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Storebø OJ, Storm MRO, Pereira Ribeiro J, Skoog M, Groth C, Callesen HE, Schaug JP, Darling Rasmussen P, Huus CML, Zwi M, Kirubakaran R, Simonsen E, Gluud C. Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD). Cochrane Database Syst Rev 2023; 3:CD009885. [PMID: 36971690 PMCID: PMC10042435 DOI: 10.1002/14651858.cd009885.pub3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
BACKGROUND Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed and treated psychiatric disorders in childhood. Typically, children and adolescents with ADHD find it difficult to pay attention and they are hyperactive and impulsive. Methylphenidate is the psychostimulant most often prescribed, but the evidence on benefits and harms is uncertain. This is an update of our comprehensive systematic review on benefits and harms published in 2015. OBJECTIVES To assess the beneficial and harmful effects of methylphenidate for children and adolescents with ADHD. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, three other databases and two trials registers up to March 2022. In addition, we checked reference lists and requested published and unpublished data from manufacturers of methylphenidate. SELECTION CRITERIA We included all randomised clinical trials (RCTs) comparing methylphenidate versus placebo or no intervention in children and adolescents aged 18 years and younger with a diagnosis of ADHD. The search was not limited by publication year or language, but trial inclusion required that 75% or more of participants had a normal intellectual quotient (IQ > 70). We assessed two primary outcomes, ADHD symptoms and serious adverse events, and three secondary outcomes, adverse events considered non-serious, general behaviour, and quality of life. DATA COLLECTION AND ANALYSIS Two review authors independently conducted data extraction and risk of bias assessment for each trial. Six review authors including two review authors from the original publication participated in the update in 2022. We used standard Cochrane methodological procedures. Data from parallel-group trials and first-period data from cross-over trials formed the basis of our primary analyses. We undertook separate analyses using end-of-last period data from cross-over trials. We used Trial Sequential Analyses (TSA) to control for type I (5%) and type II (20%) errors, and we assessed and downgraded evidence according to the GRADE approach. MAIN RESULTS We included 212 trials (16,302 participants randomised); 55 parallel-group trials (8104 participants randomised), and 156 cross-over trials (8033 participants randomised) as well as one trial with a parallel phase (114 participants randomised) and a cross-over phase (165 participants randomised). The mean age of participants was 9.8 years ranging from 3 to 18 years (two trials from 3 to 21 years). The male-female ratio was 3:1. Most trials were carried out in high-income countries, and 86/212 included trials (41%) were funded or partly funded by the pharmaceutical industry. Methylphenidate treatment duration ranged from 1 to 425 days, with a mean duration of 28.8 days. Trials compared methylphenidate with placebo (200 trials) and with no intervention (12 trials). Only 165/212 trials included usable data on one or more outcomes from 14,271 participants. Of the 212 trials, we assessed 191 at high risk of bias and 21 at low risk of bias. If, however, deblinding of methylphenidate due to typical adverse events is considered, then all 212 trials were at high risk of bias. PRIMARY OUTCOMES methylphenidate versus placebo or no intervention may improve teacher-rated ADHD symptoms (standardised mean difference (SMD) -0.74, 95% confidence interval (CI) -0.88 to -0.61; I² = 38%; 21 trials; 1728 participants; very low-certainty evidence). This corresponds to a mean difference (MD) of -10.58 (95% CI -12.58 to -8.72) on the ADHD Rating Scale (ADHD-RS; range 0 to 72 points). The minimal clinically relevant difference is considered to be a change of 6.6 points on the ADHD-RS. Methylphenidate may not affect serious adverse events (risk ratio (RR) 0.80, 95% CI 0.39 to 1.67; I² = 0%; 26 trials, 3673 participants; very low-certainty evidence). The TSA-adjusted intervention effect was RR 0.91 (CI 0.31 to 2.68). SECONDARY OUTCOMES methylphenidate may cause more adverse events considered non-serious versus placebo or no intervention (RR 1.23, 95% CI 1.11 to 1.37; I² = 72%; 35 trials 5342 participants; very low-certainty evidence). The TSA-adjusted intervention effect was RR 1.22 (CI 1.08 to 1.43). Methylphenidate may improve teacher-rated general behaviour versus placebo (SMD -0.62, 95% CI -0.91 to -0.33; I² = 68%; 7 trials 792 participants; very low-certainty evidence), but may not affect quality of life (SMD 0.40, 95% CI -0.03 to 0.83; I² = 81%; 4 trials, 608 participants; very low-certainty evidence). AUTHORS' CONCLUSIONS The majority of our conclusions from the 2015 version of this review still apply. Our updated meta-analyses suggest that methylphenidate versus placebo or no-intervention may improve teacher-rated ADHD symptoms and general behaviour in children and adolescents with ADHD. There may be no effects on serious adverse events and quality of life. Methylphenidate may be associated with an increased risk of adverse events considered non-serious, such as sleep problems and decreased appetite. However, the certainty of the evidence for all outcomes is very low and therefore the true magnitude of effects remain unclear. Due to the frequency of non-serious adverse events associated with methylphenidate, the blinding of participants and outcome assessors is particularly challenging. To accommodate this challenge, an active placebo should be sought and utilised. It may be difficult to find such a drug, but identifying a substance that could mimic the easily recognised adverse effects of methylphenidate would avert the unblinding that detrimentally affects current randomised trials. Future systematic reviews should investigate the subgroups of patients with ADHD that may benefit most and least from methylphenidate. This could be done with individual participant data to investigate predictors and modifiers like age, comorbidity, and ADHD subtypes.
