Early intervention in psychosis (EIP) has moved from the status of an interesting idea to being a novel, rather rare, service innovation, and onwards to firmly established Government policy in England in little over a decade. The pace and scale of this change demonstrates the power of good ideas that are significantly evidence-based and persuasively marketed: the adoption of EIP services in England would make a fascinating case study in applied social policy. Understandably, A Window of Opportunity does not dwell overlong on the ‘why’ of EIP, either in terms of the intellectual argument for early intervention or the reasons for its adoption within the Policy Implementation Guide (PIG) (Department of Health, 2001). Rather, it offers a well-written and attractively-produced guide to service managers and clinicians faced with the task of implementing policy, supplementing the abbreviated service description in the PIG with details drawn from the experience of some of those services in England that have already developed EIP services.

By drawing on existing practical experience the authors gently underline some deficiencies in the PIG. Four issues deserve particular mention. First, the Department of Health requires commissioners to develop services assuming an incidence rate of psychosis (15/100 000 per year) that is far too low for many catchment areas. Second, the PIG promotes a ‘one size fits all’ model of an EIP service as a free-standing entity covering a population in the region of 1 000 000 people, therefore relating to at least 25 community mental health teams. Third, the PIG mandates a separation between EIP services and existing child and adolescent mental health services. As the experience in Croydon (p. 46) shows, this is unnecessary and probably undesirable. Finally, there is no statement in the PIG about how to achieve a reduction in duration of untreated psychosis, and hence no funding by commissioners to achieve what is now a target for local mental health services.

Although far from definitive, A Window of Opportunity will be read with profit by commissioners, service managers and clinicians alike. It rightly encourages emerging EIP services to contact established ones so that the neophytes can learn from the successes (and occasional failures) of their predecessors, and provides a useful if not comprehensive reading list.