According to the National Institute for Mental Health, Schizophrenia strikes one percent of the population worldwide, including approximately 2.2 million people in the United States.
It is not the most common mental illness: The National Alliance on Mental Illness reports that bipolar disorder affects 1.2 percent of adult Americans; obsessive compulsive disorder affects 2 percent; and major depression affects 5 percent each year. Nonetheless, most of the people in psychiatric hospitals are in treatment for schizophrenia.
New and promising theories suggest potential causes of schizophrenia and ideas on how to treat it.
Researchers have asked such questions as, “Why do some people develop schizophrenia while others do not? What do people who develop schizophrenia have in common?” We know that schizophrenia occurs worldwide, and at approximately the same frequency, one percent of the population, everywhere it has been studied. There are no differences in the prevalence of schizophrenia by race, ethnicity, culture, or religion.
This suggests that these factors play little role in the development of the disease. Schizophrenia occurs at the same rate in males and females, though there are some sex differences in the expression of the disease. On average, males seem to be more severely disabled than females.
Are there any groups of people who are more likely than others to develop schizophrenia? In fact, the people most likely to develop schizophrenia are the relatives of schizophrenics.
This suggests that schizophrenia has a genetic cause. But genes are not the whole answer. We know that for two people with exactly the same genes - identical twins - if one is schizophrenic, the other has less than a 50 percent chance of also developing schizophrenia. Also, people who appear to have no schizophrenic relatives at all may still develop the disease. This tells us that the environment also plays a role in the development of schizophrenia.
In this section you will read about how to identify someone with schizophrenia, what symptoms make up the disease, and how clinicians diagnose patients. You will learn about the many factors that influence the development of schizophrenia. So far, we do not know the cause of schizophrenia, but we do know many things that increase a person’s likelihood of developing it. You will also read about various treatments for schizophrenia. A combination of medication, therapy, and community support has been shown to be the most effective treatment for the disease. Finally, you will read about how schizophrenia affects families and society.
Heather Barnett Veague, Ph.D.
Heather Barnett Veague attended the University of California, Los Angeles, and received her Ph.D. in psychology from Harvard University in 2004. She is the author of several journal articles investigating information processing and the self in borderline personality disorder. Currently, she is the Director of Clinical Research for the Laboratory of Adolescent Sciences at Vassar College. Dr. Veague lives in Stockbridge, Massachusetts, with her husband and children.