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Affiliation(s)
- Ole Jakob Storebø
- Psychiatric Research Unit, Region Zealand Psychiatry, Slagelse, Denmark
- Child and Adolescent Psychiatric Department, Region Zealand, Roskilde, Denmark
- Department of Psychology, University of Southern Denmark, Odense, Denmark
| | | | | | - Maria Skoog
- Clinical Study Support, Clinical Studies Sweden - Forum South, Lund, Sweden
| | - Camilla Groth
- Pediatric Department, Herlev University Hospital, Herlev, Denmark
| | | | | | | | | | - Morris Zwi
- Islington Child and Adolescent Mental Health Service, Whittington Health, London, UK
| | - Richard Kirubakaran
- Cochrane India-CMC Vellore Affiliate, Prof. BV Moses Centre for Evidence Informed Healthcare and Health Policy, Christian Medical College, Vellore, India
| | - Erik Simonsen
- Research Unit, Mental Health services, Region Zealand Psychiatry, Roskilde, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christian Gluud
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, The Capital Region, Copenhagen University Hospital ─ Rigshospitalet, Copenhagen, Denmark
- Department of Regional Health Research, The Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
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Schrantee A, Tamminga HGH, Bouziane C, Bottelier MA, Bron EE, Mutsaerts HJMM, Zwinderman AH, Groote IR, Rombouts SARB, Lindauer RJL, Klein S, Niessen WJ, Opmeer BC, Boer F, Lucassen PJ, Andersen SL, Geurts HM, Reneman L. Age-Dependent Effects of Methylphenidate on the Human Dopaminergic System in Young vs Adult Patients With Attention-Deficit/Hyperactivity Disorder: A Randomized Clinical Trial. JAMA Psychiatry 2016; 73:955-62. [PMID: 27487479 PMCID: PMC5267166 DOI: 10.1001/jamapsychiatry.2016.1572] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
IMPORTANCE Although numerous children receive methylphenidate hydrochloride for the treatment of attention-deficit/hyperactivity disorder (ADHD), little is known about age-dependent and possibly lasting effects of methylphenidate on the human dopaminergic system. OBJECTIVES To determine whether the effects of methylphenidate on the dopaminergic system are modified by age and to test the hypothesis that methylphenidate treatment of young but not adult patients with ADHD induces lasting effects on the cerebral blood flow response to dopamine challenge, a noninvasive probe for dopamine function. DESIGN, SETTING, AND PARTICIPANTS A randomized, double-blind, placebo-controlled trial (Effects of Psychotropic Drugs on Developing Brain-Methylphenidate) among ADHD referral centers in the greater Amsterdam area in the Netherlands between June 1, 2011, and June 15, 2015. Additional inclusion criteria were male sex, age 10 to 12 years or 23 to 40 years, and stimulant treatment-naive status. INTERVENTIONS Treatment with either methylphenidate or a matched placebo for 16 weeks. MAIN OUTCOMES AND MEASURES Change in the cerebral blood flow response to an acute challenge with methylphenidate, noninvasively assessed using pharmacological magnetic resonance imaging, between baseline and 1 week after treatment. Data were analyzed using intent-to-treat analyses. RESULTS Among 131 individuals screened for eligibility, 99 patients met DSM-IV criteria for ADHD, and 50 participants were randomized to receive methylphenidate and 49 to placebo. Sixteen weeks of methylphenidate treatment increased the cerebral blood flow response to methylphenidate within the thalamus (mean difference, 6.5; 95% CI, 0.4-12.6; P = .04) of children aged 10 to 12 years old but not in adults or in the placebo group. In the striatum, the methylphenidate condition differed significantly from placebo in children but not in adults (mean difference, 7.7; 95% CI, 0.7-14.8; P = .03). CONCLUSIONS AND RELEVANCE We confirm preclinical data and demonstrate age-dependent effects of methylphenidate treatment on human extracellular dopamine striatal-thalamic circuitry. Given its societal relevance, these data warrant replication in larger groups with longer follow-up. TRIAL REGISTRATION identifier: NL34509.000.10 and trialregister.nl identifier: NTR3103.
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Affiliation(s)
- Anouk Schrantee
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands2Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands3Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
| | - Hyke G. H. Tamminga
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands4d’Arc (Dutch Autism and Attention-Deficit/Hyperactivity Disorder Research Center), Department of Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
| | - Cheima Bouziane
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands2Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Marco A. Bottelier
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands5Department of Child and Adolescent Psychiatry, Triversum, Alkmaar, the Netherlands
| | - Esther E. Bron
- Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus Medical Center, Rotterdam, the Netherlands7Biomedical Imaging Group Rotterdam, Department of Radiology, Erasmus MC, Rotterdam, the Netherlands
| | - Henk-Jan M. M. Mutsaerts
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands2Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Aeilko H. Zwinderman
- Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Inge R. Groote
- Institute of Psychology, Department of Social Sciences, University of Oslo, Oslo, Norway
| | - Serge A. R. B. Rombouts
- Institute of Psychology, Leiden University, Leiden, the Netherlands11Department of Radiology, Leids Universitair Medisch Centrum, Leiden, the Netherlands
| | - Ramon J. L. Lindauer
- Department of Child and Adolescent Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands13De Bascule Academic Center for Child and Adolescent Psychiatry, Amsterdam, the Netherlands
| | - Stefan Klein
- Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Wiro J. Niessen
- Biomedical Imaging Group Rotterdam, Department of Medical Informatics, Erasmus Medical Center, Rotterdam, the Netherlands14Department of Imaging Physics, Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Brent C. Opmeer
- Clinical Research Unit, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Frits Boer
- Department of Child and Adolescent Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands13De Bascule Academic Center for Child and Adolescent Psychiatry, Amsterdam, the Netherlands
| | - Paul J. Lucassen
- Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Susan L. Andersen
- Department of Psychiatry, Harvard Medical School and McLean Hospital, Belmont, Massachusetts
| | - Hilde M. Geurts
- d’Arc (Dutch Autism and Attention-Deficit/Hyperactivity Disorder Research Center), Department of Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
| | - Liesbeth Reneman
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands2Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands3Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
