Background: Very few interventional studies have directly examined the impact of treatment approaches on Health-Related Quality of Life (HRQL) in people with dementia. This is of particular importance in therapies to address behavioural symptoms, where HRQL is often severely affected. Methods: Analysis within the WHELD cluster-randomised factorial study in 16 UK care homes examining the impact of person-centred care in combination with Antipsychotic Review, Social Interaction and Exercise interventions. This study analysed impact on HRQL through the DEMQOL-Proxy. Results: Data on HRQL were available for 187 participants. People receiving Antipsychotic Review showed a significant worsening in two DEMQOL-Proxy domains (negative emotion: p=0.0...