Lizanne Schweren

Multicenter Voxel-Based Morphometry Mega-Analysis of Structural Brain Scans in Obsessive-Compulsive Disorder

OBJECTIVE Results from structural neuroimaging studies of obsessive-compulsive disorder (OCD) have been only partially consistent. The authors sought to assess regional gray and white matter volume differences between large samples of OCD patients and healthy comparison subjects and their relation with demographic and clinical variables. METHOD A multicenter voxel-based morphometry mega-analysis was performed on 1.5-T structural T1-weighted MRI scans derived from the International OCD Brain Imaging Consortium. Regional gray and white matter brain volumes were compared between 412 adult OCD patients and 368 healthy subjects. RESULTS Relative to healthy comparison subjects, OCD patients had significantly smaller volumes of frontal gray and white matter bilaterally, including the dorsomedial prefrontal cortex, the anterior cingulate cortex, and the inferior frontal gyrus extending to the anterior insula. Patients also showed greater cerebellar gray matter volume bilaterally compared with healthy subjects. Group differences in frontal gray and white matter volume were significant after correction for multiple comparisons. Additionally, group-by-age interactions were observed in the putamen, insula, and orbitofrontal cortex (indicating relative preservation of volume in patients compared with healthy subjects with increasing age) and in the temporal cortex bilaterally (indicating a relative loss of volume in patients compared with healthy subjects with increasing age). CONCLUSIONS These findings partially support the prevailing fronto-striatal models of OCD and offer additional insights into the neuroanatomy of the disorder that were not apparent from previous smaller studies. The group-by-age interaction effects in orbitofrontal-striatal and (para)limbic brain regions may be the result of altered neuroplasticity associated with chronic compulsive behaviors, anxiety, or compensatory processes related to cognitive dysfunction.

Developmentally Stable Whole-Brain Volume Reductions and Developmentally Sensitive Caudate and Putamen Volume Alterations in Those With Attention-Deficit/Hyperactivity Disorder and Their Unaffected Siblings

IMPORTANCE Attention-deficit/hyperactivity disorder (ADHD) is a heritable neurodevelopmental disorder. It has been linked to reductions in total brain volume and subcortical abnormalities. However, owing to heterogeneity within and between studies and limited sample sizes, findings on the neuroanatomical substrates of ADHD have shown considerable variability. Moreover, it remains unclear whether neuroanatomical alterations linked to ADHD are also present in the unaffected siblings of those with ADHD. OBJECTIVE To examine whether ADHD is linked to alterations in whole-brain and subcortical volumes and to study familial underpinnings of brain volumetric alterations in ADHD. DESIGN, SETTING, AND PARTICIPANTS In this cross-sectional study, we included participants from the large and carefully phenotyped Dutch NeuroIMAGE sample (collected from September 2009-December 2012) consisting of 307 participants with ADHD, 169 of their unaffected siblings, and 196 typically developing control individuals (mean age, 17.21 years; age range, 8-30 years). MAIN OUTCOMES AND MEASURES Whole-brain volumes (total brain and gray and white matter volumes) and volumes of subcortical regions (nucleus accumbens, amygdala, caudate nucleus, globus pallidus, hippocampus, putamen, thalamus, and brainstem) were derived from structural magnetic resonance imaging scans using automated tissue segmentation. RESULTS Regression analyses revealed that relative to control individuals, participants with ADHD had a 2.5% smaller total brain (β = -31.92; 95% CI, -52.69 to -11.16; P = .0027) and a 3% smaller total gray matter volume (β = -22.51; 95% CI, -35.07 to -9.96; P = .0005), while total white matter volume was unaltered (β = -10.10; 95% CI, -20.73 to 0.53; P = .06). Unaffected siblings had total brain and total gray matter volumes intermediate to participants with ADHD and control individuals. Significant age-by-diagnosis interactions showed that older age was linked to smaller caudate (P < .001) and putamen (P = .01) volumes (both corrected for total brain volume) in control individuals, whereas age was unrelated to these volumes in participants with ADHD and their unaffected siblings. Attention-deficit/hyperactivity disorder was not significantly related to the other subcortical volumes. CONCLUSIONS AND RELEVANCE Global differences in gray matter volume may be due to alterations in the general mechanisms underlying normal brain development in ADHD. The age-by-diagnosis interaction in the caudate and putamen supports the relevance of different brain developmental trajectories in participants with ADHD vs control individuals and supports the role of subcortical basal ganglia alterations in the pathophysiology of ADHD. Alterations in total gray matter and caudate and putamen volumes in unaffected siblings suggest that these volumes are linked to familial risk for ADHD.

