Genetic and physiological. Schizoid personality disorder may have increased preva-
lence in the relatives of individuals with schizophrenia or schizotypa l personality disorder.
Culture-Related Diagnostic Issues
Individuals from a variety of cultural bac kgrounds sometimes exhibit defensive behaviors
and interpersonal styles that may be erroneously labeled as “schizoid.” For example, those
who have moved from rural to metropolitan  environments may react with “emotional
freezing” that may last for several months and manifest as solitary activities, constricted
affect, and other deficits in communication. Immigrants from other countries are some-
times mistakenly perceived as cold, hostile, or indifferent.
Gender-Related Diagnostic Issues
Schizoid personality disorder is diagnosed slightly more often in males and may cause
more impairment in them.
Differential Diagnosis
Other mental disorders with psychotic symptoms. Schizoid persona lity disorder can
be distinguished from delusional disorder, sc hizophrenia, and a bipolar or depressive dis-
order with psychotic features because these d isorders are all characterized by a period of
persistent psychotic symptoms (e .g., delusions and hallucinations). To give an additional
diagnosis of schizoid personality disorder, the personality disorder must have been present
before the onset of psychotic symptoms an d must persist when the psychotic symptoms