Table 1

Trial assessments and key participant-related procedures

Data collection time point (→)	Pre-randomisation	Point of randomisation	Post randomisation
Key data capture (measures)/trial procedures (↓)	Baseline	Baseline	1–15 weeks		16 weeks*	32 weeks	52 weeks
Screening	●
Eligibility assessment	●	●
Consent to join trial and randomisation		●
Demographics		●
Revised clinical interview schedule		●
Beck Depression Inventory-II (primary outcome at 16 weeks)		●			●	●	●
Generalised Anxiety Disorder Assessment		●			●		●
Patient Health Questionnaire-9 (depression symptoms)	●	●			●		●
Work and Social Adjustment Scale		●			●		●
Self-rating of global change					●	●	●
Positive And Negative Affect (PANAS-SF)		●			●		●
Health-related quality of life (EQ-5D-5L and EQ-VAS)		●			●	●	●
Work Productivity and Activity Impairment Questionnaire: General Health		●			●	●	●
Health and social care resource use questions					●	●	●
Guided self-help sessions*
Case report form(s) - therapist records
Working Alliance Inventory (Short Revised)* (therapist and participant rated)			●	●
Goal attainment record*			●	●
Qualitative interviews with patients and therapists†
Carer substudy: Depression Anxiety Stress Scales and Warwick-Edinburgh Mental Well-Being Scale		◊			◊		◊

Key: ● data capture/outcome measures; completion methods may vary depending on participant preferences. ◊ completed by caregiver.
*Intervention arm only.
†Months 6–12 decline/withdrawal qualitative interviews, months 10–20 end of treatment GSH participant qualitative interviews, 16–24 months TAU participant qualitative Interviews.
EQ-5D-5L, EuroQol five-dimension health status questionnaire ; EQ-VAS, EuroQol Visual Analogue Scale; GSH, guided self-help; PANAS-SF, Positive And Negative Affect Schedule-Short Form; TAU, treatment as usual .