In addition, they must also have problems at work or home for at least six months before this diagnosis can be made. Other possible problems have to be excluded to diagnose schizophrenia. Positive signs are present in a schizophrenic but not in an average person. These include hallucinations and delusions. Negative signs include the inability to express emotion and the inability to set goals and meet them.
Schizophrenia usually starts in the late teens or in the mid-thirties.
A few people have been diagnosed in childhood and some after age 40. Several million people in the United States are affected. It occurs slightly more often in men than in women. Schizophrenia typically runs in families, but can occur in a family with no history of it. There are several different types of schizophrenia.