Background: Mental health care in the United Kingdom is rapidly changing, but many commentators, particularly sociologists and psychologists, view systems as remaining wedded to a medical model and not “fit for purpose”. If services are to improve, the way that mental health problems are understood by the services providing care needs to change radically.

Aims: To illustrate how a psychological model of mental disorder – the “mediating psychological processes model”– could assist mental health service policy development and implementation.

Method: A review of selected literature and policy documents was conducted.

Results: A “manifesto” for mental health service policy is presented, based on psychological principles.

Conclusions: Psychological models, at least in addition to medical approaches, could better inform policy and service design.