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Storebø OJ, Ramstad E, Krogh HB, Nilausen TD, Skoog M, Holmskov M, Rosendal S, Groth C, Magnusson FL, Moreira‐Maia CR, Gillies D, Buch Rasmussen K, Gauci D, Zwi M, Kirubakaran R, Forsbøl B, Simonsen E, Gluud C. Methylphenidate for children and adolescents with attention deficit hyperactivity disorder (ADHD). Cochrane Database Syst Rev 2015; 2015:CD009885. [PMID: 26599576 PMCID: PMC8763351 DOI: 10.1002/14651858.cd009885.pub2] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Attention deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed and treated psychiatric disorders in childhood. Typically, children with ADHD find it difficult to pay attention, they are hyperactive and impulsive.Methylphenidate is the drug most often prescribed to treat children and adolescents with ADHD but, despite its widespread use, this is the first comprehensive systematic review of its benefits and harms. OBJECTIVES To assess the beneficial and harmful effects of methylphenidate for children and adolescents with ADHD. SEARCH METHODS In February 2015 we searched six databases (CENTRAL, Ovid MEDLINE, EMBASE, CINAHL, PsycINFO, Conference Proceedings Citations Index), and two trials registers. We checked for additional trials in the reference lists of relevant reviews and included trials. We contacted the pharmaceutical companies that manufacture methylphenidate to request published and unpublished data. SELECTION CRITERIA We included all randomised controlled trials (RCTs) comparing methylphenidate versus placebo or no intervention in children and adolescents aged 18 years and younger with a diagnosis of ADHD. At least 75% of participants needed to have an intellectual quotient of at least 70 (i.e. normal intellectual functioning). Outcomes assessed included ADHD symptoms, serious adverse events, non-serious adverse events, general behaviour and quality of life. DATA COLLECTION AND ANALYSIS Seventeen review authors participated in data extraction and risk of bias assessment, and two review authors independently performed all tasks. We used standard methodological procedures expected within Cochrane. Data from parallel-group trials and first period data from cross-over trials formed the basis of our primary analyses; separate analyses were undertaken using post-cross-over data from cross-over trials. We used Trial Sequential Analyses to control for type I (5%) and type II (20%) errors, and we assessed and downgraded evidence according to the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach for high risk of bias, imprecision, indirectness, heterogeneity and publication bias. MAIN RESULTS The studies.We included 38 parallel-group trials (5111 participants randomised) and 147 cross-over trials (7134 participants randomised). Participants included individuals of both sexes, at a boys-to-girls ratio of 5:1, and participants' ages ranged from 3 to 18 years across most studies (in two studies ages ranged from 3 to 21 years). The average age across all studies was 9.7 years. Most participants were from high-income countries.The duration of methylphenidate treatment ranged from 1 to 425 days, with an average duration of 75 days. Methylphenidate was compared to placebo (175 trials) or no intervention (10 trials). Risk of Bias.All 185 trials were assessed to be at high risk of bias. Primary outcomes. Methylphenidate may improve teacher-rated ADHD symptoms (standardised mean difference (SMD) -0.77, 95% confidence interval (CI) -0.90 to -0.64; 19 trials, 1698 participants; very low-quality evidence). This corresponds to a mean difference (MD) of -9.6 points (95% CI -13.75 to -6.38) on the ADHD Rating Scale (ADHD-RS; range 0 to 72 points; DuPaul 1991a). A change of 6.6 points on the ADHD-RS is considered clinically to represent the minimal relevant difference. There was no evidence that methylphenidate was associated with an increase in serious (e.g. life threatening) adverse events (risk ratio (RR) 0.98, 95% CI 0.44 to 2.22; 9 trials, 1532 participants; very low-quality evidence). The Trial Sequential Analysis-adjusted intervention effect was RR 0.91 (CI 0.02 to 33.2). SECONDARY OUTCOMES Among those prescribed methylphenidate, 526 per 1000 (range 448 to 615) experienced non-serious adverse events, compared with 408 per 1000 in the control group. This equates to a 29% increase in the overall risk of any non-serious adverse events (RR 1.29, 95% CI 1.10 to 1.51; 21 trials, 3132 participants; very low-quality evidence). The Trial Sequential Analysis-adjusted intervention effect was RR 1.29 (CI 1.06 to 1.56). The most common non-serious adverse events were sleep problems and decreased appetite. Children in the methylphenidate group were at 60% greater risk for trouble sleeping/sleep problems (RR 1.60, 95% CI 1.15 to 2.23; 13 trials, 2416 participants), and 266% greater risk for decreased appetite (RR 3.66, 95% CI 2.56 to 5.23; 16 trials, 2962 participants) than children in the control group.Teacher-rated general behaviour seemed to improve with methylphenidate (SMD -0.87, 95% CI -1.04 to -0.71; 5 trials, 668 participants; very low-quality evidence).A change of seven points on the Child Health Questionnaire (CHQ; range 0 to 100 points; Landgraf 1998) has been deemed a minimal clinically relevant difference. The change reported in a meta-analysis of three trials corresponds to a MD of 8.0 points (95% CI 5.49 to 10.46) on the CHQ, which suggests that methylphenidate may improve parent-reported quality of life (SMD 0.61, 95% CI 0.42 to 0.80; 3 trials, 514 participants; very low-quality evidence). AUTHORS' CONCLUSIONS The results of meta-analyses suggest that methylphenidate may improve teacher-reported ADHD symptoms, teacher-reported general behaviour, and parent-reported quality of life among children and adolescents diagnosed with ADHD. However, the low quality of the underpinning evidence means that we cannot be certain of the magnitude of the effects. Within the short follow-up periods typical of the included trials, there is some evidence that methylphenidate is associated with increased risk of non-serious adverse events, such as sleep problems and decreased appetite, but no evidence that it increases risk of serious adverse events.Better designed trials are needed to assess the benefits of methylphenidate. Given the frequency of non-serious adverse events associated with methylphenidate, the particular difficulties for blinding of participants and outcome assessors point to the advantage of large, 'nocebo tablet' controlled trials. These use a placebo-like substance that causes adverse events in the control arm that are comparable to those associated with methylphenidate. However, for ethical reasons, such trials should first be conducted with adults, who can give their informed consent.Future trials should publish depersonalised individual participant data and report all outcomes, including adverse events. This will enable researchers conducting systematic reviews to assess differences between intervention effects according to age, sex, comorbidity, type of ADHD and dose. Finally, the findings highlight the urgent need for large RCTs of non-pharmacological treatments.
