Abstract

Psychotic disorders are a leading cause of disability-adjusted life years (DALYs); and although schizophrenia occurs infrequently in childhood and early adolescence, it is the ninth main cause of DALYs in boys between the ages of 10 and 14 years, and second main cause of DALYs in both genders between the ages of 15 and 19 years. A prodromal phase, which can last several years on average, precedes a majority of first-episode psychoses; it frequently leads to some decline in psychosocial functioning already but also offers an opportunity for an early detection of psychosis, and thus, for its indicated prevention. To this, two clinical high risk approaches, which had been developed in adult samples, are currently mainly followed, the ultra-high risk (UHR) criteria and basic symptom criteria. The UHR criteria were explicitly developed to predict a first-episode psychosis within 12 months, and indeed, the majority of conversions in clinical UHR cohorts do seem to occur within the first 12 months past initial assessment. The main UHR criterion, i.e. the attenuated psychotic symptoms (APS), includes symptoms that resemble positive symptoms of psychosis like delusions, hallucinations, and formal thought disorders with the exception that some insight into the abnormal nature of these experiences is still maintained. In contrast, the basic symptom criteria aim to detect the increased risk of psychoses at the earliest possible time using first subtle disturbances in information processing, which are experienced with full insight. Ideally, these changes should be detected when the person’s coping abilities have not yet been compromised and when the initial symptoms of an emerging disorder have not yet resulted in any functional decline. First results of prospective and community studies indicate that a combination of both approaches might be most favorable to increase sensitivity and a timely risk detection, in addition to establishing a change-sensitive risk stratification approach. However, as earlier indicated by reports of increased rates of hallucinatory experiences in children of the community, developmental aspects might play an important role, recent studies suggest both UHR and basic symptom criteria might be less predictive of psychosis and less clinically relevant in children and adolescents. Thus, an early detection of psychosis in children and adolescent seems to require special efforts.