Schizophrenia.

Ci-dessous un extrait traitant le sujet : Schizophrenia.. Ce document contient 2519 mots. Pour le télécharger en entier, envoyez-nous un de vos documents grâce à notre système d’échange gratuit de ressources numériques ou achetez-le pour la modique somme d’un euro symbolique. Cette aide totalement rédigée en format pdf sera utile aux lycéens ou étudiants ayant un devoir à réaliser ou une leçon à approfondir en : Echange

---

Schizophrenia.
I

INTRODUCTION

Schizophrenia, severe mental illness characterized by a variety of symptoms, including loss of contact with reality, bizarre behavior, disorganized thinking and speech,
decreased emotional expressiveness, and social withdrawal. Usually only some of these symptoms occur in any one person. The term schizophrenia comes from Greek
words meaning "split mind." However, contrary to common belief, schizophrenia does not refer to a person with a split personality or multiple personality. (For a
description of a mental illness in which a person has multiple personalities, see Dissociative Identity Disorder.) To observers, schizophrenia may seem like madness or
insanity.
Perhaps more than any other mental illness, schizophrenia has a debilitating effect on the lives of the people who suffer from it. A person with schizophrenia may have
difficulty telling the difference between real and unreal experiences, logical and illogical thoughts, or appropriate and inappropriate behavior. Schizophrenia seriously
impairs a person's ability to work, go to school, enjoy relationships with others, or take care of oneself. In addition, people with schizophrenia frequently require
hospitalization because they pose a danger to themselves. About 10 percent of people with schizophrenia commit suicide, and many others attempt suicide. Once
people develop schizophrenia, they usually suffer from the illness for the rest of their lives. Although there is no cure, treatment can help many people with
schizophrenia lead productive lives.
Schizophrenia also carries an enormous cost to society. People with schizophrenia occupy about one-third of all beds in psychiatric hospitals in the United States. In
addition, people with schizophrenia account for at least 10 percent of the homeless population in the United States (see Homelessness). The National Institute of Mental
Health has estimated that schizophrenia costs the United States tens of billions of dollars each year in direct treatment, social services, and lost productivity.

II

PREVALENCE

Approximately 1 percent of people develop schizophrenia at some time during their lives. Experts estimate that about 1.8 million people in the United States have
schizophrenia. The prevalence of schizophrenia is the same regardless of sex, race, and culture. Although women are just as likely as men to develop schizophrenia,
women tend to experience the illness less severely, with fewer hospitalizations and better social functioning in the community.

III

SYMPTOMS

Schizophrenia usually develops in late adolescence or early adulthood, between the ages of 15 and 30. Much less commonly, schizophrenia develops later in life. The
illness may begin abruptly, but it usually develops slowly over months or years. Mental health professionals diagnose schizophrenia based on an interview with the
patient in which they determine whether the person has experienced specific symptoms of the illness.
Symptoms and functioning in people with schizophrenia tend to vary over time, sometimes worsening and other times improving. For many patients the symptoms
gradually become less severe as they grow older. About 25 percent of people with schizophrenia become symptom-free later in their lives.
A variety of symptoms characterize schizophrenia. The most prominent include symptoms of psychosis--such as delusions and hallucinations--as well as bizarre
behavior, strange movements, and disorganized thinking and speech. Many people with schizophrenia do not recognize that their mental functioning is disturbed.

A

Delusions

Delusions are false beliefs that appear obviously untrue to other people. For example, a person with schizophrenia may believe that he is the king of England when he is
not. People with schizophrenia may have delusions that others, such as the police or the FBI, are plotting against them or spying on them. They may believe that aliens
are controlling their thoughts or that their own thoughts are being broadcast to the world so that other people can hear them.

B

Hallucinations

People with schizophrenia may also experience hallucinations (false sensory perceptions). People with hallucinations see, hear, smell, feel, or taste things that are not
really there. Auditory hallucinations, such as hearing voices when no one else is around, are especially common in schizophrenia. These hallucinations may include two or
more voices conversing with each other, voices that continually comment on the person's life, or voices that command the person to do something.

C

Bizarre Behavior

People with schizophrenia often behave bizarrely. They may talk to themselves, walk backward, laugh suddenly without explanation, make funny faces, or masturbate in
public. In rare cases, they maintain a rigid, bizarre pose for hours on end. Alternately, they may engage in constant random or repetitive movements.

D

Disorganized Thinking and Speech

People with schizophrenia sometimes talk in incoherent or nonsensical ways, which suggests confused or disorganized thinking. In conversation they may jump from
topic to topic or string together loosely associated phrases. They may combine words and phrases in meaningless ways or make up new words. In addition, they may
show poverty of speech, in which they talk less and more slowly than other people, fail to answer questions or reply only briefly, or suddenly stop talking in the middle
of speech.

