Participant demographics
| All participants (n=186) | |
| Age of children and young people (<18 years) at the hospital in years, mean (SD) | 9 (4) |
| Age of parents, mean (SD) | 39 (8) |
| IMD decile, median (IQR) | 5 (3–9) |
| Gender, % (n) | |
| Female | 62 (116/186) |
| Male | 38 (70/186) |
| Primary recipient of the intervention, % (n/n total) | |
| Patient | 75 (139/186) |
| Parent/carer | 19 (36/186) |
| Sibling | 10 (18/186) |
| Ethnicity, % (n/n total) | |
| White | 62 (116/186) |
| Asian | 11 (21/186) |
| Black | 10 (19/186) |
| Any mixed background | 7 (13/186) |
| Any other ethnicity | 4 (8/186) |
| Not stated/prefer not to say | 5 (9/186) |
| Parent relationship to child, % (n/n total) | |
| Mother | 90 (167/186) |
| Father | 10 (19/186) |
| Parent marital status, % (n/n total) | |
| Married | 60 (62/104) |
| Single | 16 (17/104) |
| Divorced/separated | 12 (12/104) |
| Living with partner | 9 (9/104) |
| Widowed | 1 (1/104) |
| Not stated/prefer not to say | 3 (3/104) |
| Parent employment status, % (n/n total) | |
| Employed (full time) | 30 (31/104) |
| Employed (part time) | 24 (25/104) |
| Other | 18 (19/104) |
| Out of work | 11 (11/104) |
| Self-employed | 8 (8/104) |
| Unable to work | 6 (6/104) |
| Retired | 1 (1/104) |
| Not stated/prefer not to say | 3 (3/104) |
| Parent disability, % (n/n total) | |
| Yes | 11 (11/104) |
| No | 89 (93/104) |
| Presenting problems, % (n/n total) | |
| Anxiety | 45 (84/186) |
| Challenging behaviour | 38 (70/186) |
| Low mood | 28 (52/186) |
| Other | 14 (26/186) |
| Known pre-existing neurodevelopmental diagnosis, % (n/n total) | |
| Autism Spectrum Disorder | 15 (27/186) |
| Intellectual disability | 21 (39/186) |
| None | 62 (115/186) |
| Not stated/prefer not to say | 4 (7/186) |
| Patient type, % (n/n total) | |
| Outpatient | 96 (100/104) |
| Inpatient | 4 (4/104) |
| Need for translator, % (n/n total) | |
| Yes | 4 (8/186) |
| No | 96 (178/186) |
| County of origin, % (n/n total) | |
| <50 miles of London | 81 (151/186) |
| >50 miles of London | 15 (27/186) |
| Not stated/prefer not to say | 4 (8/186) |
| History of mental health input, % (n/n total) | |
| Yes | 46 (86/186) |
| No | 53 (98/186) |
| Not stated/prefer not to say | 1 (2/186) |
| History of risk present, % (n/n total) | |
| Yes | 18 (34/186) |
| No | 81 (151/186) |
| Not stated/prefer not to say | 1 (1/186) |
| Primary intervention allocated to, % (n/n total) | |
| MATCH | 32 (59/186) |
| Referral | 45 (84/186) |
| Neurodevelopmental assessment | 3 (6/186) |
| Signposting to resources only | 19 (35/186) |
| Other | 1 (2/186) |
| Self-reported change in physical health (6 months post), % (n/n total) | |
| Improved | 10 (10/104) |
| No change | 40 (42/104) |
| Deteriorated | 6 (6/104) |
| Not stated | 44 (46/104) |
Core participant demographics along with the mean and SD, median and IQR, number (n) and percent (%) of cases (where relevant) for all data. IMD decile=Index of multiple deprivation decile. NB: where total sample size is 104, this means data was only collected in the second year of the trial (post-pilot phase).