A substantial body of prospective research has established that individuals who develop attenuated psychotic symptoms accompanied by dysfunction at school and similar problems at home are much more likely than individuals in the general population to develop schizophrenia or other psychotic disorders within 2 years (at a rate of 10%—30% compared with 0.02%). The research has been conducted at multiple sites in the United States and Europe, and the convergence on a set of criteria that can be diagnosed reliably by different observers and have the external validity of leading to a dire illness has been established (3—5).
Attenuated psychosis syndrome arose from attempts to identify individuals who, based on their current symptoms, would likely develop schizophrenia within the next several years. The current diagnostic scheme, which does not contain this prodromal prediction, nonetheless requires prodromal features—specifically, an acceleration in symptom manifestation. Patients and their families can be poor historians, particularly when a time course must be established. Many attenuated symptoms are quite stable and do not lead to more severe illness, as in individuals who have schizotypal personality disorder, who rarely become psychotic, or in the nearly 10% of normal individuals who believe in sorcery or aliens or hear voices. The criterion that the patient must retain reality testing is notoriously subjective and can be met by some individuals who already have schizophrenia. The 10% conversion rate to schizophrenia is provocative, but it occurs in research settings that inevitably attract ill individuals at rates disproportionate to the overall population. However, the clinical care provided may be protective in these settings. It is not clear that if these criteria were to be applied more widely, perhaps even by school guidance counselors dealing with problematic children, they would yield a group with this high a conversion rate.