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 cannot be proven or continue to believe things that have been proven to be wrong or false. These false beliefs can be about their bodies, their self-worth, or other people.
• Schizoaffective disorder. People with schizoaffective disorder have the same symptoms as people with schizophrenia. However, 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. However, 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.