E

Social Withdrawal

Another common characteristic of schizophrenia is social withdrawal. People with schizophrenia may avoid others or act as though others do not exist. They often show
decreased emotional expressiveness. For example, they may talk in a low, monotonous voice, avoid eye contact with others, and display a blank facial expression. They
may also have difficulties experiencing pleasure and may lack interest in participating in activities.

F

Other Symptoms

Other symptoms of schizophrenia include difficulties with memory, attention span, abstract thinking, and planning ahead. People with schizophrenia commonly have
problems with anxiety, depression, and suicidal thoughts. In addition, people with schizophrenia are much more likely to abuse or become dependent upon drugs or

alcohol than other people. The use of alcohol and drugs often worsens the symptoms of schizophrenia, resulting in relapses and hospitalizations.

IV

CAUSES

Schizophrenia appears to result not from a single cause, but from a variety of factors. Most scientists believe that schizophrenia is a biological disease caused by genetic
factors, an imbalance of chemicals in the brain, structural brain abnormalities, or abnormalities in the prenatal environment. In addition, stressful life events may
contribute to the development of schizophrenia in those who are predisposed to the illness.

A

Genetic Factors

Research suggests that the genes one inherits strongly influence one's risk of developing schizophrenia. Studies of families have shown that the more closely one is
related to someone with schizophrenia, the greater the risk one has of developing the illness. For example, the children of one parent with schizophrenia have about a
13 percent chance of developing the illness, and children of two parents with schizophrenia have about a 46 percent chance of eventually developing schizophrenia. This
increased risk occurs even when such children are adopted and raised by mentally healthy parents. In comparison, children in the general population have only about a
1 percent chance of developing schizophrenia.

B

Chemical Imbalance

Some evidence suggests that schizophrenia may result from an imbalance of chemicals in the brain called neurotransmitters. These chemicals enable neurons (brain
cells) to communicate with each other. Some scientists suggest that schizophrenia results from excess activity of the neurotransmitter dopamine in certain parts of the
brain or from an abnormal sensitivity to dopamine. Support for this hypothesis comes from antipsychotic drugs, which reduce psychotic symptoms in schizophrenia by
blocking brain receptors for dopamine. In addition, amphetamines, which increase dopamine activity, intensify psychotic symptoms in people with schizophrenia. Despite
these findings, many experts believe that excess dopamine activity alone cannot account for schizophrenia. Other neurotransmitters, such as serotonin and
norepinephrine, may play important roles as well.

C

Structural Brain Abnormalities

Brain imaging techniques, such as magnetic resonance imaging and positron-emission tomography, have led researchers to discover specific structural abnormalities in
the brains of people with schizophrenia. For example, people with chronic schizophrenia tend to have enlarged brain ventricles (cavities in the brain that contain
cerebrospinal fluid). They also have a smaller overall volume of brain tissue compared to mentally healthy people. Other people with schizophrenia show abnormally low
activity in the frontal lobe of the brain, which governs abstract thought, planning, and judgment. Research has identified possible abnormalities in many other parts of
the brain, including the temporal lobes, basal ganglia, thalamus, hippocampus, and superior temporal gyrus. These defects may partially explain the abnormal thoughts,
perceptions, and behaviors that characterize schizophrenia.

D

Factors Before and During Birth

Evidence suggests that factors in the prenatal environment and during birth can increase the risk of a person later developing schizophrenia. These events are believed
to affect the brain development of the fetus during a critical period. For example, pregnant women who have been exposed to the influenza virus or who have poor
nutrition have a slightly increased chance of giving birth to a child who later develops schizophrenia. In addition, obstetric complications during the birth of a child--for
example, delivery with forceps--can slightly increase the chances of the child later developing schizophrenia.

E

Stressful Events

Although scientists favor a biological cause of schizophrenia, stress in the environment may affect the onset and course of the illness. Stressful life circumstances--such
as growing up and living in poverty, the death of a loved one, an important change in jobs or relationships, or chronic tension and hostility at home--can increase the
chances of schizophrenia in a person biologically predisposed to the disease. In addition, stressful events can trigger a relapse of symptoms in a person who already has
the illness. Individuals who have effective skills for managing stress may be less susceptible to its negative effects. Psychological and social rehabilitation can help
patients develop more effective skills for dealing with stress.

V

TREATMENT

Although there is no cure for schizophrenia, effective treatment exists that can improve the long-term course of the illness. With many years of treatment and
rehabilitation, significant numbers of people with schizophrenia experience partial or full remission of their symptoms.
Treatment of schizophrenia usually involves a combination of medication, rehabilitation, and treatment of other problems the person may have. Antipsychotic drugs
(also called neuroleptics) are the most frequently used medications for treatment of schizophrenia. Psychological and social rehabilitation programs may help people with
schizophrenia function in the community and reduce stress related to their symptoms. Treatment of secondary problems, such as substance abuse and infectious
diseases, is also an important part of an overall treatment program.