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Affiliation(s)
- Ole Jakob Storebø
- Region ZealandChild and Adolescent Psychiatric DepartmentBirkevaenget 3RoskildeDenmark4300
- Region Zealand PsychiatryPsychiatric Research UnitSlagelseDenmark
- University of Southern DenmarkDepartment of Psychology, Faculty of Health ScienceCampusvej 55OdenseDenmark5230
| | - Erica Ramstad
- Region ZealandChild and Adolescent Psychiatric DepartmentBirkevaenget 3RoskildeDenmark4300
- Region Zealand PsychiatryPsychiatric Research UnitSlagelseDenmark
| | - Helle B. Krogh
- Region ZealandChild and Adolescent Psychiatric DepartmentBirkevaenget 3RoskildeDenmark4300
- Region Zealand PsychiatryPsychiatric Research UnitSlagelseDenmark
| | | | | | | | - Susanne Rosendal
- Psychiatric Centre North ZealandThe Capital Region of DenmarkDenmark
| | - Camilla Groth
- Herlev University HospitalPediatric DepartmentCapital RegionHerlevDenmark
| | | | - Carlos R Moreira‐Maia
- Federal University of Rio Grande do SulDepartment of PsychiatryRua Ramiro Barcelos, 2350‐2201APorto AlegreRSBrazil90035‐003
| | - Donna Gillies
- Western Sydney Local Health District ‐ Mental HealthCumberland HospitalLocked Bag 7118ParramattaNSWAustralia2124
| | | | - Dorothy Gauci
- Department of HealthDirectorate for Health Information and Research95 G'Mangia HillG'MangiaMaltaPTA 1313
| | - Morris Zwi
- Whittington HealthIslington Child and Adolescent Mental Health Service580 Holloway RoadLondonLondonUKN7 6LB
| | - Richard Kirubakaran
- Christian Medical CollegeCochrane South Asia, Prof. BV Moses Center for Evidence‐Informed Health Care and Health PolicyCarman Block II FloorCMC Campus, BagayamVelloreTamil NaduIndia632002
| | - Bente Forsbøl
- Psychiatric Department, Region ZealandChild and Adolescent Psychiatric ClinicHolbaekDenmark
| | - Erik Simonsen
- Region Zealand PsychiatryPsychiatric Research UnitSlagelseDenmark
- Copenhagen UniversityInstitute of Clinical Medicine, Faculty of Health and Medical SciencesCopenhagenDenmark
| | - Christian Gluud
- Copenhagen Trial Unit, Centre for Clinical Intervention Research, Department 7812, Rigshospitalet, Copenhagen University HospitalThe Cochrane Hepato‐Biliary GroupBlegdamsvej 9CopenhagenDenmarkDK‐2100
- Copenhagen University HospitalCopenhagen Trial Unit, Centre for Clinical Intervention ResearchCopenhagenDenmark
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Capp PK, Pearl PL, Conlon C. Methylphenidate HCl: therapy for attention deficit hyperactivity disorder. Expert Rev Neurother 2014; 5:325-31. [PMID: 15938665 DOI: 10.1586/14737175.5.3.325] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Methylphenidate is a first-line therapy for attention deficit hyperactivity disorder, the most prevalent neuropsychiatric disorder of childhood. The compound is a piperidine and the D-threo-isomer is considered the biologically active form. The compound is available in multiple short- and long-acting preparations, having different delivery systems leading to varying kinetics without clear superiority in efficacy or tolerability at the group level. Common adverse effects are insomnia, appetite disturbance, stomach ache, headache and dizziness. Its mechanism of action is linked to the monoamines dopamine and norepinephrine. The compound appears to predominantly increase the synaptic concentration of dopamine, presumably via inhibition of the dopamine transporter DAT1. There also appears to be effects on presynaptic vesicular trafficking and distribution of dopamine. Both immediate- and sustained-release preparations of methylphenidate have proven efficacy in children and adults with attention deficit hyperactivity disorder. Analysis of the National Institutes of Health-sponsored multimodal treatment study of attention deficit hyperactivity disorder supports a combined medication and behavioral therapy approach.
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Affiliation(s)
- Philip K Capp
- George Washington University, Department of Neurology, Children's National Medical Center, School of Medicine, Washington DC, USA
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Skokauskas N, Hitoshi K, Shuji H, Frodl T. Neuroimaging markers for the prediction of treatment response to Methylphenidate in ADHD. Eur J Paediatr Neurol 2013; 17:543-51. [PMID: 23672833 DOI: 10.1016/j.ejpn.2013.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 11/18/2012] [Accepted: 04/13/2013] [Indexed: 11/16/2022]
Abstract
BACKGROUND Attention Deficit Hyperactivity Disorder (ADHD) is one of the most prevalent mental disorders of childhood, which often continues into adulthood. Methylphenidate is one the most commonly used medication to treat ADHD, however up to 30% of patients do not respond to it. AIMS This paper aims to review studies, which employed neuroimaging to predict treatment response to Methylphenidate in ADHD. METHODS Systematic literature searches were performed using several databases. Selected articles had to describe an original study that identified neuroimaging markers for the prediction of treatment response to Methylphenidate in ADHD. RESULTS Eighty-three articles were found, of which twelve were selected for the present review. Several neuroimaging markers to predict response to MPH were suggested including DAT status, size of medial prefrontal cortex and corpus callosum. CONCLUSION Some promising findings have been identified and they should motivate additional work to establish more reliable neuroimaging markers of treatment response to MPH in ADHD.
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Affiliation(s)
- Norbert Skokauskas
- Department of Psychiatry, Trinity College Dublin, Ireland; Department of Psychiatry and Developmental Psychology, University of Nagoya, Japan; Department of Psychiatry, Children's University Hospital, Dublin, Ireland.
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McBain R, Norton DJ, Morris J, Yasamy MT, Betancourt TS. The role of health systems factors in facilitating access to psychotropic medicines: a cross-sectional analysis of the WHO-AIMS in 63 low- and middle-income countries. PLoS Med 2012; 9:e1001166. [PMID: 22303288 PMCID: PMC3269418 DOI: 10.1371/journal.pmed.1001166] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 12/14/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Neuropsychiatric conditions comprise 14% of the global burden of disease and 30% of all noncommunicable disease. Despite the existence of cost-effective interventions, including administration of psychotropic medicines, the number of persons who remain untreated is as high as 85% in low- and middle-income countries (LAMICs). While access to psychotropic medicines varies substantially across countries, no studies to date have empirically investigated potential health systems factors underlying this issue. METHODS AND FINDINGS This study uses a cross-sectional sample of 63 LAMICs and country regions to identify key health systems components associated with access to psychotropic medicines. Data from countries that completed the World Health Organization Assessment Instrument for Mental Health Systems (WHO-AIMS) were included in multiple regression analyses to investigate the role of five major mental health systems domains in shaping medicine availability and affordability. These domains are: mental health legislation, human rights implementations, mental health care financing, human resources, and the role of advocacy groups. Availability of psychotropic medicines was associated with features of all five mental health systems domains. Most notably, within the domain of mental health legislation, a comprehensive national mental health plan was associated with 15% greater availability; and in terms of advocacy groups, the participation of family-based organizations in the development of mental health legislation was associated with 17% greater availability. Only three measures were related with affordability of medicines to consumers: level of human resources, percentage of countries' health budget dedicated to mental health, and availability of mental health care in prisons. Controlling for country development, as measured by the Human Development Index, health systems features were associated with medicine availability but not affordability. CONCLUSIONS Results suggest that strengthening particular facets of mental health systems might improve availability of psychotropic medicines and that overall country development is associated with affordability.
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Affiliation(s)
- Ryan McBain
- Department of Global Health and Population, Harvard School of Public Health, Boston, Massachusetts, United States of America.
