Risk factors for psychosis in an ultra high-risk group: psychopathology and clinical features

The identification of individuals at high risk of developing a psychotic disorder has long been a goal of clinicians because it is thought that early treatment of this group may prevent onset of the disorder. However, little is known of predictive factors of psychosis, even within a high-risk group. This study followed up 104 young people thought to be at 'ultra high risk' for schizophrenia and other psychotic disorders by virtue of having a family history of psychotic disorder combined with some functional decline or the presence of subthreshold or self-limiting psychotic symptoms. All subjects were therefore symptomatic, but not psychotic, at intake. Thirty-six subjects (34.6%) developed frank psychotic symptoms within 12 months. Measures of symptom duration, functioning, disability and psychopathology were made at intake, 6 and 12 months. Poor functioning, long duration of symptoms, high levels of depression and reduced attention were all predictors of psychosis. A combination of family history of psychosis, a recent significant decrease in functioning and recent experience of subthreshold psychotic symptoms was also predictive of psychosis. Combining highly predictive variables yielded a method of psychosis prediction at 12 months with good positive predictive value (80.8%), negative predictive value (81.8%) and specificity (92.6%) and moderate sensitivity (60.0%). Within our symptomatic high-risk group, therefore, it appears possible to identify those individuals who are at particularly high risk of developing a psychotic disorder such as schizophrenia. Given the very high PPV and low false positive rate with this two-step process, it may be justifiable to target these individuals for intensive monitoring of mental state and even low-dose neuroleptic medication or other biological and psychosocial treatments depending on clinical condition. This indicated prevention approach could be further developed and preventive strategies in the psychoses refined. (C) 2003 Elsevier B.V. All rights reserved.