Table 2.

Assessment of Study Quality

Study Ref	Unbiased Selection of the Cohort	Selection Minimizes Baseline Differences in Prognostic Factors?	Sample Size Calculated?	Adequate Description of the Cohort?	Validated Method for Ascertaining Psychotic Symptoms	Validated Method for Ascertaining Loneliness	Adequate Handling of Missing Data
Angell et al, 2002	Partial	Yes	No/not reported	Yes	Yes	No	Yes
Badcock et al, 2015	Yes	Partial	n/a	Yes	Yes	No	Yes
Gayer-Anderson et al, 2014 (conference abstract)	Not reported	Not reported	No/not reported	Not reported	Not reported	Not reported	Not reported
Giblin et al, 2004	Partial	Partial	No/not reported	Partial	Yes	Yes	Not reported
Lindner et al, 2014	Unclear	Not reported	No/not reported	Partial	Yes	Yes	Not reported
Ludwig et al, 2013 unpublished	Partial	Yes	No/not reported	Partial	yes	Yes	Not reported
Meltzer et al, 2013	Yes	Yes	n/a	Yes	Partial	No	No
Roe et al, 2011	Partial	n/a (no control group)	No/not reported	Yes	Yes	Yes	Yes
Sundermann et al, 2014	Partial	n/a (no control group)	Yes	Yes	yes	No	Yes
Stein et al, 2013	Partial	No	No/not reported	Yes	Partial	Yes	Not reported
Switaj et al, 2014	Partial	n/a (no control group)	No/not reported	Partial	Yes	Yes	Not reported
Switaj et al, 2016—in press	Not reported	Yes	No/not reported	Not reported	Yes	Yes	Not reported
Tietjen, 1993	Partial	No	No/not reported	Yes	Yes	Yes	Not reported