Walitza 2007.

Methods	A prospective study analysing genomic damage in children with ADHD (initial sample size 38 children) before and 1 (30 children), 3 (21 children), and 6 (8 children) months after initiation of methylphenidate therapy. In addition a group of 9 children receiving chronic methylphenidate treatment were investigated
Participants	Prospective group Number of participants screened: not stated Number of participants included: 38 Number of participants followed up: 1 month: 30, 3 months: 21, 6 months: 8 number of withdrawals: 1 month: 8, 3 months: 17, 6 months: 30 Diagnosis of ADHD: DSM‐IV‐TR (subtype: not stated) Age: mean: 10 years old (range: 4.9‐17.0) IQ: above 70 Sex: 29 males, 9 females Methylphenidate‐naïve: 100% Ethnicity: not stated Country: Germany Comorbidity: not stated Comedication: no Sociodemographics: not stated Chronic group Number of participants screened: not stated Number of participants included: 9 Diagnosis of ADHD: DSM‐IV‐TR (subtype: not stated) Age: mean 11.2 years old (range 7.1‐16.0) IQ: above 70 Sex: 9 males, 0 females Methylphenidate‐naïve: 0%. All treated previously 6 months to 2 years Ethnicity: not stated Country: Germany Comorbidity: yes, 4 patients received additional medicine, but diseases not specified Comedication: yes, 4 patients; 1 received valproic acid and 3 received risperidone Sociodemographics: not stated Both groups Inclusion criteria: ADHD according to DSM‐IV‐TR criteria For the prospective group: drug‐naïvety For the chronic methylphenidate group: methylphenidate use prior to study initiation Exclusion criteria: Current smoking Current infection or an infection 14 days before blood sampling Extreme food patterns (e.g. vegans) Other psychiatric diagnoses such as anorexia nervosa, schizophrenia, any pervasive developmental disorder Neurologic disorders such as epilepsy History of acquired brain damage Evidence of fetal alcohol syndrome, and/or reports of severe prenatal, perinatal, or postnatal complications other severe diseases
Interventions	Methylphenidate type: not stated Mean methylphenidate dosage: prospective group: 0.54 mg/kg/day (5‐40 mg/day) increasing to 0.74 mg/kg/day (15‐45 mg/day) by the end of the trial. Chronic methylphenidate users: 0.83 mg/kg/day Administration schedule: not stated Duration of intervention: 1‐6 months Treatment compliance: not stated
Outcomes	Non‐serious adverse events Vital signs ECG Micronucleus analysis (in peripheral lymphocytes): blood samples (7.5 mL each) were collected 1 day before, and 1, 3, and 6 months after methylphenidate treatment. The micronucleus scoring was carried out by a single scorer 6 times for each sample in blinded manner Clinical laboratory values: white and red blood cell count, electrolytes, transaminases measured The measure for genomic damage was the frequency of micronuclei, a subset of chromosomal aberrations, in peripheral lymphocytes, obtained from blood samples No abnormal parameters were observed except slightly reduced values of total iron, without signs of hypochromic microcytic anaemia, which occurred in some patients before and during the treatment, independent of micronucleus deviation
Notes	Sample calculation: not stated Ethics approval: approved by the ethics committee of the University of Würzburg (study no. 140/03) Funding/vested interests: partially funded by grants from the German Research Foundation (Deutsche Forschungsgemeinschaft; KFO 125/1‐1) and from the Interdisciplinary Center for Clinical Research (IZKF N‐5 (1)) and was performed independent of financial or other support by companies producing or selling methylphenidate Authors' affiliations: the authors declare they have no competing financial interest Key conclusions of the study authors: the concern regarding a potential increase in the risk of developing cancer later in life after long‐term methylphenidate treatment is not supported. The study did not find any alteration in the number of micronucleated cells after methylphenidate treatment at 3 follow‐up intervals (up to 6 months) Exclusion of methylphenidate non‐responders/children who have previously experienced adverse events on methylphenidate: 2 withdrew after 1 month of treatment due to lack of effect Supplemental information regarding information on whether any of the children had intellectual disability received through personal email correspondence with the authors in October 2013 (Stopper 2013 [pers comm]). Also asked for vital signs and ECG in August 2014 (Stopper 2014 [pers comm]). The author no longer has access to this