A study of COS has been ongoing at the NIMH since 1990. The diagnosis is made using unmodified DSM-III-R/IV criteria and, in most cases, after a drug-free inpatient observation. Although rare, occurring ~1/500th as often as adult-onset schizophrenia (AOS), the COS cases (n = 102 to date) clinically resemble poor-outcome AOS cases, in that all phenomenological, family, and neurobiological studies in COS show similar findings as in AOS, suggesting continuity between these two forms of the illness (Gogtay and Rapoport, 2008).
