Blakemore 1993.

Methods	Parallel randomised controlled trial.
Participants	Participants: volunteers or professionally referred parents of children with ADHD. Sex: 24 mothers; 24 fathers. Age of participants: not stated. Unit of allocation: individual family. Number randomised: 24 families per year (8 group‐based intervention; 8 individual‐based intervention; 8 control). Number used in analysis: number available for analysis n=16 (8 intervention; 8 control)*. Country & setting: Canada; single‐site; recruited from community settings; intervention delivered in an outpatient clinic. Inclusion criteria: parents with at least one child aged 6 to 11 years with evidence of ADHD in a wide range of situations; ADHD evident before the age of six. Exclusion criteria: a serious neurological difficulties; Conduct Disorder in the child with ADHD; a serious marital difficulties. Ethnicity: not stated. Baseline characteristics: not stated.
Interventions	Three conditions: Cognitive‐behavioural parenting programme; Individual‐based parent programme; wait‐list control. Duration of intervention: 12 weeks; two additional sessions delivered at three and six months after the termination of initial 12 sessions. Length of follow‐up: none.
Outcomes	Stress (Parenting Stress Index)*.
Notes	*Insufficient data to calculate effect sizes. We requested clarification from the trial investigators but no further information was available at the time this review was prepared.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Information reported insufficient for a judgement to be made. We requested clarification from the trial investigators, but no further information was available at the time this review was prepared.
Allocation concealment (selection bias)	Unclear risk	Information reported insufficient for a judgement to be made. We requested clarification from the trial investigators, but no further information was available at the time this review was prepared.
Blinding (performance bias and detection bias) Participants	High risk	Review authors judged that it would not be possible to fully blind participants in this type of study, and found no indication of any specific additional measures taken to reduce the risk of bias that might result from differential behaviours by participants.
Blinding (performance bias and detection bias) Personnel	High risk	Review authors consider the design of study means personnel would be aware which groups had been assigned to two study conditions.
Blinding (performance bias and detection bias) Outcome assessors	Low risk	Investigators report that participants were "presented with a structured interview by a research assistant who is blind to the treatment status of the parent" (page 80). Review authors consider the outcome assessor was blinded and that the non‐blinding of others was unlikely to have introduced bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Investigators report that the data presented "were obtained during the first year of the project with 24 subjects (8 subjects in each of the three treatment conditions)" (page 81). There was no missing data.
Selective reporting (reporting bias)	Low risk	Review authors judge that the published report includes all expected outcomes, including those that were pre‐specified.
Other bias	Low risk	The study appeared to be free of other sources of bias.