Table 3.

Characteristics of included HOP RCTs

Study	Number of HOP sessions	Comparison condition	Study population (with psychiatric diagnoses, if available)	Setting	% female	Mean age (SD)	Race/ethnicity (if above 5%)	N (HOP, Control)	Assessments after baseline	% Dropout at first post-baseline assessment	Country
Conley et al. 2020 [49]	4 (3 + 1 booster session)	TAU	College students aged 18 or older with self-reported mental illness (diagnoses not specified)	Campuses of three US universities	82	21 (5)	69% White, 18% Asian American, 8% African American	118 (63, 55)	Post; 3-week follow-up (i.e. after the booster session for HOP participants)	8%	USA
Corrigan et al. 2015 [48]	3	TAU	Adults with self-reported mental illness (diagnoses not specified)	Multiple California communities	64	46 (13)	50% White, 27% African American, 21% Hispanic/Latino, 8% Asian, 6% Native American	205 (107, 98; data available from: 51, 75)	Post; 1-month follow-up	39% of randomized participants did not attend groups and/or not complete pre- and post-assessments	USA
Mulfinger et al. 2018 [21]	3	TAU	Adolescents (13–18 years) with mental illness (59% depressive disorder, 17% anxiety disorder)	Inpatient (87%), day clinic (7%) and outpatient (6%) in 3 Dept.s of Child and Adolescent Psychiatry	69	16 (1)	100% White	98 (49, 49)	Post; 3-week follow-up	14%	Germany
Rüsch et al. 2014 [47]	3	TAU	Adults with self-reported mental illness (60% depressive disorder, 20% bipolar dis., 27% schizophrenia)	Outpatient / Community (Zürich)	59	42 (11)	100% White	100 (50, 50)	Post; 3-week follow-up	13%	Switzerland
Sheehan et al. (subm. [46])	3	TAU	Adults with a history of at least 1 lifetime suicide attempt (diagnoses not specified)	Community (Chicago)	39	48 (14)	82% Non-White, 18% White, 11% Hispanic/Latino	38 (19, 19)	Post; 3-week follow-up	8%	USA

TAU treatment as usual, SD standard deviation, post at the end of the HOP program/after the third session, N number of randomized participants