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Attention deficit/hyperactivity disorder: is there a correlation between dopamine transporter density and cerebral blood flow? Clin Nucl Med 2011; 36:656-60. [PMID: 21716015 DOI: 10.1097/rlu.0b013e318219b49d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Attention deficit/hyperactivity disorder (ADHD) is one of the most frequent behavioral problems in school-age children. Although the etiology remains unclear, the involvement of the dopaminergic system has been suggested by genetic studies that report an overexpression of the dopamine transporter (DAT) gene. In spite of these abnormalities being directly related to the decrease of dopamine (DA) in the striatum (STR), abnormalities in brain perfusion have also been observed in cortical-subcortical structures. Functional neuroimaging studies have suggested that the DA concentration may cause changes in the cerebral blood flow (CBF). The objective of our study was to evaluate the relationship between DAT density in STR and cortical-subcortical impairment in CBF. Based on the hypothesis that there is a correlation between DA availability and brain perfusion, we postulated that individuals with ADHD, with a higher DAT density in the basal ganglia, will have lower perfusion in the fronto-striatal-cerebellar networks. We used Tc-99m TRODAT-1 SPECT to measure DAT density and Tc-99m ECD SPECT to assess brain perfusion. Ten adolescents diagnosed with ADHD by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria were investigated. Analysis with Statistical Parametric Mapping 5 corrected for multiple comparisons, using small volume correction, showed a significant negative correlation between the DAT density in the STR and CBF in the cingulate gyrus, frontal lobe, temporal lobe, and cerebellum (pFDR <0.01). Our findings suggest that higher DAT density in the STR was associated with a decrease in the regional CBF in the cortical and subcortical attention network.
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Marco EM, Adriani W, Ruocco LA, Canese R, Sadile AG, Laviola G. Neurobehavioral adaptations to methylphenidate: The issue of early adolescent exposure. Neurosci Biobehav Rev 2011; 35:1722-39. [DOI: 10.1016/j.neubiorev.2011.02.011] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 02/21/2011] [Accepted: 02/22/2011] [Indexed: 01/14/2023]
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McBurnett K, Starr HL. OROS methylphenidate hydrochloride for adult patients with attention deficit/hyperactivity disorder. Expert Opin Pharmacother 2011; 12:315-24. [DOI: 10.1517/14656566.2011.546058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Positron emission tomography neuroimaging for a better understanding of the biology of ADHD. Neuropharmacology 2009; 57:601-7. [DOI: 10.1016/j.neuropharm.2009.08.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/29/2009] [Accepted: 08/04/2009] [Indexed: 11/20/2022]
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Effects of methylphenidate on working memory functioning in children with attention deficit/hyperactivity disorder. Eur J Paediatr Neurol 2009; 13:516-23. [PMID: 19056305 DOI: 10.1016/j.ejpn.2008.10.008] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 09/24/2008] [Accepted: 10/21/2008] [Indexed: 11/21/2022]
Abstract
BACKGROUND AND AIMS Children with attention deficit/hyperactivity disorder (ADHD) often show deficits in working memory performance. Methylphenidate (MPH) is an effective medication to improve these cognitive difficulties. This study aimed to clarify which effect MPH induces on the underlying functional networks of working memory. METHODS Fourteen boys diagnosed with ADHD and 12 healthy controls were investigated using functional magnetic resonance imaging (fMRI). Each patient was tested twice, once with medication and once without. The fMRI experiments consisted of three verbal N-back tasks with increasing difficulty. Functional images were acquired on a 3 Tesla head scanner. RESULTS On the behavioral level, medicated patients performed similar to healthy controls and significantly better than without medication. On the functional level, patients showed the expected frontal and parietal activations, which were more pronounced in the 2- and 3-back tasks. Healthy controls showed significantly more activation in these regions and additional activation in the cerebellum. Interestingly, patients showed an additional effect of laterality. Left-sided frontal and parietal activation in patients was significantly less pronounced than in controls. CONCLUSION Functional data indicate different activation patterns in verbal working memory tasks between healthy controls and patients with ADHD irrespective of medication condition. Intake of MPH led to a clear improvement on a behavioral level. However, this effect was not reflected by changes in functional brain organization. MPH-induced changes leading to better performance in verbal working memory tasks might be very subtle and therefore not detectable by fMRI.
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Cherkasova MV, Hechtman L. Neuroimaging in attention-deficit hyperactivity disorder: beyond the frontostriatal circuitry. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2009; 54:651-64. [PMID: 19835672 DOI: 10.1177/070674370905401002] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To review the findings of structural and functional neuroimaging studies in attention-deficit hyperactivity disorder (ADHD), with a focus on abnormalities reported in brain regions that lie outside the frontostriatal circuitry, which is currently believed to play a central role in the pathophysiology of ADHD. METHODS Relevant publications were found primarily by searching the MEDLINE and PubMed databases using the keywords ADHD and the abbreviations of magnetic resonance imaging (MRI), functional MRI, positron emission tomography, and single photon emission computed tomography. The reference lists of the articles found through the databases were then reviewed for the purpose of finding additional articles. RESULTS There is now substantial evidence of structural and functional alterations in regions outside the frontostriatal circuitry in ADHD, most notably in the cerebellum and the parietal lobes. CONCLUSIONS Although there is compelling evidence suggesting that frontostriatal dysfunction may be central to the pathophysiology of ADHD, the neuroimaging findings point to distributed neural substrates rather than a single one. More research is needed to elucidate the nature of contributions of nonfrontostriatal regions to the pathophysiology of ADHD.
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Abstract
INTRODUCTION Cerebral perfusion imaging using magnetic resonance imaging (MRI) is widely used in the research and clinical fields to assess the profound changes in blood flow related to ischemic events such as acute stroke, chronic steno-occlusive disease, vasospasm, and abnormal vessel formations from congenital conditions or tumoral neovascularity. With continuing improvements in the precision of MRI-based perfusion techniques, it is increasingly feasible to use this tool in the study of the subtle brain perfusion changes occurring in psychiatric illnesses. This article aims to review the existing literature on applications of perfusion MRI in psychiatric disorder and substance abuse research. The article also provides a brief introductory overview of dynamic susceptibility contrast MRI and arterial spin labeling techniques. An outlook of necessary steps to bring perfusion MRI into the realm of clinical psychiatry as a diagnostic tool is brought forth. Opportunities for research in unexplored disorders and with higher field strengths are briefly examined. METHODS PubMed, ISI Web of Knowledge & Scopus were used to search the literature and cross reference several neuropsychiatric disorders with a search term construct, including "magnetic resonance imaging," "dynamic susceptibility contrast," "arterial spin labeling," perfusion or "cerebral blood flow" or "cerebral blood volume" or "mean transit time." The list of disorders used in the search included schizophrenia, depression and bipolar disorder, dementia and Alzheimer's disease, Parkinson's disease, posttraumatic stress disorder, autism, Asperger disease, attention deficit, Tourette syndrome, obsessive-compulsive disorder, Huntington's disease, bulimia nervosa, anorexia nervosa, and substance abuse. For each disorder for which perfusion MRI studies were found, a brief overview of the disorder symptoms, treatment, prevalence, and existing models is provided, and previous findings from nuclear medicine-based perfusion imaging are overviewed. Findings of perfusion MRI studies are then summarized, and overlap of findings are discussed. Overarching conclusions are made, or an outlook for future work in the area is offered, where appropriate. RESULTS Despite the now fairly broad availability of perfusion MRI, only a limited number of studies were found using this technology. The search produced 13 studies of schizophrenia, 7 studies in major depression, 12 studies in Alzheimer's disease, and 2 studies in Parkinson's disease. Drug abuse and other disorders have mainly been studied with nuclear medicine-based perfusion imaging. The literature concerning the use of perfusion imaging in psychiatry has not been reviewed in the last 5 years or more. The use of MRI for perfusion measurements in psychiatry has not been reviewed in 10 years. CONCLUSIONS Although MRI-based perfusion imaging in psychiatry has mainly been used as a research tool, a path is progressively being cleared for its application in clinical diagnostic and treatment monitoring. The precision of perfusion MRI methods now rivals that of nuclear medicine-based perfusion imaging techniques. Because of their noninvasive nature, arterial spin labeling methods have gained popularity in studies of neuropsychiatric disorders such as schizophrenia, depression, Alzheimer's, and Parkinson's diseases. Perfusion imaging measurements have yet to be included within the diagnostic criteria of neuropsychiatric disorders despite having shown to have great discriminant power in specific disorders. As this young methodology continues to improve and research studies demonstrate the correlation of measured perfusion abnormalities to microcirculatory abnormalities and neuropsychiatric symptomatology, the idea of including such a test within diagnostic criteria for certain mental illnesses becomes increasingly plausible.
