Gibbor 2020b.

Study characteristics
Methods	RCT
Participants	N = 33 (16F/17M) DSM‐V criteria for dementia Mean MMSE 21.7 (SD 3.5; range 14‐27) Age 81.9 (SD 10.3; range 56‐98) Care homes
Interventions	Individual CST (delivered by researchers) (N = 17) Treatment‐as‐usual (N = 16)
Outcomes	Cognition: SMMSE, ADAS‐Cog Well‐being and Quality of Life: QoL‐AD (self‐report), QoL‐AD (proxy), Positive Psychology Outcome Measure (PPOM), Engagement and Independence in Dementia Questionnaire (EID‐Q)
Notes	45 minutes, 2 times a week for 7 weeks
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomly allocated by an independent web‐based randomiser to receive either iCST or TAU within the care home, with a 1:1 ratio.
Allocation concealment (selection bias)	Low risk	Randomisation conducted independently
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Researchers conducting follow‐up assessments were blinded to group allocation. Some risk for proxy QoL‐AD
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The treatment of missing data was unclear, with some imputation, some items omitted and some participants excluded for some measures.
Selective reporting (reporting bias)	Low risk	All outcome measures mentioned in methods were reported.
Other bias ‐ training and supervision	Unclear risk	All sessions conducted by members of the research team, also described as 'professionals', but no specific mention of their training or supervision
Other bias ‐ treatment manual	Low risk	Adapted from CST (Spector 2006) and iCST manuals (Yates 2014)