Schizophrenia - Causes

People have argued for centuries about the causes of mental illnesses such as schizophrenia. Historically, people with these afflictions have been defined as "mad" or "insane" or were believed to be possessed by evil spirits. Those suffering from mental illness were often beaten, tortured, or locked up in special facilities.

For much of the twentieth century, scientists thought that stressful or traumatic conditions in a person's life could cause mental disorders. Psychiatrists believed that a neglected or abused child, for example, ran a higher risk of developing some mental disorders.

This theory is now less popular with scientists, who generally agree that the disease is biological and not caused by life experiences. There are, however, several competing theories as to what does cause the illness.

Heredity

Research shows that the condition tends to run in families. A person with schizophrenic relatives is ten times as likely to develop schizophrenia as someone who has no history of the disease in the family.

Viral Infection

Some researchers have argued that schizophrenia is caused by a virus that attacks the brain. The virus is thought to attack the part of the brain that interprets messages from the senses. Damage to this part of the brain may account for a person's delusions and hallucinations.

Chemical Imbalance

A popular theory is that schizophrenia is caused by an imbalance of neurotransmitters in the brain. Neurotransmitters (pronounced NOOR-oh-TRANZ-mit-urz) are chemicals that carry electrical messages between nerve cells. Too much of a neurotransmitter, or too little, may account for various mental disorders, including schizophrenia.

There is still no consensus (agreement) as to which, if any, of these theories is correct, or whether the disease is caused by a combination of factors.