A few disorders have some of the same symptoms as schizophrenia (schizophrenia spectrum disorders), including:
Schizotypal personality disorder. A person with schizotypal personality disorder has a difficult time developing close relationships with other people and may hold beliefs not shared by other people in his or her same culture. The person may also have unusual behaviors and learning difficulties.
Schizoid personality disorder. A person with schizoid personality disorder is aloof from other people and does not show many emotions.
Delusional disorder. People with delusional disorder believe things that could happen but are unlikely to happen. For example, a person with delusional disorder may believe he or she has cancer despite several negative test results. The person has no other psychotic symptoms, except those related to the delusion. But he or she is able to function in daily life.
Schizoaffective disorder. People with schizoaffective disorder have the same symptoms as people with schizophrenia. But they also have episodes of depression and times when they feel extremely happy or have lots of energy (mania). For more information, see the topics Depression and Bipolar Disorder.
Schizophreniform disorder. People with schizophreniform disorder have the same symptoms as people with schizophrenia. But their illness episodes do not last as long (from 1 to 6 months), and they may not have as many problems getting along with other people.
Medical Review:Kathleen Romito MD - Family Medicine & Christine R. Maldonado PhD - Behavioral Health