MR imaging of the effects of methylphenidate on brain structure and function in Attention-Deficit/Hyperactivity Disorder

Methylphenidate is the first-choice pharmacological intervention for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD). The pharmacological and behavioral effects of methylphenidate are well described, but less is known about neurochemical brain changes induced by methylphenidate. This level of analysis may be informative on how the behavioral effects of methylphenidate are established. This paper reviews structural and functional MRI studies that have investigated effects of methylphenidate in children with ADHD. Structural MRI studies provide evidence that long-term stimulant treatment may normalize structural brain changes found in the white matter, the anterior cingulate cortex, the thalamus, and the cerebellum in ADHD. Moreover, preliminary evidence suggests that methylphenidate treatment may normalize the trajectory of cortical development in ADHD. Functional MRI has provided evidence that methylphenidate administration has acute effects on brain functioning, and even suggests that methylphenidate may normalize brain activation patterns as well as functional connectivity in children with ADHD during cognitive control, attention, and during rest. The effects of methylphenidate on the developing brain appear highly specific and dependent on numerous factors, including biological factors such as genetic predispositions, subject-related factors such as age and symptom severity, and task-related factors such as task difficulty. Future studies on structural and functional brain changes in ADHD may benefit from inclusion strategies guided by current medication status and medication history. Further studies on the effects of methylphenidate treatment on structural and functional MRI parameters are needed to address unresolved issues of the long-term effects of treatment, as well as the mechanism through which medication-induced brain changes bring about clinical improvement.

Brain Correlates of the Interaction Between 5-HTTLPR and Psychosocial Stress Mediating Attention Deficit Hyperactivity Disorder Severity

OBJECTIVE The serotonin transporter 5-HTTLPR genotype has been found to moderate the effect of stress on severity of attention deficit hyperactivity disorder (ADHD), with stronger effects of stress in carriers of the short allele than in individuals homozygous for the long allele. The underlying neurobiological mechanism of this gene-environment interaction in ADHD is unknown. The authors aimed to determine whether 5-HTTLPR moderates the effect of stress on brain gray matter volume and, if so, which brain regions mediate the effect of this gene-environment interaction on ADHD severity. METHOD Structural MRI, 5-HTTLPR genotype, and stress exposure questionnaire data were available for 701 adolescents and young adults participating in the multicenter ADHD cohort NeuroIMAGE study (from 385 families; 291 with ADHD, 78 with subthreshold ADHD, 332 healthy comparison subjects; 55.8% male; average age: 17.0 years). ADHD symptom count was determined through multi-informant questionnaires. For the analysis, a whole-brain voxel-based morphometry approach was combined with mediation analysis. RESULTS Stress exposure was associated with significantly less gray matter volume in the precentral gyrus, middle and superior frontal gyri, frontal pole, and cingulate gyrus in S-allele carriers compared with participants homozygous for the l-allele. The association of this gene-environment interaction with ADHD symptom count was mediated by gray matter volume in the frontal pole and anterior cingulate gyrus. CONCLUSIONS 5-HTTLPR genotype moderates the effect of stress on brain regions involved in social cognitive processing and cognitive control. Specifically, regions important for cognitive control link this gene-environment interaction to ADHD severity.

