Table 2.

Measures used across the studies of the Dep-GP IPD dataset meeting inclusion criteria for the present study

Measure	Details	Scores and Cut-offs for Remission
The CIS-R (Lewis et al., 1992)	Consists of 14 symptom subsections scored 0–4 covering core features of depression, depressive thoughts (scored 0–5), fatigue, concentration/forgetfulness, and sleep, generalised anxiety, worry, irritability, obsessions, compulsions, health anxiety, somatic concerns, phobic anxiety (split into agoraphobia, social phobia, and specific phobia), and panic. A final section measures general health, impairment and weight change.	The total score ranges from 0-57 with a cut-off of ⩾12 used to indicate likely common mental disorder, primary and secondary diagnoses using ICD-10 criteria are given as are binary indictors of diagnosis for all the disorders assessed. The duration of each type of problem is also assessed for the present episode (or subsyndromal episode) up to the point of completing the CIS-R. Duration items are measured in five categories: (1) less than two weeks; (2) between two weeks and six months; (3) between six months and one year; (4) between one and two years; and (5) more than two years.
Beck Depression Inventory 2nd Edition (BDI-II)(Beck, Steer and Brown, 1996)	Consists of 21 items to assess depressive symptoms, each item is scored –-3.	There is a maximum score obtainable of 63, and a cut-off of ⩾10 is used indicate significant symptoms of depression, scores of <10 are therefore used to indicate remission in those that were previously depressed/scored ⩾10.
Patient Health Questionnaire 9-item version (PHQ-9)(Kroenke, Spitzer and Williams, 2001)	This is a depression screening measure, with respondents asked to rate how often they have been bothered by each of the nine symptom items over the preceding two weeks. Each item is scored 0–3	There is a maximum score of 27 with a cut-off of ⩾10 is used to indicate ‘caseness’ for depression, a score of 9 or below for those that were previously depressed is therefore considered to indicate remission
General Health Questionnaire (12-item version) (GHQ-12) (Goldberg, 1992)	Consists of 12 items related to present and recent health over the ‘few weeks’ prior to completion. Each item is related to depression or generalised anxiety, they are scored 0-0-1-1 for the four response options.	A cut-off of ⩾2 is used to indicate the likely presence of common mental disorder, and so scores of <2 for those formally scoring above this would be considered to indicate remission
Social Support Scale - adapted by authors of RCTs (Kessler et al., 2009) included in this IPD by adding one item to the Health and Lifestyles Survey Social Support Measure (Cox et al., 1987).	An 8-item instrument (the first seven of which are from the Health and Lifestyles Survey) assessing the degree to which participants rated the social support of their friends and family in each of the following domains: (1) being accepted for who one is; (2) feeling cared about; (3) feeling loved; (4) feeling important to them; (5) being able to rely on them; (6) feeling well supported and encouraged by them; (7) being made to feel happy by them; and (8) feeling able to talk to them whenever one might like. Items are scored 1-3, with total scores ranging from 8 to 24; higher scores indicate higher levels of perceived social support. The authors of the Health and Lifestyles Survey suggested the maximum score for social support (which was 21 on that scale) indicated ‘no lack of social support’, scores between 18 and 20 indicated a ‘moderate lack of social support’, and scores of 17 or below indicated a ‘severe lack of social support’.	N/A

CIS-R was used in all studies n = 4864. BDI-II was used in six studies (COBALT, GENPOD, IPCRESS, MIR, PANDA and TREAD), n = 2858; PHQ-9 was used in five studies (CADET, COBALT, MIR, PANDA and REEACT) n = 2807; GHQ was used in ITAS only n = 796; and the Social Support Scale was used in six studies (COBALT, GENPOD, IPCRESS, MIR, PANDA and TREAD) n = 2858.