Thomas Tsirakis, BA

Late Onset Schizophrenia (LOS) is a rare disorder with a prevalence rate of less than 1 percent within the general population. LOS applies to those individuals who develop schizophrenia after the age of 40. The existence of LOS as a disorder separate from schizophrenia has been wrought with controversy, due mostly to a lack of consensus between European and North American medical standards. The general lack of agreement between the world's medical communities, as well as the overlapping of clinical features between LOS and other psychiatric disorders, has often resulted in misdiagnosis and confusion. In North America, LOS was completely eliminated from the third revised edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IIIR) of the American Psychiatric Association after the release of DSM-IV in 1994, and is now classified utilizing the same criteria as schizophrenia. The European medical community, however, still considers it to be a separate, yet related entity, with its own distinct symptomatology, and continues to define it utilizing DSM-IIIR criteria.