Schizophrenia is a neurological disorder characterized by specific behaviors, including psychotic episodes, delusions, paranoia, and loss of contact with reality.

What Is Schizophrenia?

Schizophrenia is a serious neurological disorder of unknown cause characterized by a specific type of disordered thinking and behavior. Typical symptoms of schizophrenia includes psychotic episodes, delusions * , paranoia * * component, but doctors think many other factors are involved. Schizophrenia is treated with antipsychotic * medications.

Positron emission tomography (PET) scans are computer-generated images of brain activity.

Positron emission tomography (PET) scans are computer-generated images of brain activity. When compared with PET scans of healthy people (left), the scans of people with schizophrenia (right) show disruptions in brain activity, changes in brain structures such as the ventricles, and decreased function in the frontal cortex. The red area in the brain on the right shows intense activity.
Science Source/Getty Images.

Schizophrenia is a brain disorder that affects a person's perceptions as well as thoughts and emotions. Family history of schizophrenia increases the chance of having the disorder, but the exact way it is inherited is unknown. Only some schizophrenic patients have detectable anatomical brain abnormalities. The cause of schizophrenia had not been determined as of 2016, yet drugs effective in its treatment had been identified. Schizophrenia is treated with antipsychotic drugs that primarily act on receptors in the brain for the neurotransmitters dopamine * and serotonin * . By inhibiting the activity of these receptors, antipsychotics are effective in decreasing some of the bizarre behavior typical of schizophrenia. Unfortunately, these medications often also have severe negative side effects, mostly affecting movement.

What Are Neurotransmitters?

Because areas of the brain need to interact with each other via these chemical signals, neuronal pathways that act as communication highways are formed during fetal development. Each neuronal pathway uses specific neurotransmitters to accomplish successful brain functioning. A disruption in the physical neuronal pathway, such as the loss of neuron cells or the loss of communication between neurons, may cause mental diseases such as schizophrenia. Additionally, an increase or decrease in the neurotransmitter chemical signals present in these pathways may also cause symptoms such as behavioral changes or neurological disorders and disease. Schizophrenia may be caused by both physical damage to certain groups of neurons in the brain and alteration of specific types of neurotransmitter signaling.

How Common Is Schizophrenia?

Schizophrenia is estimated to afflict 1 percent of the world's population. Approximately three million people have schizophrenia in the United States. First-degree relatives (such as siblings and parents) of a person with the disease have approximately a 10 percent chance of developing it. Fraternal twins (twins who do not have identical genes * ) have approximately a 10 to 12 percent chance. Children of two schizophrenic parents have about a 40 percent chance. However, the disease is not caused entirely by genetic factors. Because identical twins * have only a 30 to 50 percent risk of having the same schizophrenic illness, scientists know that other factors determine who develops the disease. Schizophrenia occurs equally in males and females. The disease may be seen at any age, but the most common age at onset is the late teens and early twenties for males and late twenties for females. Schizophrenia is associated with low economic status, probably due to a lack of proper maternal health care during fetal development.

What Causes Schizophrenia?

The cause of schizophrenia is unknown. Some patients have physical changes associated with the disease, including wasting of specific areas of the brain, enlargement of the ventricles * (normal spaces in the brain), and loss of neurons. Neurotransmitter signaling is often changed too, specifically regarding the neurotransmitter pathways for dopamine and serotonin. The imbalance in the activities of these pathways is complex: overactivity in some parts of the brain and decreased activity in other areas cause different symptoms.

What Are the Symptoms of Schizophrenia?

The symptoms of schizophrenia are divided into three types: positive, negative, and cognitive.

Positive symptoms * .

Negative symptoms

Negative symptoms mark the absence of normal social and interpersonal behaviors. There are various negative symptoms of schizophrenia. Schizophrenic patients are often less able to experience appropriate emotions or express their emotions. This reduced level of expression is known as blunted affect. Because they respond less and have less desire to interact, these patients often withdraw from others. Other negative symptoms may include a lack of motivation, energy, and ability to experience pleasure. Schizophrenic patients speak less and avoid speaking to others.

