98 Schizophrenia Spectrum and Other Psychotic Disorders
Another distinguishing feature of schizophren iform disorder is the lack of a criterion
requiring impaired social and occupational functioning. While such  impairments may po-
tentially be present, they are not necessary for a diagnosis of schizophreniform disorder. 
In addition to the five symptom domain areas identified in the diagnostic criteria, the
assessment of cognition, depression, and mani a symptom domains is vital for making crit-
ically important distinctions between the va rious schizophrenia spectrum and other psy-
chotic disorders.
Associated Features Supporting Diagnosis
As with schizophrenia, currently there are no laboratory or psychometric tests for schizo-
phreniform disorder. There are multiple brain regions where ne uroimaging, neuropa-
thological, and neurophy siological research has indicated abnormalities, but none are
diagnostic.
Prevalence
Incidence of schizophreniform disorder across sociocultural settings is likely similar to
that observed in schizophrenia. In the United States and other developed countries, the in-
cidence is low, possibly fivefold less than th at of schizophrenia. In developing countries,
the incidence may be higher, especially for th e specifier “with good prognostic features”;
in some of these settings schizophreniform disorder may be as common as schizophrenia. 
Development and Course
The development of schizophreniform disorder  is similar to that of schizophrenia. About
one-third of individuals with an initial di agnosis of schizophreniform disorder (provi-
sional) recover within the 6-mo nth period and schizophreniform disorder is their final di-
agnosis. The majority of the remaining two-th irds of individuals will eventually receive a
diagnosis of schizophrenia or  schizoaffective disorder. 
Risk and Prognostic Factors 
Genetic and physiological. Relatives of individuals with  schizophreniform disorder