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Peculiar response to methylphenidate in adolescent compared to adult rats: a phMRI study. Psychopharmacology (Berl) 2009; 203:143-53. [PMID: 18998111 DOI: 10.1007/s00213-008-1379-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 10/13/2008] [Indexed: 02/02/2023]
Abstract
RATIONALE Adolescent rodents differ markedly from adults in several neuro-behavioural parameters. Moreover, 'paradoxical' responses to psychostimulants have been reported at this age. OBJECTIVES Thus, we investigated the responses of adolescent (post-natal day, PND, 34 to 43) and adult (PND >60) Sprague-Dawley male rats to the psychostimulant drug methylphenidate (MPH). We used pharmacological magnetic resonance imaging (phMRI) performed at 4.7 T under isoflurane anaesthesia. Following anatomical MRI, axial gradient echo images were collected continuously. After baseline recording (32 min), animals received MPH (0 or 4 mg/kg i.p.) and were recorded for further 32 min. RESULTS Region-specific changes in the blood-oxygenation level dependent (BOLD) signal were evident as a function of age. As expected, among adults MPH induced an increase of BOLD signal in nucleus accumbens (NAcc) and prefrontal cortex (PFC), with no effects in the hippocampus (Hip). Notably, among adolescents, MPH induced a marked and generalised decrease of BOLD signal, which occurred earlier in NAcc and PFC whilst being delayed in the Hip. Any bias in BOLD responses was excluded by the measurement of physiological parameters. CONCLUSIONS The present findings highlight the utility of phMRI in animal models. The peculiar negative BOLD effect found in adolescent rats may be suggestive of a reduced cerebro-vascular feedback and/or an increased MPH-induced neuronal activation. Data are relevant for a better understanding of brain/behavioural regulation during adolescent development. Moreover, a greater understanding of the differences between adult and adolescent drug responses will aid in the development of a more appropriate age-specific treatment strategy.
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Roy M, Dillo W, Bessling S, Emrich HM, Ohlmeier MD. Effective methylphenidate treatment of an adult Aspergers Syndrome and a comorbid ADHD: a clinical investigation with fMRI. J Atten Disord 2009; 12:381-5. [PMID: 19095892 DOI: 10.1177/1087054708320436] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Aspergers Syndrome can present as comorbid with attention-deficit/hyperactivity disorder (ADHD). Very few cases of the assessment and treatment of this comorbidity in adulthood are described in the research literature. METHOD A 26-year-old patient as suffering from ADHD in combination with Aspergers Syndrome is diagnosed. Treatment is started with methylphenidate (MPH), and the patient's clinical response is observed, psychological tests concerning attention are analyzed, and a functional magnetic resonance imaging (fMRI) examination is performed during an attention-task. RESULTS On the functional magnetic resonance imaging, a reduction of cerebral activity bilaterally in the parietal lobe under the influence of MPH is detected. CONCLUSION Besides the neurophysiological findings, this case reports the complex impairment caused by the combination of AD/HD with Aspergers Syndrome and the broad social and behavioral benefits of treatment with MPH for this comorbidity.
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Affiliation(s)
- Mandy Roy
- Hannover Medical School (MHH), Department of Psychiatry, Hannover, Germany.
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Methylphenidate has differential effects on blood oxygenation level-dependent signal related to cognitive subprocesses of reversal learning. J Neurosci 2008; 28:5976-82. [PMID: 18524902 DOI: 10.1523/jneurosci.1153-08.2008] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Complete understanding of the neural mechanisms by which stimulants such as methylphenidate ameliorate attention deficit hyperactivity disorder is lacking. Theories of catecholamine function predict that the neural effects of stimulant drugs will vary according to task requirements. We used event-related, pharmacological functional magnetic resonance imaging to investigate the effects of 60 mg of methylphenidate, alone and in combination with 400 mg of sulpiride, on blood oxygenation level-dependent (BOLD) signal in a group of 20 healthy participants during probabilistic reversal learning, in a placebo-controlled design. In a whole-brain analysis, methylphenidate attenuated BOLD signal in the ventral striatum during response switching after negative feedback but modulated activity in the prefrontal cortex when subjects maintained their current response set. The results show that the precise neural site of modulation by methylphenidate depends on the nature of the cognitive subprocess recruited.
