Schizophrenia is a mental disorder that makes it difficult to tell the difference between real and unreal experiences, to think logically, to have normal emotional responses, and to behave normally in social situations.

Schizophrenia is a complex illness. Even experts in the field are not sure what causes it. Some doctors think that the brain may not be able to process information correctly.

Genetic factors appear to play a role. People who have family members with schizophrenia may be more likely to get the disease themselves.

Some researchers believe that events in a person's environment may trigger schizophrenia. For example, problems (infection) during development in the mother's womb and at birth may increase the risk for developing schizophrenia later in life.

Psychological and social factors may also affect its development. However, the level of social and family support appears to affect the course of illness and may protect against the condition returning.

There are 5 types of schizophrenia:

• Catatonic
• Disorganized
• Paranoid
• Residual
• Undifferentiated

Schizophrenia usually begins before the age of 45, symptoms last for 6 months or more, and people start to lose their ability to socialize and work.

Schizophrenia is thought to affect about 1% of people worldwide.

Schizophrenia appears to occur in equal rates among men and women, but in women it begins later. For this reason, males tend to account for more than half of patients in services with high numbers of young adults. Although schizophrenia usually begins in young adulthood, there are cases in which the disorder begins later (over 45 years).

Childhood-onset schizophrenia begins after the age of 5 and, in most cases, after normal development. Childhood schizophrenia is rare and can be difficult to tell apart from other developmental disorders of childhood, such as autism.

Schizophrenia may have a variety of symptoms. Usually the illness develops slowly over months or even years.

At first, the symptoms may not be noticeable. For example, you may feel tense, or have trouble sleeping or concentrating. You can become isolated and withdrawn, and have trouble making or keeping friends.

As the illness continues, psychotic symptoms develop:

• An appearance or mood that shows no emotion (flat affect)
• Bizarre motor behavior in which there is less reaction to the environment (catatonic behavior)
• False beliefs or thoughts that have nothing to do with reality (delusions)
• Hearing, seeing, or feeling things that are not there (hallucinations)
• Thoughts "jump" between unrelated topics (disordered thinking)

Symptoms can be different depending on the type of schizophrenia.

Catatonic type:

• Agitation
• Decreased sensitivity to pain
• Inability to take care of personal needs
• Negative feelings
• Motor disturbances
• Rigid muscles
• Stupor

Paranoid type:

• Anger
• Anxiety
• Argumentativeness
• Delusions of persecution or grandeur
• Violence

Disorganized type:

• Child-like (regressive) behavior
• Delusions
• Flat affect
• Hallucinations
• Inappropriate laughter
• Not understandable (incoherence)
• Repetitive behaviors
• Social withdrawal

Undifferentiated type may include symptoms of more than one type of schizophrenia.

Residual type -- symptoms of the illness have gone away, but some features, such as hallucinations and flat affect, may remain.

Because other diseases can cause symptoms of psychosis, psychiatrists should make the final diagnosis. The diagnosis is made based on a thorough interview of the person and family members.

No medical tests for schizophrenia exist. The following factors may suggest a schizophrenia diagnosis, but do not confirm it:

• Course of illness and how long symptoms have lasted
• Changes from level of function before illness
• Developmental background
• Genetic and family history
• Response to medication

CT scans of the head and other imaging techniques may find some changes that occur with schizophrenia and may rule out other disorders.

During an episode of schizophrenia, you may need to stay in the hospital for safety reasons, and to provide for basic needs such as food, rest, and hygiene.

Antipsychotic or neuroleptic medications change the balance of chemicals in the brain and can help control the symptoms of the illness. These medications are effective, but they can have side effects. However, many of these side effects can be addressed, and should not prevent people from seeking treatment for this serious condition.

Common side effects from antipsychotics may include:

• Sleepiness (sedation)
• Weight gain

Other side effects include:

• Feelings of restlessness or "jitters"
• Problems of movement and gait
• Muscle contractions

Long-term risks include a movement disorder called tardive dyskinesia, in which people move without meaning to.

Newer drugs known as atypical antipsychotics appear to have fewer side effects. They also appear to help people who have not improved with the older medications. Treatment with medications is usually needed to prevent symptoms from coming back.

Supportive and problem-focused forms of therapy may be helpful for many people. Behavioral techniques, such as social skills training, can be used during therapy, or at home to improve function socially and at work.

Family treatments that combine support and education about schizophrenia (psychoeducation) appear to help families cope and reduce the odds of symptoms returning. Programs that emphasize outreach and community support services can help people who lack family and social support.

Most people with schizophrenia find that their symptoms improve with medication, and some can get good control of their symptoms over time. However, others have functional disability and are at risk for repeated episodes, especially during the early stages of the illness.

To live in the community, people with schizophrenia may need supported housing, work rehabilitation, and other community support programs. People with the most severe forms of this disorder may be too disabled to live alone, and may need group homes or other long-term, structured places to live.

• People with schizophrenia have a high risk of developing a substance abuse problem. Use of alcohol or other drugs increases the risk of relapse.
• Physical illness is common among people with schizophrenia due to side effects from medication and living conditions. These may not be detected because of poor access to medical care and difficulties talking to health care providers.
• Not taking medication will often cause symptoms to return.

Call your health care provider if:

• Voices are telling you to hurt yourself.
• You are feeling hopeless and overwhelmed.
• You are seeing things that aren't really there.
• You feel like you cannot leave the house.
• You are unable to care for yourself.

The best way to prevent symptoms from coming back is to take the medication your doctor prescribed.

Because side effects are one of the most important reasons why people with schizophrenia stop taking their medication, it is very important to find the medication that controls your symptoms without causing side effects. Always talk to your doctor if you are thinking about changing or stopping your medications.

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