A

Antipsychotic Drugs

Antipsychotic medications, developed in the mid-1950s, can dramatically improve the quality of life for people with schizophrenia. The drugs reduce or eliminate
psychotic symptoms such as hallucinations and delusions. The medications can also help prevent these symptoms from returning. Common antipsychotic drugs include
risperidone (Risperdal), olanzapine (Zyprexa), clozapine (Clozaril), quetiapine (Seroquel), haloperidol (Haldol), thioridazine (Mellaril), chlorpromazine (Thorazine),
fluphenazine (Prolixin), and trifluoperazine (Stelazine). People with schizophrenia usually must take medication for the rest of their lives to control psychotic symptoms.
Antipsychotic medications appear to be less effective at treating other symptoms of schizophrenia, such as social withdrawal and apathy.
Antipsychotic drugs help reduce symptoms in 80 to 90 percent of people with schizophrenia. However, those who benefit often stop taking medication because they do
not understand that they are ill or because of unpleasant side effects. Minor side effects include weight gain, dry mouth, blurred vision, restlessness, constipation,
dizziness, and drowsiness. Other side effects are more serious and debilitating. These may include muscle spasms or cramps, tremors, and tardive dyskinesia, an
irreversible condition marked by uncontrollable movements of the lips, mouth, and tongue. Newer drugs, such as clozapine, olanzapine, risperidone, and quetiapine,
tend to produce fewer of these side effects. However, clozapine can cause agranulocytosis, a significant reduction in white blood cells necessary to fight infections. This
condition can be fatal if not detected early enough. For this reason, people taking clozapine must have weekly tests to monitor their blood.

B

Psychological and Social Rehabilitation

Because many patients with schizophrenia continue to experience difficulties despite taking medication, psychological and social rehabilitation is often necessary. A
variety of methods can be effective. Social skills training helps people with schizophrenia learn specific behaviors for functioning in society, such as making friends,
purchasing items at a store, or initiating conversations. Behavioral training methods can also help them learn self-care skills such as personal hygiene, money
management, and proper nutrition. In addition, cognitive-behavioral therapy, a type of psychotherapy, can help reduce persistent symptoms such as hallucinations,
delusions, and social withdrawal.
Family intervention programs can also benefit people with schizophrenia. These programs focus on helping family members understand the nature and treatment of
schizophrenia, how to monitor the illness, and how to help the patient make progress toward personal goals and greater independence. They can also lower the stress
experienced by everyone in the family and help prevent the patient from relapsing or being rehospitalized.
Because many patients have difficulty obtaining or keeping jobs, supported employment programs that help patients find and maintain jobs are a helpful part of
rehabilitation. In these programs, the patient works alongside people without disabilities and earns competitive wages. An employment specialist (or vocational
specialist) helps the person maintain their job by, for example, training the person in specific skills, helping the employer accommodate the person, arranging
transportation, and monitoring performance. These programs are most effective when the supported employment is closely integrated with other aspects of treatment,
such as medication and monitoring of symptoms.
Some people with schizophrenia are vulnerable to frequent crises because they do not regularly go to mental health centers to receive the treatment they need. These
individuals often relapse and face rehospitalization. To ensure that such patients take their medication and receive appropriate psychological and social rehabilitation,
assertive community treatment (ACT) programs have been developed that deliver treatment to patients in natural settings, such as in their homes, in restaurants, or on
the street.

C

Associated Problems

People with schizophrenia often have other medical problems, so an effective treatment program must attend to these as well. One of the most common associated
problems is substance abuse. Successful treatment of substance abuse in patients with schizophrenia requires careful coordination with their mental health care, so that
the same clinicians are treating both disorders at the same time.
The high rate of substance abuse in patients with schizophrenia contributes to a high prevalence of infectious diseases, including hepatitis B and C and the human
immunodeficiency virus (HIV). Assessment, education, and treatment or management of these illnesses is critical for the long-term health of patients.
Other problems frequently associated with schizophrenia include housing instability and homelessness, legal problems, violence, trauma and post-traumatic stress
disorder, anxiety, depression, and suicide attempts. Close monitoring and psychotherapeutic interventions are often helpful in addressing these problems.

VI

RELATED DISORDERS

Several other psychiatric disorders are closely related to schizophrenia. In schizoaffective disorder, a person shows symptoms of schizophrenia combined with either
mania or severe depression. Schizophreniform disorder refers to an illness in which a person experiences schizophrenic symptoms for more than one month but fewer
than six months. In schizotypal personality disorder, a person engages in odd thinking, speech, and behavior, but usually does not lose contact with reality (see
Personality Disorders). Sometimes mental health professionals refer to these disorders together as schizophrenia-spectrum disorders.

Contributed By:
Kim T. Mueser
Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft Corporation. All rights reserved.