Schizophrenics are usually subdivided into diagnostic categories based on which of these symptoms is predominant, such as paranoid or catatonic.
Schizophrenia afflicts men and women about equally often. Men usually show the first symptoms during the teens or twenties, while the onset for women ordinarily comes about a decade later. Acute symptoms develop suddenly and are typically more responsive to treatment. The prognosis is reasonably good in spite of brief relapses. Symptoms that develop gradually and persist for a long time with poor prognosis are called chronic. Schizophrenia is a familial disorder, which means that the incidence of schizophrenia is higher among the relatives of schizophrenics than it is in the general population. The heritability for schizophrenia has been estimated at between .60 and .90. This means that 10-40% of the variability is due to environmental factors.
Criteria for defining psychological disorders depend on whether cultural norms are violated, whether behavior is maladaptive or harmful, and