Schizophrenia, the most chronic and disabling of the severe mental disorders, is a major focus of research at the National Institute of Mental Health (NIMH), the world's foremost mental health scientific organization. This Federal agency takes the lead in neuroscientific investigation devoted to understanding the causes, diagnosis, prevention, and treatment of schizophrenia and other mental disorders, which afflict millions of Americans.

Since the Institute's inception 50 years ago, much has been learned about mental disorders and their effects on the brain. Revolutionary scientific advances in neuroscience, molecular biology, genetics, and brain imaging have provided some of the greatest insights into the complex organ that is the seat of thought, memory, and emotion. Thanks to these new tools, the scientific evidence that mental illnesses are brain disorders now exists.

More than 2 million Americans are affected by schizophrenia in any given year, and only one in five recovers completely. The illness, which may impair a person's ability to manage emotions, interact with others, and think clearly, typically develops in the late teens or early twenties. Symptoms include hallucinations, delusions, disordered thinking, and social withdrawal. Most people with schizophrenia continue to suffer chronically or episodically throughout their lives. Even between bouts of active illness, lost opportunities for careers and relationships, stigma, residual symptoms, and medication side effects often plague those with the illness. One of every 10 people with schizophrenia eventually commits suicide.

According to 1990 data, the most recent available, schizophrenia costs the nation $32.5 billion annually.

During the last decade, NIMH research has led to dramatic advances in the treatment of schizophrenia -- primarily in the development of several new medications with fewer side effects. However, some symptoms, such as social withdrawal and loss of motivation, are still insufficiently treated by the new drugs. Studies are continuing to determine how these and other promising medications interact with specific neurotransmitter systems in the brain and to ascertain which drugs work best for which people. In addition, a large-scale community study has shown that less than half of patients with schizophrenia receive appropriate treatment -- medication doses may have been incorrect and there was often inadequate use of psychosocial, vocational, and family therapies.

As the search for better treatments and ways to transfer those treatments to clinical practice continues, NIMH is harnessing the most sophisticated scientific tools available to determine the causes of schizophrenia. This brain disorder, like heart disease or diabetes, is complex and likely results from the interplay of genetic, behavioral, developmental, and other factors. There is an active search on several levels for the specific risk factors that may lead to schizophrenia.

Many years of family studies indicate that a vulnerability to schizophrenia is inherited. Still, scientists do not know how many genes are involved in this complex disorder, how the genetic predisposition is transmitted, or how behaviors or other events may interact with a genetic vulnerability to trigger the disorder. But an arsenal of new molecular tools and modern statistical analyses are allowing researchers to close in on particular genes that might make people more susceptible to schizophrenia by affecting, for example, brain development or neurotransmitter systems governing brain functioning.

On another research front, investigators supported by NIMH are using state-of-the-art imaging techniques to study the living brain. They have recently discovered specific, subtle abnormalities in the structure and function of the brains of patients with schizophrenia that may provide new insights into the origins of the disease. In other imaging studies, scientists have found evidence of early biochemical changes that may precede the onset of disease symptoms, prompting examination of the neural circuits that are most likely to be involved in producing those symptoms.

Research evidence from developmental neurobiologists suggests that schizophrenia may result when neurons form inappropriate connections during fetal development.

Although a defect may be present at birth, it may lie dormant until puberty, a time when significant nerve cell reorganization occurs in the brain. This research has spurred efforts to identify prenatal factors, including infections in utero, that may affect development.

Prepared by:
National Institute of Mental Health
Office of Communications and Public Liaison
6001 Executive Boulevard, Rm. 8184, MSC 9663
Bethesda, MD 20892-9663

NIH Publication No. 99-4500
Printed 1999

Updated: June 27, 2002