Assessment of Symptom Network Density as a Prognostic Marker of Treatment Response in Adolescent Depression

One in 4 adolescents with depression does not respond favorably to treatment.1 Prognostic markers to identify this nonresponder group are lacking and urgently needed.2 It has been suggested that the network structure of depressive symptoms (ie, group-level covariance or connectivity between symptoms) may be informative in this regard.3 Intuitively, one may expect that more densely connected networks would be more inclined to result in negative spirals (eg, sleeplessness causes an individual to be too tired to go out, which leads to a lack of friends, resulting in sadness) and therefore more liable to nonresponse. An influential naturalistic study by van Borkulo et al published in JAMA Psychiatry3 reported that adult patients with depression who continue to experience problems in subsequent years have more densely connected networks at baseline than patients who later recover. Here, we performed a conceptual replication of that study in adolescents with depression who participated in a psychological treatment trial. We tested whether network characteristics at baseline were prognostic for long-term outcomes.1

Stimulant treatment history predicts frontal-striatal structural connectivity in adolescents with attention-deficit/hyperactivity disorder

Diffusion tensor imaging (DTI) has revealed white matter abnormalities in individuals with attention-deficit/hyperactivity disorder (ADHD). Stimulant treatment may affect such abnormalities. The current study investigated associations between long-term stimulant treatment and white matter integrity within the frontal-striatal and mesolimbic pathways, in a large sample of children, adolescents and young adults with ADHD. Participants with ADHD (N=172; mean age 17, range 9-26) underwent diffusion-weighted MRI scanning, along with an age- and gendermatched group of 96 control participants. Five study-specific white matter tract masks (orbitofrontal-striatal, orbitofrontal-amygdalar, amygdalar-striatal, dorsolateral-prefrontal-striatal and medialprefrontal-striatal) were created. First we analyzed case-control differences in fractional anisotropy (FA) and mean diffusivity (MD) within each tract. Second, FA and MD in each tract was predicted from cumulative stimulant intake within the ADHD group. After correction for multiple testing, participants with ADHD showed reduced FA in the orbitofrontal-striatal pathway (p=0.010, effect size=0.269). Within the ADHD group, higher cumulative stimulant intake was associated with lower MD in the same pathway (p=0.011, effect size=-0.164), but not with FA. The association between stimulant treatment and orbitofrontal-striatal MD was of modest effect size. It fell short of significance after adding ADHD severity or ADHD type to the model (p=0.036 and p=0.094, respectively), while the effect size changed little. Our findings are compatible with stimulant treatment enhancing orbitofrontal-striatal white matter connectivity, and emphasize the importance of the orbitofrontal cortex and its connections in ADHD. Longitudinal studies including a drug-naïve baseline assessment are needed to distinguish between-subject variability in ADHD severity from treatment effects.

An update on the safety of psychostimulants for the treatment of attention-deficit/hyperactivity disorder

ABSTRACT Introduction: Methylphenidate is the first-line pharmacological treatment of attention-deficit/hyperactivity disorder (ADHD). Although methylphenidate has a well-established evidence base for treating ADHD, its long-term benefits are unclear. Areas covered: Physical adverse effects, psychiatric adverse events and brain development Expert opinion: Some physical adverse events have been described (e.g. sleep disturbances, growth reduction, loss of appetite), although most are of transient nature. Psychiatric adverse events seem more related to the diagnosis ADHD itself, and not stimulant treatment. Concluding, short-to-mid-term use (i.e., up to 2 years) stimulants are relatively safe, but much less is known about longer-term efficacy and safety of these drugs.

Stimulant Treatment Trajectories Are Associated With Neural Reward Processing in Attention-Deficit/Hyperactivity Disorder