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O'Gorman RL, Mehta MA, Asherson P, Zelaya FO, Brookes KJ, Toone BK, Alsop DC, Williams SCR. Increased cerebral perfusion in adult attention deficit hyperactivity disorder is normalised by stimulant treatment: a non-invasive MRI pilot study. Neuroimage 2008; 42:36-41. [PMID: 18511306 DOI: 10.1016/j.neuroimage.2008.04.169] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 03/28/2008] [Accepted: 04/11/2008] [Indexed: 11/17/2022] Open
Abstract
The neurobiological basis for attention deficit hyperactivity disorder (ADHD) has not yet been fully established, although there is a growing body of evidence pointing to functional and structural abnormalities involving the basal ganglia, cerebellum, and regions of frontal grey matter. The purpose of this study was to investigate regional cerebral perfusion in adults with ADHD and age-matched control subjects, and to assess the perfusion response to stimulant treatment in the ADHD group using a non-invasive magnetic resonance perfusion imaging technique. Whole-brain cerebral perfusion images were acquired from nine right-handed male patients with ADHD and eleven age-matched control subjects using a continuous arterial spin labelling (CASL) technique. The ADHD group was assessed once on their normal treatment and once after withdrawing from treatment for at least one week. An automated voxel-based analysis was used to identify regions where the cerebral perfusion differed significantly between the ADHD and control groups, and where the perfusion altered significantly with stimulant treatment. Regional cerebral perfusion was increased in the ADHD group in the left caudate nucleus, frontal and parietal regions. Psychomotor stimulant treatment acted to normalise perfusion in frontal cortex and the caudate nucleus with additional decreases in parietal and parahippocampal regions. These findings highlight the potential sensitivity of non-invasive perfusion MRI techniques like CASL in the evaluation of perfusion differences due to illness and medication treatment, and provide further evidence that persistence of ADHD symptomatology into adulthood is accompanied by abnormalities in frontal and striatal brain regions.
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Affiliation(s)
- Ruth L O'Gorman
- Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, London, UK. r.o'
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Cho SC, Hwang JW, Kim BN, Lee HY, Kim HW, Lee JS, Shin MS, Lee DS. The relationship between regional cerebral blood flow and response to methylphenidate in children with attention-deficit hyperactivity disorder: comparison between non-responders to methylphenidate and responders. J Psychiatr Res 2007; 41:459-65. [PMID: 16839567 DOI: 10.1016/j.jpsychires.2006.05.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 04/22/2006] [Accepted: 05/30/2006] [Indexed: 11/16/2022]
Abstract
In a sample of children with attention-deficit hyperactivity disorder (ADHD), a voxel based investigation of regional cerebral blood flow (rCBF) during resting state was conducted to identify functional differences between non-responders to methylphenidate (MPH) and responders. Thirty-four children with ADHD were examined by technetium-99m-hexamethylporphylenamine oxime (HMPAO) SPECT. According to clinical response after 8 weeks of treatment with MPH, they were classified as non-responders to MPH and responders. Using SPM analysis, we compared the SPECT images of non-responders to MPH with those of responders. Non-responders to MPH had higher rCBF in the left anterior cingulate cortex, the left claustrum, the right anterior cingulate cortex, and the right putamen relative to responders. In addition, lower rCBF was found in the right superior parietal lobule in non-responders to MPH relative to responders. Further stepwise discriminant analysis revealed that 88.2% could be correctly classified as either non-responders to MPH or responders when considering the extracted rCBF values in the left anterior cingulate cortex, the left claustrum, and the right superior parietal lobule. The current findings suggest that non-responders to MPH may have different patterns of rCBF in brain regions, which have been known as a part of frontal-striatal circuitry and posterior attentional system, respectively.
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Affiliation(s)
- Soo-Churl Cho
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Seoul National University College of Medicine, 28 Yungundong, Chongnogu, Seoul, Republic of Korea
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Pliszka SR. Pharmacologic Treatment of Attention-Deficit/Hyperactivity Disorder: Efficacy, Safety and Mechanisms of Action. Neuropsychol Rev 2007; 17:61-72. [PMID: 17242993 DOI: 10.1007/s11065-006-9017-3] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Studies examining the efficacy, safety and mechanisms of action of agents for the treatment of attention-deficit/hyperactivity disorder (ADHD) are reviewed, with an emphasis on newer agents such as the long acting stimulants and atomoxetine. Recent studies of medications are characterized by large, rigorously diagnosed samples of children, adolescents and adults with ADHD, use of standardized rating scales and extensive safety data. These studies confirm a robust treatment effect for the Food and Drug Administration approved agents ranging from 0.7 to 1.5. The most common short term side effects to the most commonly used agents include insomnia, loss of appetite, and headaches. Despite public controversy and labeling changes to warn of extremely rare cardiovascular and psychiatric side effects, the evidence does not support the hypothesis that medication for ADHD increases risk for sudden death, mania or psychosis. A wide variety of neuroimaging techniques including electrocephalogram (EEG) power, event related potentials (ERP), functional magnetic resonance imaging (fMRI), and positron emission tomography (PET) are beginning to examine the mechanisms of action of medications for ADHD, and implicating the catecholamines and prefrontal and anterior cingulate cortices as prime sites of actions for these agents.
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Affiliation(s)
- Steven R Pliszka
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, San Antonio, TX 78229-3900, USA.
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Effects of long-term methylphenidate treatment: a pilot follow-up clinical and SPECT study. Prog Neuropsychopharmacol Biol Psychiatry 2006; 30:1219-24. [PMID: 16616981 DOI: 10.1016/j.pnpbp.2006.02.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Although abnormalities in the regional cerebral blood flow (rCBF) responses to methylphenidate (MPH) treatment have been reported in children with attention deficit hyperactivity disorder (ADHD), there are few prospective longitudinal studies assessing the long-term effects of MPH and discontinuation effects after chronic treatment. METHODS The authors studied ten drug-naive children (2 girls, 8 boys, mean age+/-S.D.=9.60+/-1.96) diagnosed with ADHD by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) diagnostic criteria, using (99m)Tc-HMPAO-single photon emission computed tomography (SPECT). Patients were studied at baseline (visit 1), after 2 months of MPH treatment (visit 2) and after a drug-free period of 2 months following 12 months of MPH treatment (visit 3) at doses of 1 mg/kg/day. We evaluated SPECT data visually and semi-quantitatively. RESULTS Two months of chronic MPH treatment resulted in visually detectable improvement in hypoperfusion in the right frontal cortex and all areas of temporal cortex with the exception of left lateral temporal cortex. This improvement was still detectable on visual evaluations of SPECT data after 2 months of treatment discontinuation. The treatment effects that were detected visually were not statistically significant in semi-quantitative analyses. CONCLUSIONS Treatment effects of chronic MPH treatment may persist long after the discontinuation of the treatment.
