Schizophrenia may have a variety of symptoms. Usually the illness develops slowly over months or years. Like other chronic illnesses, schizophrenia cycles between periods of fewer symptoms and periods of more symptoms.

At first, you may feel tense, or have trouble sleeping or concentrating. You can become isolated and withdrawn, and have trouble making or keeping friends.

As the illness continues, psychotic symptoms develop:

• Appearance or mood that shows no emotion (flat affect)
• Bizarre movements that show less of a reaction to the environment (catatonic behavior)
• False beliefs or thoughts that are not based in reality (delusions)
• Hearing, seeing, or feeling things that are not there (hallucinations)

Problems with thinking often occur:

• Problems paying attention
• Thoughts "jump" between unrelated topics (disordered thinking)

Symptoms can be different depending on the type of schizophrenia:

• Paranoid types often feel anxious, are more often angry or argumentative, and falsely believe that others are trying to harm them or their loved ones.
• Disorganized types have problems thinking and expressing their ideas clearly, often exhibit childlike behavior, and frequently show little emotion.
• Catatonic types may be in a constant state of unrest, or they may not move or be underactive. Their muscles and posture may be rigid. They may grimace or have other odd facial expressions, and they may be less responsive to others.
• Undifferentiated types may have symptoms of more than one other type of schizophrenia.
• Residual types experience some symptoms, but not as many as those who are in a full-blown episode of schizophrenia.

People with any type of schizophrenia may have difficulty keeping friends and working. They may also have problems with anxiety, depression, and suicidal thoughts or behaviors.

A psychiatrist should perform an evaluation to make the diagnosis. The diagnosis is made based on a thorough interview of the person and family members.

No medical tests for schizophrenia exist. The following factors may suggest a schizophrenia diagnosis, but do not confirm it:

• Course of illness and how long symptoms have lasted
• Changes from level of function before illness
• Developmental background
• Genetic and family history
• Response to medication

CT scans of the head and other imaging techniques may find some changes that occur with schizophrenia and may rule out other disorders.