex-wise analysis of cortical thickness to anatomical brain MRI scans acquired from children with (n = 43) and without ADHD (n = 41), as well as a group of adult neurotypical individuals (n = 31), adult patients with a history of stimulant treatment (n = 31) and medication-naïve adults with ADHD (n = 24). We observed several clusters of reduced laminar cortical thickness in ADHD patients in comparison to neurotypical individuals. These differences were primarily located in the dorsal attention network, including the bilateral inferior and superior parietal cortex and a section of the frontal cortex (centered on the superior frontal and precentral gyrus bilaterally). Further laminar thickness deficits were observed in the bilateral orbitofrontal cortex and medial occipital cortex. The deficits in the cortical surface were especially pronounced in the child sample, while adult patients showed a more typical laminar thickness across the cerebral mantle. These findings show that the neuroanatomical profile of ADHD, especially the childhood form of the disorder, involves robust alterations in the cortical mantle, which are most prominent in brain regions subserving attentional processing.

Training‐induced neuroanatomical plasticity in ADHD: A tensor‐based morphometric study

Experience‐based neuroplasticity has typically been associated with functional changes, but growing evidence indicates that training can also render dynamic structural alterations in the brain. Although research on training‐induced morphological plasticity has consistently demonstrated rapid increases of gray matter volume in task‐related regions, no studies have examined if local volumetric reductions in gray matter associated with certain psychiatric disorders may be reversible by adequate training. We aimed to assess whether a training program applied to ADHD patients can contravene some of the associated neuroanatomical alterations. High‐resolution anatomical scans were acquired before and after the training period, and a whole‐brain tensor‐based morphometric approach was applied to extract a voxel‐wise estimation of longitudinal changes in regional gray matter volume. Our results show focal volumetric gray matter increases in bilateral middle frontal cortex and right inferior–posterior cerebellum after cognitive training compared with the ADHD control group. The extent of gray matter volume increase in the inferior–posterior cerebellum was associated with attentional performance. These findings illustrate the capacity of the nervous system for rapid morphological adjustments in response to environmental triggers. Moreover, the dorsolateral prefrontal cortex and cerebellum are commonly considered sites of volumetric reduction in ADHD, and the inferior–posterior lobule of the cerebellum is associated with progressive symptom‐related volume loss. Hence, the clusters of volumetric change observed in our study were confined to structures typically characterized by volume reduction in ADHD patients, providing preliminary indications that cognitive training may contravene some of the neuroanatomical deficits associated with the disorder. Hum Brain Mapp, 2010.

Achieving remission as a routine goal of pharmacotherapy in attention-deficit hyperactivity disorder.

Remission should be the goal of attention-deficit hyperactivity disorder (ADHD) treatment. However, there is no universally accepted definition of remission in ADHD, although clinical studies use a number of criteria. This article examines current research into the concept of remission in ADHD by reviewing the literature for definition and achievement of remission in children and adults with ADHD. Results demonstrate that the concept of remission in ADHD has been proposed by several study groups, using thresholds of validated rating scales to indicate syndromic, symptomatic and functional remission. Several studies have demonstrated the achievement of remission in ADHD children utilizing methylphenidate delivered by an osmotic, controlled-release formulation (OROS®) and atomoxetine. However, none has defined a time period over which these criteria must be met for an individual with ADHD to be considered ‘in remission’. Standardized remission criteria in ADHD will provide a tool for assessing the effectiveness of treatments for ADHD, and raise treatment standards.

The International ADHD in Substance Use Disorders Prevalence (IASP) study: Background, methods and study population

Attention deficit/hyperactivity disorder (ADHD) is an increasingly recognized comorbid condition in subjects with substance use disorders (SUDs).

Maintenance of response after open-label treatment with atomoxetine hydrochloride in international European and non-European adult outpatients with attention-deficit/hyperactivity disorder: a placebo-controlled, randomised withdrawal study

Background and Objectives:We evaluated maintenance of response to atomoxetine during a 25-week, double-blind, placebo-controlled, randomised withdrawal period in adults with attention-deficit/hyperactivity disorder (ADHD) who previously responded to atomoxetine during a 12 week open-label treatment period and maintained that response during a 12-week double-blind maintenance period. Methods: Patients (N = 2017), 18 to 50 years of age, diagnosed with ADHD from 152 outpatient sites in 18 countries received 12 weeks of open-label atomoxetine (40-100 mg/day) followed by 12 weeks of double-blind maintenance (80 or 100 mg/day). Responders were randomized to atomoxetine (N = 266) or placebo (N = 258) for 25-weeks of double-blind treatment. The percentage of patients with a reduction .30% in their baseline Conners�f ADHD Rating Scale Investigator-Rated: Screening Version (CAARS-Inv:SV) total score and a score of .3 on the Clinical Global Impression ADHD-Severity (CGIADHD- S) after 25 weeks was compared between treatment groups with a Fisher�fs exact test. Mean changes from baseline in the CAARS-Inv:SV and Adult Attention-Deficit/Hyperactivity Disorder Quality of Life (AAQoL) were analysed. Results: Most patients enrolled (60%) were from Europe. More atomoxetine- than placebo- treated patients maintained a satisfactory response postrandomisation (64.3% vs. 50.0%; p <.001). Time-to-relapse was significantly longer for atomoxetine than placebo (p = .004). Atomoxetine maintained greater improvements in ADHD symptoms compared with placebo (LS mean worsening in the CAARS-Inv:SV total score was 0.9 vs. 4.8 [p <.001] and in the CGI-ADHD-S rating was 0.0 vs. 0.5 [p <.001]). These results were supported by self- or observer- rated measures. Lastly, atomoxetine maintained greater improvements in quality of life compared with placebo (AAQoL total score was 0.4 vs. -4.0; p = .002). Conclusions: This study demonstrated that atomoxetine was superior to placebo in maintaining significantly greater treatment responses for up to 1 year in adults with ADHD.