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Kim YH, Ko MH, Na SY, Park SH, Kim KW. Effects of single-dose methylphenidate on cognitive performance in patients with traumatic brain injury: a double-blind placebo-controlled study. Clin Rehabil 2006; 20:24-30. [PMID: 16502746 DOI: 10.1191/0269215506cr927oa] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVES To determine the effect of a single dose of methylphenidate on the cognitive performance of patients with traumatic brain injury (TBI), and particularly on working memory and visuospatial attention. DESIGN A double-blind placebo-controlled study. The subjects were randomly divided into an experimental group taking methylphenidate and a control group taking a placebo. SETTING The Department of Rehabilitation Medicine of a university hospital. SUBJECTS Eighteen subjects with TBI (16 male and two female) were enrolled. INTERVENTIONS The patients were given 20 mg methylphenidate or a placebo. Cognitive assessments were performed at three times: before the medication as a baseline, 2 h after medication and at follow-up (48 h later). MAIN MEASURES Cognitive assessments consisted of working memory tasks and endogenous visuospatial attention tasks designed using SuperLabPro 2.0 software. Response accuracy and reaction time were measured. RESULTS There were significant improvements in response accuracy in the methylphenidate group compared with the placebo group for both the working memory and visuospatial attention tasks. A significant decrease in the reaction time was also observed in the methylphenidate group only for the working memory task. CONCLUSIONS The administration of single-dose methylphenidate has an effect in improving cognitive functioning following a TBI. The effects were most prominent regarding the reaction time of the working memory.
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Affiliation(s)
- Yun-Hee Kim
- Department of Physical Medicine and Rehabilitation, Stroke and Cerebrovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
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Szobot C, Roman T, Cunha R, Acton P, Hutz M, Rohde LA. Brain perfusion and dopaminergic genes in boys with attention-deficit/hyperactivity disorder. Am J Med Genet B Neuropsychiatr Genet 2005; 132B:53-8. [PMID: 15389753 DOI: 10.1002/ajmg.b.30096] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neuroimaging studies have suggested the involvement of several brain areas in attention-deficit/hyperactivity disorder (ADHD). Genetic investigations have supported the role of both dopamine D4 receptor gene (DRD4) and dopamine transporter gene (DAT1) in the vulnerability to the disorder. This study evaluates whether the presence of risk alleles at DRD4 and/or DAT1 genes is associated with differences in regional cerebral blood flow (rCBF) in a sample of ADHD boys. The rCBF was compared between ADHD patients with and without risk alleles at DRD4 (7-repeat allele) and/or at DAT1 (homozygosis for the 10-repeat allele) genes by single photon emission computed tomography (SPECT) during continuous performance test. Images were analyzed using statistical parametric mapping (SPM-99). No significant differences in rCBF were found both between ADHD boys with and without the 7-repeat allele at DRD4 locus, as well as between ADHD boys homozygous for the 10-repeat allele and ADHD subjects with other genotypes at the DAT1 locus. However, a significantly higher perfusion in the right middle temporal gyrus was found in the group with risk alleles at both DRD4 and DAT1 loci (n = 6) compared to ADHD boys without risk alleles at both loci (n = 28) (P < 0.05). Our findings suggest that a higher recruitment in middle temporal gyrus, an area associated to working memory and selective attention, should exist to compensate a putative effect of the interaction between these dopaminergic genes.
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Affiliation(s)
- Claudia Szobot
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Brazil
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Szobot CM, Ketzer C, Parente MA, Biederman J, Rohde LA. The acute effect of methylphenidate in Brazilian male children and adolescents with ADHD: a randomized clinical trial. J Atten Disord 2004; 8:37-43. [PMID: 15801333 DOI: 10.1177/108705470400800201] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To evaluate the acute efficacy of methylphenidate (MPH) in Brazilian male children and adolescents with ADHD. METHOD In a 4-day, double-blind, placebo-controlled, randomized, fix dose escalating, parallel-group trial, 36 ADHD children and adolescents were allocated to two groups: MPH (n = 19) and placebo (n = 17). Participants were evaluated pre- and posttreatment using the 10-item Conners Abbreviated Rating Scale (ABRS), the Children's Global Assessment Scale (CGAS), and a simplified version of the Continuous Performance Test (CPT). RESULTS The MPH group had a significantly greater decrease in ABRS scores and a significantly higher increase in CGAS scores than the placebo group (p < 0.01). The MPH group showed also a significantly higher proportion of patients with a robust improvement (decrement of at least 50% in the ABRS score after the intervention) than the placebo group (p < 0.01). The MPH effect size for the ABRS was 1.05 (95% CI = 0.73-1.37). CONCLUSION Our results extend the efficacy of MPH on the ADHD core symptoms extensively demonstrated in clinical trials with samples from some developed countries to a sample from a developing country where a diverse culture may modulate the clinical presentation of the disorder.
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Affiliation(s)
- C M Szobot
- Federal University of Rio Grande do Sul, Brazil
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Abstract
Attention deficit-hyperactivity disorder (ADHD) is a very common and heterogeneous childhood-onset psychiatric disorder, affecting between 3% and 5% of school age children worldwide. Although the neurobiology of ADHD is not completely understood, imbalances in both dopaminergic and noradrenergic systems have been implicated in the origin and persistence of core symptoms, which include inattention, hyperactivity, and impulsivity. The role of a genetic component in its etiology is strongly supported by genetic studies, and several investigations have suggested that the dopamine transporter gene (DAT1; SLC6A3 locus) may be a small-effect susceptibility gene for ADHD. Stimulant medication has a well-documented efficacy in reducing ADHD symptoms. Methylphenidate, the most prescribed stimulant, seems to act mainly by inhibiting the dopamine transporter protein and dopamine reuptake. In fact, its effect is probably related to an increase in extracellular levels of dopamine, especially in brain regions enriched in this protein (i.e. striatum). It is also important to note that dopamine transporter densities seem to be particularly elevated in the brain of ADHD patients, decreasing after treatment with methylphenidate. Altogether, these observations suggest that the dopamine transporter does play a major role in ADHD. Among the several polymorphisms already described in the SLC6A3 locus, a 40 bp variable number of tandem repeats (VNTR) polymorphism has been extensively investigated in association studies with ADHD. Although there are some negative results, the findings from these reports indicate the allele with ten copies of the 40 bp sequence (10-repeat allele) as the risk allele for ADHD. Some investigations have suggested that this polymorphism can be implicated in dopamine transporter gene expression in vitro and dopamine transporter density in vivo, even though it is located in a non-coding region of the SLC6A3 locus. Despite all these data, few studies have addressed the relationship between genetic markers (specifically the VNTR) at the SLC6A3 locus and response to methylphenidate in ADHD patients. A significant effect of the 40 bp VNTR on response to methylphenidate has been detected in most of these reports. However, the findings are inconsistent regarding both the allele (or genotype) involved and the direction of this influence (better or worse response). Thus, further investigations are required to determine if genetic variation due to the VNTR in the dopamine transporter gene is able to predict different levels of clinical response and palatability to methylphenidate in patients with ADHD, and how this information would be useful in clinical practice.
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Affiliation(s)
- Tatiana Roman
- Department of Morphological Sciences, Federal School of Medical Sciences of Porto Alegre, Porto Alegre, Brazil.
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