Other psychotic disorders such as delusional disorder share some similarities with schizophrenia, although the following two disorders are closely related:
Schizoaffective disorder: This is characterized by persistent symptoms of psychosis resembling schizophrenia, with additional periodic symptoms of mood or affective disorders including depression, mania and psychosis. This disorder is frequently confused with bipolar disorder, even though psychotic symptoms are present.6
Schizophreniform disorder: Although symptoms of schizophrenia are present, this condition has a shorter duration of at least one month, but less than six months. While impaired social and occupational functioning may be present, unlike in schizophrenia, this is not required for diagnosis.