Cognitive symptoms

Schizophrenic patients may have confused thinking and speech, which makes it difficult for them to communicate effectively with others. Fractured (broken or fragmented) thoughts and communication are considered types of disorganized cognitive symptoms. Individuals with schizophrenia often seem to lose their train of thought and combine unrelated topics in a way that prevents a coherent conversation. Disorganized behaviors that include unnecessary repetitive movements are also common. Schizophrenics often seem restless or hyperactive. They may have difficulty paying attention or maintaining an organized lifestyle.

How Is Schizophrenia Diagnosed?

Schizophrenics often first display what are known as prodromal signs, or signs preceding a psychotic episode. Schizophrenic prodromal signs may include social isolation, odd behavior, lack of personal hygiene, and blunted emotions. The prodromal phase is followed by one or more separate psychotic episodes. Physicians examining the patient's behavior patterns first attempt to rule out disorders of mood that respond to antidepressants, such as bipolar disorder * . Sometimes schizophrenia is diagnosed through the patient's response to different therapeutic regimens. Schizophrenic symptoms are not affected by antidepressant medications * , but they are relieved by antipsychotic drugs.

Once other disorders have been excluded, the criteria for a diagnosis of schizophrenia are that a patient be continuously ill for at least six months and that there be one psychotic phase followed by one phase of odd behavior. During the psychotic phase, one or more of three groups of psychotic symptoms must be present. The three groups are delusions, hallucinations, and a disordered or incoherent thought pattern.

Do All Schizophrenia Patients Need Lifelong Antipsychotic Treatment?

While the prevailing assumption in the medical treatment of schizophrenics has been that patients need a lifetime of supervised medication, a 20-year longitudinal research study * (Harrow, Jobe and Faull) found that after four years of treatment, 30 to 40 percent of the patients in the study were no longer on medications. They did not relapse more frequently than those on long-term medications, were found to be significantly less psychotic, and had more periods of recovery. The study concluded that not all schizophrenic patients require a lifetime of antipsychotic medications.

How Is Schizophrenia Treated?

Schizophrenic patients are diagnosed and treated by psychiatrists * . A licensed therapist may perform rehabilitation therapy to help a schizophrenic patient function during times when the person is not in a psychotic episode. Treatment teams from supportive agencies may help with everyday living. Schizophrenia is treated with antipsychotic drugs used at the lowest effective doses. The antipsychotic drugs work mainly to antagonize (inhibit) dopamine and serotonin receptors in specific areas of the brain that are dysfunctional. Earlier antipsychotic medicines functioned primarily on dopamine receptors and had more side effects than later medications that also work on serotonin receptors. The older medications sometimes caused serious side effects such as severe, involuntary, repetitive movements of the face, arms, and legs. The newer medications do not have such troubling side effects. Positive symptoms of schizophrenia respond better to antipsychotic medications than the negative symptoms.

Although antipsychotic drug treatment is necessary for schizophrenic patients, it is not enough. Patients also require supportive psychotherapy * . Various psychosocial treatments are available for varying stages in the disease, and each patient requires a unique treatment regimen. Doctor and therapist appointments for medication management and psychological support are necessary in all stages of recovery, even when symptoms are under control. Peer support groups are also important. Assertive community treatment (ACT) programs are available for more severely affected patients. These programs may provide intensive services within a patient's home on a day-to-day basis. ACT teams can follow patients through all courses of their illness and assist them in normal living activities. Patients who are in the later stages of recovery and have few lingering symptoms may enter programs designed to help them achieve personal goals pertaining to work, education, and social interactions.

What Is the Prognosis for Schizophrenia?

The prognosis for schizophrenia varies according to each case. A diagnosis of schizophrenia does not necessarily mean that a person will experience a lifelong illness. Over a period of 25 to 30 years, approximately one-third of schizophrenic patients experience remission or even partial recovery. Some individuals lose their severe symptoms or learn to live acceptably with some minor symptoms. However, schizophrenia can be a severe and even dangerous disorder. A wide range of outcomes has been reported, including episodes of violence or severe incapacity. Suicide, accidents, and disease are common among patients with schizophrenia, along with an approximate 10-year decrease in life span. Typically, individuals have episodes of psychosis and episodes of remission * . Outcome is dependent on how effectively the medicine keeps the patient in periods of remission and how well the patient is able to deal with the symptoms still associated with these periods.

