Samuels 2006.

Study characteristics
Methods	Double‐blind, randomised, cross‐over trial with 2 interventions: MPH placebo Phases: 2
Participants	Number of participants screened: not stated Number of participants included: 6 Number of participants followed up: not stated Number of withdrawals: not stated Diagnosis of ADHD: DSM‐IV (subtype not stated) Age: mean (not stated) IQ: mean (not stated) MPH‐naive: not stated Ethnicity: white (100%) Country: USA Setting: outpatient clinic Comorbidity: not stated Comedication: not stated Other sociodemographics: none Inclusion criteria Children 5‐15 years of age Long‐term stable dose of stimulant medicine for treatment of ADHD Recruited from local private paediatrician and psychiatric offices Exclusion criteria Receiving concomitant medication that might increase BP Documented hypertension requiring antihypertensive therapy
Interventions	Participants were randomly assigned to 1 of 2 possible drug condition orders of MPH and placebo Mean MPH dosage: not stated Administration schedule: each child was kept on his or her previous regimen of treatment and a corresponding placebo Duration of each medication condition: 24 h Washout before trial initiation: 3‐day run‐in Titration period: children were kept on stable medication doses and schedules Treatment compliance: not stated
Outcomes	Non‐serious AEs 24‐h ambulatory BP monitoring was performed on and off medication No separate data were available for MPH
Notes	Sample calculation: no Ethics approval: not stated Key conclusion of trial authors This trial provides evidence of a possible negative cardiovascular effect of stimulant medications in children with ADHD. This potential cardiovascular risk should be balanced against the beneficial behavioural effects of this class of medication Exclusion of MPH non‐responders/children who have previously experienced AEs while taking MPH before randomisation: yes, all participants were already on a stable dose of MPH Any withdrawals due to AEs: unclear Funding source: not declared Email correspondence with trial authors: July 2014. Emailed trial authors to ask for additional information but have not received a reply
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described; "randomized in double‐blind fashion"
Allocation concealment (selection bias)	Unclear risk	"Randomized in double‐blind fashion"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Described as "double‐blind". All medications and placebo were identically packaged by the research pharmacy
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	High risk	Only participants who successfully underwent an ambulatory BP monitoring trial at the end of each phase were included in the primary analyses. The first trial included 17 participants, 13 of whom underwent the second trial. Of these, data from 11 participants (of whom 6 received MPH) were analysed. Unclear why the rest were not included. Selection bias (e.g. titration after randomisation → exclusion): unclear
Selective reporting (reporting bias)	Unclear risk	Protocol not found