Staff training in positive behaviour support (PBS) is a widespread treatment approach for challenging behaviour in adults with intellectual disability.

To evaluate whether such training is clinically effective in reducing challenging behaviour during routine care (trial registration: NCT01680276).

We carried out a multicentre, cluster randomised controlled trial involving 23 community intellectual disability services in England, randomly allocated to manual-assisted staff training in PBS (n = 11) or treatment as usual (TAU, n = 12). Data were collected from 246 adult participants.

No treatment effects were found for the primary outcome (challenging behaviour over 12 months, adjusted mean difference = −2.14, 95% CI: −8.79, 4.51) or secondary outcomes.

Staff training in PBS, as applied in this study, did not reduce challenging behaviour. Further research should tackle implementation issues and endeavour to identify other interventions that can reduce challenging behaviour.

None.

Agitation in dementia is common, persistent and distressing and can lead to care breakdown. Medication is often ineffective and harmful.

To systematically review randomised controlled trial evidence regarding non-pharmacological interventions.

We reviewed 33 studies fitting predetermined criteria, assessed their validity and calculated standardised effect sizes (SES).

Person-centred care, communication skills training and adapted dementia care mapping decreased symptomatic and severe agitation in care homes immediately (SES range 0.3–1.8) and for up to 6 months afterwards (SES range 0.2–2.2). Activities and music therapy by protocol (SES range 0.5–0.6) decreased overall agitation and sensory intervention decreased clinically significant agitation immediately. Aromatherapy and light therapy did not demonstrate efficacy.

There are evidence-based strategies for care homes. Future interventions should focus on consistent and long-term implementation through staff training. Further research is needed for people living in their own homes.

Current health policy assumes better quality services lead to better outcomes.

To investigate the relationship between quality of mental health rehabilitation services in England, local deprivation, service user characteristics and clinical outcomes.

Standardised tools were used to assess the quality of mental health rehabilitation units and service users' autonomy, quality of life, experiences of care and ratings of the therapeutic milieu. Multiple level modelling investigated relationships between service quality, service user characteristics and outcomes.

A total of 52/60 (87%) National Health Service trusts participated, comprising 133 units and 739 service users. All aspects of service quality were positively associated with service users' autonomy, experiences of care and therapeutic milieu, but there was no association with quality of life.

Quality of care is linked to better clinical outcomes in people with complex and longer-term mental health problems. Thus, investing in quality is likely to show real clinical gains.