Risk, Disorder and Diagnosis

Abstract

develop schizophrenia and is generally not longer than a few years, with an average duration of about one year [7]. Thus it has been seen as a legitimate target for detection and intervention, with the aim of prevention of onset, or at least amelioration or delay of onset [8]. This is the background to the ‘ prodromal intervention ’ fi eld. However, even apparent prodromal symptoms lack specifi city. Characteristic prodromal features include sleep disturbance, irritability, lowered mood, anxiety and decline in school or work performance [7,9]. This clinical picture could be the result of a number of conditions, such as major depression, substance abuse and physical illness, as well as a psychotic prodrome. Even attenuated or isolated psychotic symptoms may not necessarily progress to a frank psychotic disorder, as these are now known to be quite common in the general population [10 – 14]. There are two implications of this lack of specifi city. First, is the recognition that a prodrome cannot be diagnosed as such prospectively, and that the terms ‘ prodrome ’ and ‘ prodromal ’ should not be used to refer to this clinical picture or those apparently presenting with it. This is more than pure semantics. Adoption of the term ‘ prodromal ’ to refer to individuals implies that they are on the path to schizophrenia. It suggests that the ‘ process ’ has already begun. Instead, as McGorry [15] has pointed out, terminology such as ‘ at risk mental state ’ should be used, to highlight that a person presenting with apparent prodromal symptoms may be at increased risk of onset of psychotic disorder within a brief time frame (1 – 2 years), but that onset is not inevitable. The second implication is that there needs to be some narrowing of the defi nition of ‘ at risk ’ so that those so identifi ed truly have a high likelihood of onset of fi rst episode psychosis within a brief period of time. One strategy to achieve this aim has been the development of the ultra high risk (UHR) criteria. These have been described elsewhere [8,16,17]. Essentially, there are three groups identifi ed: (i) attenuated psychotic symptoms