OBJECTIVE The past decades have seen a surge in stimulant prescriptions for the treatment of attention-deficit/hyperactivity disorder (ADHD). Stimulants acutely alleviate symptoms and cognitive deficits associated with ADHD by modulating striatal dopamine neurotransmission and induce therapeutic changes in brain activation patterns. Long-term functional changes after treatment are unknown, as long-term studies are scarce and have focused on brain structure. In this observational study (2009-2012), we investigated associations between lifetime stimulant treatment history and neural activity during reward processing. METHODS Participants fulfilling DSM-5 criteria for ADHD (N = 269) were classified according to stimulant treatment trajectory. Of those, 124 performed a monetary incentive delay task during magnetic resonance imaging, all in their nonmedicated state (nEARLY&INTENSE = 51; nLATE&MODERATE = 49; nEARLY&MODERATE = 9; nNAIVE = 15; mean age = 17.4 years; range, 10-26 years). Whole-brain analyses were performed with additional focus on the striatum, concentrating on the 2 largest treatment groups. RESULTS Compared to the late-and-moderate treatment group, the early-and-intense treatment group showed more activation in the supplementary motor area and dorsal anterior cingulate cortex (SMA/dACC) during reward outcome (cluster size = 8,696 mm³; PCLUSTER < .001). SMA/dACC activation of the control group fell in between the 2 treatment groups. Treatment history was not associated with striatal activation during reward processing. CONCLUSIONS Our findings are compatible with previous reports of acute increases of SMA/dACC activity in individuals with ADHD after stimulant administration. Higher SMA/dACC activity may indicate that patients with a history of intensive stimulant treatment, but currently off medication, recruit brain regions for cognitive control and/or decision-making upon being rewarded. No striatal or structural changes were found.

YICAP/ECAP international young investigators paper and grant writing workshop

The ‘‘YICAP/ECAP International Young Investigators Paper and Grant Writing Workshop’’ in Rees (September 18–19 2014), Germany, brought sixteen young researchers from ten different institutions in three European countries together with editors from European Child & Adolescent Psychiatry (ECAP). YICAP (Young Investigators in Child and Adolescent Psychiatry), a German organization for young researchers, had organized the meeting together with Prof. Hebebrand as the Editor-in-Chief of ECAP. The meeting was kindly supported by the Karl Moik Foundation for Child and Adolescent Psychiatry, Aachen, Germany and Prof. Hebebrand. It was designed as a follow-up to a writing workshop in Berlin in March 2014, now including also participants from the Netherlands and Finland. The first day started with a warm welcome by Jochen Seitz, one of the speakers of YICAP, followed by a summary of the topics covered during the Berlin meeting. In an excellent overview, he pointed out the importance of abstract and title and the challenge to focus on the main findings, which was complemented by participants’ writing experiences after the first workshop. Indeed, it appeared that several recommendations had found their way into the participants’ work and had led to improvements, especially regarding time-management techniques and ways to counter writer’s block. Prior to the meeting in Rees, participants had shared their work in progress in small groups of three or four participants. Next, these papers and grants were discussed in two intense peer-to-peer supervision sessions. Similar to the first workshop, this format was experienced as extremely valuable. Feedback from peers in the broader field adds new perspectives and discloses strengths and weaknesses that may be overlooked by members of the own working group. At the same time peerto-peer supervision provides an open and constructive environment to discuss potential problems or errors with peers at a similar stage in their scientific careers. In between the two sessions, Georg von Polier, also speaker of YICAP, went deeper into the art of writing a sound and structured discussion. He focused on the delicate balance between correct and professional interpretation of results on the one hand and trying to ‘‘sell’’ the paper on the other. After a stimulating program of alternating input talks and active discussion sessions, the day ended with a brainstorming round table discussion concerning proven procedures and new ideas for future workshops, focusing on building a European Young Investigators Infrastructure in the form of an annual ESCAP Academy. In the evening, participants of the workshop together with ECAP editors were gratefully invited to Prof. Hebebrand’s house in Rees for joint cooking and eating. As participants and editors worked together hand in hand, guided by Jochen Seitz and Georg von Polier, an astonishingly sophisticated meal was prepared and consumed with intense discussions until late in the evening—many thanks again! The next day the workshop participants met with three renowned editors from ECAP: Prof. Hebebrand from Essen, Germany, Prof. Hoekstra from Groningen, The Netherlands and Prof. Polanczyk from Porto Alegre, Brazil. The editors provided the young researchers with highly appreciated reports of their own research careers, advice for career management and—most valuable—pointed out Communications of the European Society for Child and Adolescent Psychiatry