Gil 1997.

Study characteristics
Methods	RCT. 2 arms. Assessed at pretreatment, post‐treatment
Participants	End of treatment: n = 49 Start of treatment: n = 49 Sex: 23 F, 26 M Mean age = 11.9 years Source = university medical centre, sickle cell centre Diagnosis = sickle cell anaemia (SS), sickle cell disease (SC), sickle beta thalassaemia Mean years of pain = not given
Interventions	"Cognitive coping skills" "Standard care control"
Outcomes	Primary pain outcome: none Primary disability outcome: none Primary depression outcome: none Primary anxiety outcome: none Pain sensitivity (pressure stimulator) Coping strategy questionnaire Disease severity: acute and chronic complications in past 12 months
Notes	COI: not reported Funding: "This work was supported by Grant RO1 HL46953‐06, by Project VI.B.2 in the Duke University‐University of North Carolina Sickle Cell Center Grant in P60HL2839‐13, and by the University of North Carolina at Chapel Hill GCRC Grant RR00046."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Participants were then randomly assigned to one of two conditions." Comment: probably done, method not described
Allocation concealment (selection bias)	Unclear risk	No description found in text Comment: probably not done
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No description found in text Comment: probably not done
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts reported in study
Selective reporting (reporting bias)	High risk	Data not fully reported