title: Absence of cytogenetic effects in children and adults with attention-deficit/hyperactivity disorder treated with methylphenidate.
abstract: Attention-deficit/hyperactivity disorder (ADHD) is the most common psychiatric condition with onset in childhood, and in more than 50% of cases it persists into adulthood as a chronic disorder. Over five million methylphenidate (MPH) prescriptions were issued in the USA in 2003, mostly for children. A previous report [R.A. El-Zein, S.Z. Abdel-Rahman, M.J. Hay, M.S. Lopez, M.L. Bondy, D.L. Morris and M.S. Legator Cytogenetic effects in children treated with methylphenidate, Cancer Lett. 230 (2005) 284-291.] described the induction of chromosome abnormalities by MPH in children treated for three months, contrary to most of the in vitro and in vivo studies reported since then. We present new relevant information concerning the cytogenetic effects of MPH in children and adults. We include a prospective sample of 12 children and 7 adults with a new diagnosis of ADHD and naive to MPH. We analyzed the cytogenetic effects on peripheral lymphocytes before and three months after starting MPH therapy. The cytogenetic analyses included a cytokinesis-block micronucleus (CBMN) assay, a sister chromatid exchange (SCE) analysis and the determination of chromosome aberrations (CA). Following the same strategy and analyzing the same cytogenetic endpoints that were investigated in the original report [R.A. El-Zein, S.Z. Abdel-Rahman, M.J. Hay, M.S. Lopez, M.L. Bondy, D.L. Morris and M.S. Legator Cytogenetic effects in children treated with methylphenidate, Cancer Lett. 230 (2005) 284-291.], we found no evidence of increased frequency of micronuclei, sister chromatid exchanges or chromosome aberrations induced by MPH in children and adult populations. MPH treatment of children and adults with ADHD resulted in no significant genomic damage (as suggested by the three endpoints studied), results that do not support a potential increased risk of cancer after exposure to MPH.
authors.affiliation: Genes and Disease Program, Center for Genomic Regulation (CRG), UPF, Barcelona, Catalonia, Spain.
authors.forename: Immaculada
authors.initials: I
authors.lastname: Ponsa
authors.forename: Josep Antoni
authors.initials: JA
authors.lastname: Ramos-Quiroga
authors.forename: Marta
authors.initials: M
authors.lastname: Ribasés
authors.forename: Rosa
authors.initials: R
authors.lastname: Bosch
authors.forename: Anna
authors.initials: A
authors.lastname: Bielsa
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Ordeig
authors.forename: Marta
authors.initials: M
authors.lastname: Morell
authors.forename: Rosa
authors.initials: R
authors.lastname: Miró
authors.forename: Rafael
authors.initials: R
authors.lastname: de Cid
authors.forename: Xavier
authors.initials: X
authors.lastname: Estivill
authors.forename: Miquel
authors.initials: M
authors.lastname: Casas
authors.forename: Mònica
authors.initials: M
authors.lastname: Bayés
authors.forename: Bru
authors.initials: B
authors.lastname: Cormand
authors.forename: Amaia
authors.initials: A
authors.lastname: Hervás
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy* / Q000235:genetics*; D000697:Central Nervous System Stimulants / Q000009:adverse effects*; D002648:Child; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D008297:Male; D008774:Methylphenidate / Q000009:adverse effects*; D015162:Micronucleus Tests; D008875:Middle Aged; D012854:Sister Chromatid Exchange
chemical_list: D000697:Central Nervous System Stimulants; D008774:Methylphenidate