Table 1.

Characteristics of included studies

Study	Location	No.	Diagnosis Φ	Age (yr)	Sex (F)	Race (BME)	Employment Ω
Mutual Support
Edmundson 1982 [51]	Florida USA	80	N/R	N/R	N/R	N/R	N/R
Kaplan 2011 [47]ψ	Pennsylvania USA	300	22% SS 78% mood	47	66%	13%	64%
Rogers 2007 [42]	Multiple sites USA	1827	50% SS 44% mood	43	60%	43%	29%
Segal 2011 [49]	California USA	162	41% SS 59% mood	37	54%	13%	4%
Peer Support
Barbic 2009 [39]	Ontario CA	33	79% SS 21% BPD	45	33%	N/R	12%
Chinman 2013 [36]	South Western USA	282α		53	11%	46%	N/R
Cook 2012 [46]	Tennessee, USA	428	21% SS 40% BPD 18% mood	43	56%	54%	9%
Cook 2011 [45]	Ohio USA	555	20% SS 26% BPD, 24% MDD	46	66%	37%	15%
Craig 2004 [38]	London UK	45	100% SS	38	33%	N/R	N/R
Davidson 2004 [41]	Connecticut USA	260	50% SS 34% mood	42	57%	18%	20%
Proudfoot 2012 [37]	New South Wales Australia	407	100% BPD	N/R	70%	N/R	N/R
Rivera 2007 [48]	New York USA	255	48% SS 26% BPD 22% MDD	38	49%	71%	N/R
Simon 2011 [27]	USA	118	100% BPD	N/R	72%	19%	N/R
Sledge 2011 [44]	Connecticut USA	89	69% SS 31% mood	41	49%	N/R	N/R
Van Gestel-Timmermans 2012 [50]	Netherlands	333	33% SS	44	66%	N/R	N/R
Peer Delivered Services
Sells 2006 [43]	Connecticut USA	137	61% SS 70% multiple	42	39%	11%	N/R
Clarke 2000 [40]	Oregon USA	178	60% SS31% SM	37	39%	18%	N/R
Solomon 1995 [28]	Pennsylvania USA	96	82% SS 12% mood	41	47%	37%	N/R

^ΦParticipants with a schizophrenia spectrum (SS) disorder, bipolar disorder (BPD), major depressive disorder (MDD), substance misuse (SM), or mood disorder.

^ΩCurrently employed.

ΨTwo intervention groups (a peer support email list and an online bulletin board) were merged for analysis.

αRandomised in six teams.