Connections and consequences in complex systems: insights from a case study of the emergence and local impact of crisis resolution and home treatment services.

In this article the broad contours of a complexity perspective are outlined. Complexity ideas are then drawn on to frame an empirical examination of the connections running between different levels of organisation in health and social care, and to underpin investigation into the intended and unintended local system consequences of service development. Data are used from a study conducted in the UK's mental health field. Here, macro-level policy has led to the supplementing of longstanding community mental health teams by newer, more specialised, services. An example includes teams providing crisis resolution and home treatment (CRHT) care as an alternative to hospital admission. Using an embedded case study design, where 'the case' examined was a new CRHT team set in its surrounding organisational environment, ethnographic data (with interviews predominating) were generated in a single site in Wales over 18 months from the middle of 2007. In a large-scale context favourable to local decision-making, and against a background of a partial and disputed evidence base, the move to establish the new standalone service was contested. Whilst users valued the work of the team, and local practitioners recognised the quality of its contribution, powerful effects were also triggered across the locality's horizontal interfaces. Participants described parts of the interconnected system being closed to release resources, staff gravitating to new crisis services leaving holes elsewhere, and the most needy service users being cared for by the least experienced workers. Some community mental health team staff described unexpected increases in workload, and disputes over eligibility for crisis care with implications for system-wide working relations. Detailed data extracts are used to illustrate these connections and consequences. Concluding lessons are drawn on the use of evidence to inform policy, on the significance of local contexts and system interfaces, and on anticipating the unexpected at times of change.