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Schizophrenia: An Overview

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What Causes Schizophrenia?

The exact cause of schizophrenia is not yet known. It is known, however, that schizophrenia -- like cancer and diabetes -- is a real illness with a biological basis. It is not the result of bad parenting or personal weakness. Researchers have uncovered a number of factors that appear to play a role in the development of schizophrenia, including:

  • Genetics (heredity): Schizophrenia tends to run in families, which means a greater likelihood to develop schizophrenia may be passed on from parents to their children.
  • Brain chemistry and circuits: People with schizophrenia may have abnormal regulation of  certain chemicals (neurotransmitters) in the brain, related to specific pathways or "circuits" of nerve cells that affect thinking and behavior. Different brain circuits form networks for communication throughout the brain.  Scientists think that problems with how these circuits operate may result from trouble with certain receptors on nerve cells for key neurotransmitters (like glutamate, GABA, or dopamine), or with other cells in the nervous system (called "glia") that provide support to nerve cells within brain circuits.  The illness is not believed to be simply a deficiency or "imbalance" of brain chemicals, as was once thought.
  • Brain abnormality: Research has found abnormal brain structure and function in people with schizophrenia. However, this type of abnormality doesn't happen in all schizophrenics and can occur in people without the disease.
  • Environmental factors: Evidence suggests that certain environmental factors, such as a viral infection, extensive exposure to toxins like marijuana, or highly stressful situations, may trigger schizophrenia in people who have inherited a tendency to develop the disorder. Schizophrenia more often surfaces when the body is undergoing hormonal and physical changes, such as those that occur during the teen and young adult years.

Who Gets Schizophrenia?

Anyone can get schizophrenia. It is diagnosed all over the world and in all races and cultures. While it can occur at any age, schizophrenia typically first appears in the teenage years or early 20s. The disorder affects men and women equally, although symptoms generally appear earlier in men (in their teens or 20s) than in women (in their 20s or early 30s). Earlier onset of symptoms has been linked to a more severe course of illness. Children over the age of 5 can develop schizophrenia, but it is very rare before adolescence.

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