Biederman 2007a.

Methods	Multi‐center, randomized, double‐blind, placebo‐controlled, cross‐over trial Country: United States Number of study sites: 4 Statistical methods: modified ITT (all randomized children/adolescents who had at least one post‐randomization score on primary outcome measure)
Participants	Sample size: 52 children/adolescents with an ADHD diagnosis according to the DSM‐IV‐TR criteria Dropouts: 2 Psychiatric comorbid conditions: NR Age range: 6 years to 12 years Mean age (SD): 9.1 (1.7) years Sex: 33 (64%) males ADHD subtypes: 52 (100%) combined
Interventions	Three interventions (all 52 children/adolescents participated in each of the three interventions): Mixed amphetamine salts (long acting), either 10 mg/day, 20 mg/day or 30 mg/day (determined by dose optimisation period), (n = 52)* Lisdexamphetamine (long acting), either 30 mg/day, 50 mg/day or 70 mg/day (determined by dose optimisation period), (n = 52) Placebo (n = 52) Duration: 21 days (3 x 7‐day treatment periods)
Outcomes	Relevant outcomes: ADHD core symptom severity, assessed with the attention subscale (investigator) of the Swanson, Kotkin, Agler, M‐Flynn and Pelham scale Academic performance, assessed with Permanent Product Measure of Performance scale Clinical impression, assessed with Clinical Global Impressions ‐ Severity and Clinical Global Impressions ‐ Improvement scales Retention: number of participants who completed the study Adverse events Other outcomes: Conduct problems, assessed with deportment subscale of the Swanson, Kotkin, Agler, M‐Flynn and Pelham (SKAMP) scale Vital signs (blood pressure, pulse)
Notes	ClinicalTrials.gov identifier: NCT00557011 Authors' affiliation: university and pharmaceutical industry Study funding: pharmaceutical industry *Mixed amphetamine salts ‐ extended release was randomly chosen to represent the amphetamine group in this study for binary outcomes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of sequence generation not described
Allocation concealment (selection bias)	Low risk	Method of allocation concealment involved pre‐packaged, serially‐numbered drug kits, in which the next participant enrolled received the next available drug kit. Drug kits prepared by a third party
Incomplete outcome data (attrition bias) All outcomes	Low risk	Although the primary analysis only included trial completers, attrition was low at 4%
Selective reporting (reporting bias)	Low risk	Data provided on all outcomes listed in the registered protocol. Study appears to be free of selective reporting
Other bias	Low risk	Study appears to be free of other biases
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding of participants and personnel not described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Blinding of outcome assessment not described