Systematic review of the evidence for service models delivering early intervention in psychosis outside the stand-alone centre

Aim: Although early intervention in psychosis is an accepted policy internationally, the evidence base for this paradigm, originates mostly from the specialist model. In a real world setting, variations of this model are often implemented. The aim of this paper is to systematically evaluate the evidence for delivering early intervention outside the specialist stand-alone centre. Methods: A systematic search following the PRISMA guidelines was undertaken in Medline, PsycInfo, Embase and the Cochrane trials register. The search was limited to articles in English from 1990 to end of January 2016. Inclusion criteria for the review comprised comparative evaluations of services delivering early intervention in psychosis outside the specialist model. Exclusion criteria included prodromal services, descriptions of services without reference to a comparator and stand-alone specialist services evaluated in comparison to treatment as usual. Results: There were 637 unique citations. Twenty-eight papers were reviewed at second-stage screening. The majority were excluded as they compared specialist early intervention with treatment as usual, did not evaluate the first episode or had no comparator. Seven peer-reviewed publications and two conference papers fulfilled criteria evaluating models of delivering early intervention other than the specialist model. Conclusions: There is a spaucity of evidence evaluating models other than specialist models in early intervention. Published studies are heterogeneous in design and outcome. Although there have been two recent trials evaluating integrated early intervention in comparison with treatment as usual, it remains unclear whether reported improved outcomes of specialist centres apply to other models.