Defining subjects at risk for psychosis: a comparison of two approaches.

The ability to detect individuals at high risk for developing schizophrenia before they express the disease will lead to targeted early intervention. It has been proposed that subjects at risk share a core deficit with people who already have schizophrenia. This includes cognitive impairment, affective symptoms, social isolation and decline in social functioning. In a sample of 104 help-seeking patients from a specialised outpatient clinic we investigated how well two different sets of criteria define the at-risk group and capture this core deficit. One set of criteria is the well-established ultra high-risk model of McGlashan et al. [McGlashan 2001 (SIPS) McGlashan, T. H., Miller, T. J., Woods, S. W., et al. (2001) Structured Interview for Prodromal Syndromes (Version 3.0, unpublished manuscript). New Haven, Connecticut: PRIME Research Clinic, Yale School of Medicine.]; the other criteria were those defined by Cornblatt et al. [Cornblatt, B., Lencz, T., Smith, C.W., Correll, C.U., Auther, A., Nakayama, E., 2003. The schizophrenia prodrome revisited: a neurodevelopmental perspective. Schizophr. Bull. 29, 633-651.]. There was considerable overlap in the two sets of criteria. However, when the basic symptoms of Klosterkötter [Klosterkötter, J., Hellmich, M., Steinmeyer, E.M., Schultze-Lutter, F., 2001a. Diagnosing schizophrenia in the initial prodromal phase. Arch. Gen. Psychiatry, 58, 158-164.] were included in the McGlashan et al. model, a more narrow and homogeneous group was defined.