Assertive community treatment across the Atlantic: comparison of model fidelity in the UK and USA.

Background: The significant reductions in hospital admission demonstrated in US assertive community treatment (ACT) studies have not been replicated in the UK. Explanations cite poor UK 'model fidelity' and/or better UK standard care. No international model-fidelity comparisons exist.

Aims: To compare high-fidelity US ACT teams with a UK team.

Method: The UK 700's ACT team (n=97) was compared with high-fidelity US ACT teams (n=73) by using two measures: a forerunner of the Dartmouth Assertive Community Treatment schedule (to assess adherence to ACT principles) and 2-year prospective activity data.

Results: The UK and US teams had similar high-fidelity scores. Although significant differences were found in the amount and type of activity, practice differences in areas central to ACT were not great.

Conclusions: The failure of UK ACT studies to demonstrate the outcome differences of early US studies cannot be attributed entirely to the lack of ACT fidelity.