What Special Concerns Exist for Schizophrenia?

One concern for schizophrenic patients is that they may not cooperate with the treatment medical professionals think they need. Some patients may not remain in close contact with their treatment team, may not take all their medications consistently, and may not keep all their appointments. Schizophrenic patients are notorious for not being compliant with their necessary medications. This attitude develops either because they feel they have improved and no longer need medication, or because they want to avoid the side effects it causes. Unfortunately, without proper and consistent drug intervention, psychotic episodes are highly likely to recur.

See also Anxiety and Anxiety Disorders: Overview • Bipolar Disorder • Delusion, Delusional Disorders, and Paranoia • Depressive Disorders: Overview • Psychopharmacology • Psychosis


Books and Articles

Eck, Allison. “What Schizophrenia Can Teach Us About Ourselves.” Nova Next, October 22, 2014. Available at: (accessed July 6, 2016).

Harrow, M, T.H. Jobe and R.N Faull. “Do All Schizophrenia Patients Need Antipsychotic Treatment Continuously Throughout Their Lifetime? A 20-year Longitudinal Study.” Psychological Medicine 42, no. 10: 2145-55 (October 2012) Available at: (accessed July 6, 2016).

Torrey, E. Fuller. Surviving Schizophrenia: A Manual for Families, Patients, and Providers, 6th ed. New York: Harper Perennial, 2013.


National Institute of Mental Health. “Schizophrenia?” (accessed July 6, 2016).


IMAlive. Kristin Brooks Hope Center, 1250 Twenty-fourth Street NW, Suite 300, Washington, DC 20037. Toll-free: 800-784-2433. Website: (accessed July 6, 2016).

Mental Health America. 2000 N. Beauregard St., 6th Floor, Alexandria, VA 22311. Toll-free: 800-969-6642. Website: (accessed July 6, 2016).

National Alliance on Mental Illness. 3803 N. Fairfax Dr., Suite 100, Arlington, VA 22203. Toll-free: 800-950-6264. Website: (accessed July 6, 2016).

National Mental Health Consumers’ Self-Help Clearinghouse. 1211 Chestnut St., Suite 1207, Philadelphia, PA 19107. Toll-free: 800-553-4539. Website: (accessed July 6, 2016).

* delusions (de-LOO-zhuns) are false beliefs or judgments, that a person holds even in the face of proof that they are not true.

* paranoia (par-a-NOY-a) refers to either an unreasonable fear of harm by others (delusions of persecution) or an unrealistic sense of self-importance (delusions of grandeur).

* genetic (juh-NEH-tik) refers to heredity and the ways in which genes control the development and maintenance of organisms.

* antipsychotics are medications that counteract or reduce the symptoms of a severe mental disorder like schizophrenia.

* dopamine (DOE-puh-meen) is a neurotransmitter that is involved in the brain structures that control motor activity (movement).

* serotonin (ser-o-TO-nin) is a neurotransmitter, a substance that helps transmit information from one nerve cell to another.

* genes (JEENS) are the functional units of heredity that are composed of deoxyribonucleic acid (DNA) and help determine a person's body structure and physical characteristics. Inherited from a person's parents, genes are segments of chromosomes found in the nuclei of the body's cells.

* identical twins are twins produced when a single egg from the mother is fertilized and divides to form two separate embryos of the same sex with nearly identical DNA.

* ventricles are open cavities within the brain that contain the fluid which cushions and protects the central nervous system.

* insomnia is the abnormal inability to get adequate sleep.

* bipolar disorders are a group of mood disorders that are characterized by alternating episodes of depression and mania.

* antidepressant medications are used for the treatment and prevention of depression.

* psychiatrists (sy-KY-uh-trists) are medical doctors who have completed specialized training in the diagnosis and treatment of mental illness. Psychiatrists can diagnose mental illnesses, provide mental health counseling, and prescribe medications.

* psychotherapy (sy-ko-THER-apea) is the treatment of mental and behavioral disorders by support and insight to encourage healthy behavior patterns and personality growth.

* remission is an easing of a disease or its symptoms for a prolonged period.

* longitudinal research study is a research method in which data are gathered for the same subjects repeatedly over a period of time.

  This information is not a tool for self-diagnosis or a substitute for professional care.