Harrington 1998.

Study characteristics
Methods	Allocation: randomisation using a series of opaque sealed envelopes which contained either a blank sheet or one bearing the letter F (for family therapy). Follow‐up period: 6 months. N lost to follow up: 13/162 (8%) for repetition data.
Participants	Inclusion criteria: i) 16 years of age or younger; ii) engaged in an episode of self‐poisoning; iii) living in a family. Exclusion criteria: i) engaged in self‐cutting or hanging; ii) in social service care; iii) current investigation of physical or sexual abuse; iv) diagnosed with a contraindicated psychiatric condition (e.g., psychosis); v) currently in inpatient treatment; vi) parent or child diagnosed with a learning disability; vii) parent or child seriously suicidal. Numbers: Of the 162 participants, 85 were allocated to the experimental arm and 77 to the control arm. Profile: 89.5 % (n = 145) were female, 64.5% (n = 104) were diagnosed with major depression, 10.5% (n = 17) were diagnosed with conduct disorder, 100% (n = 162) had a history of self‐poisoning. Source of participants: patients referred to mental health teams in one of four hospitals. Location: Manchester, UK.
Interventions	Experimental: manualised home based family therapy intervention involving one assessment session and 4 home visits in addition to treatment as usual. Control: treatment as usual. Therapist: 2 psychiatric social workers with a master’s degree. Type of therapy offered: family therapy. Length of treatment: not stated.
Outcomes	Included: i) repetition (data obtained from study authors); ii) suicide; iii) suicidal ideation; iv) compliance; v) hopelessness; vi) problem solving; vii) depression. Excluded: i) family functioning; ii) satisfaction with treatment; iii) cost‐effectiveness; iv) parent General Health Questionnaire.
Notes	Source of funding: "This research was supported by the Department of Health, London" (p.517). Declaration of author interests: no details on author interests were provided.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "a series of opaque and sealed envelopes containing either a blank sheet or the letter F were prepared and randomly assorted by an assistant" (p.2). Comment: Although it is likely the random sequence was adequately generated, without further information on the method used, this cannot be ascertained.
Allocation concealment (selection bias)	Low risk	Quote: "a series of opaque and sealed envelopes containing either a blank sheet or the letter F were prepared and randomly assorted by an assistant” (p.2). Comment: Use of opaque sealed envelope containing either a blank sheet or a sheet with the letter F printed on it would ensure that allocation was adequately concealed.
Blinding (performance bias and detection bias) Of participants	High risk	Comment: The nature of this study means that participants could have known to which group they had been allocated.
Blinding (performance bias and detection bias) Of personnel	High risk	Quote: “[The envelopes] were opened by the social worker at the time of the assessment, who then assigned the case to the family intervention plus routine care or routine care alone” (p.2) Comment: Personnel were not blinded.
Blinding (performance bias and detection bias) Of outcome assessors	Low risk	Quote: “Treatment assignment was entered on a register and concealed from the outcome assessors” (p.2)
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: “Outcome assessments were conducted with 154 (96%) of 162 cases at two months and 149 (92%) of 162 cases at six months” (p.3). “All the analyses were conducted ‘intent to treat’” (p.3).
Selective reporting (reporting bias)	Unclear risk	Comment: No reason to suspect that all outcomes were not measured, however, in the absence of the trial protocol, this cannot be ascertained.
Other bias	Low risk	Comment: No apparent other sources of bias.