2. Suggested design for a new study.

Methods	Allocation: randomised Blinding: n/a. There is a very low likelihood of blinding being maintained in a such a complex intervention. Duration: > 2 years intervention period, at least > 1‐year follow‐up period
Participants	Diagnosis: psychosis and related diagnoses N = 477* Gender: men and women Age: 14 to 65
Interventions	Extended SEI comprised of continuation of SEI treatment combined with small caseload sizes (< 25), and inclusion of booster sessions of therapeutic intervention where indicated.
Outcomes	Global state: recovery** Global state: relapse Service use: disengagement from services Service use: admission to psychiatric hospital Functioning: clinically important change in functioning Quality of life: clinically important change in quality of life Economics: cost of care
Notes	* Sample size suggested relates to the size of a study with sufficient power to highlight a 10% difference between groups for the primary outcome ** Primary outcome

SEI: specialised early intervention