NCT00409708.

Study characteristics
Methods	A 12‐week parallel trial with 2 arms: behavior therapy ER‐MPH and behavior therapy Phases: 1 or 2 (there is mention of a washout, but it appears to happen after the trial)
Participants	Number of participants screened: 142 Number of participants included: 109 randomised, baseline characteristics from 104 (66 boys, 38 girls) Number of participants followed‐up: 77 Number of withdrawals: 32 Diagnosis of ADHD: DSM‐IV (subtype not stated) Age: mean 8.4 years (SD 1.83, range 6‐12) IQ: not stated MPH‐naive: not stated Ethnicity: not stated Country: USA Setting: outpatient Comorbidity: some were exclusion criteria Comedication: not stated Additional sociodemographics: not stated Inclusion criteria Children of both genders, 6‐12 years old Written informed consent by the parent and the patient (over 7 years old) Diagnosis of ADHD Age‐appropriate cognitive functioning All patients who had at least one post‐baseline cytogenetic assessment in the core trial can enter the observation phase Exclusion criteria History of malignant neoplasm History of seizures (except childhood febrile seizures) Hyperthyroidism Concurrent medical condition which may interfere with trial
Interventions	Participants were randomly assigned to: receive either behavior therapy alone or with MPH. Number randomised to each group: 56 randomised to behavior therapy, 53 randomised to behavior therapy and MPH Mean medication dosage: not stated. Participants received between 10‐60 mg/d Administration schedule: not stated Duration of each medication: 12 weeks Washout before trial initiation: there is mention of a washout, but it appears to happen after the trial. Titration period: not stated Treatment compliance: not stated
Outcomes	ADHD symptoms Conners' ADHD/DSM‐IV Scale for Parents (CADS‐P) assessed at baseline to end of treatment (Week 12) Serious AEs Spontaneous reporting Non‐serious AEs Spontaneous reporting
Notes	Sample calculation: no Ethics approval: not stated Exclusion of MPH non‐responders/children who have previously experienced AEs while taking MPH: not stated Any withdrawals due to AEs: no Funding source: Novartis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not blinded
Incomplete outcome data (attrition bias) All outcomes	High risk	Almost a third of participants withdrew. Reasons for withdrawals are not stated. Selection bias (e.g. titration after randomisation → exclusion of MPH non‐responders or placebo responders): unclear
Selective reporting (reporting bias)	Low risk	Since no cytogenetic effects were observed, blood samples were not analysed for pharmacokinetics/pharmacodynamics, otherwise all outcomes reported