Schizophrenia Definition: Schizophrenia is a chronic, severe, and disabling brain disorder.  It is estimated to affect 2.2 million (1.1%) Americans aged 18 and over.  Schizophrenia affects an individual’s capability to think clearly, differentiate reality from fantasy, to handle emotions, make decisions and interact with others.  Schizophrenia tends to appear in the teenage years or early twenties.  Individuals who have schizophrenia suffer chronically or episodically throughout their lives. Due to a lack of public awareness people with schizophrenia are often stigmatized.  Schizophrenia is not caused by bad parenting or a personal weakness; most individuals with schizophrenia are not dangerous or violent towards others whilst receiving treatment.    It is still unknown what causes schizophrenia; research has indicated that the brains of people with schizophrenia are different from other individuals.  It is thought that Schizophrenia, like many other diseases, is caused by a mixture of problems such as genetic vulnerability and environmental factors that are present during a person’s development.   Researchers have identified the genes that increase a person’s predisposition to this disease.  The genes do not directly cause schizophrenia; rather they increase the likelihood of developing it.  Schizophrenia is known to run in families, the risk of an identical twin developing this illness is about 40-50%.  The risk of a child of a parent suffering from schizophrenia has a 10% of developing the illness.  The risk in the general population is about 1%.    Scientists have identified small changes in the brain structure and functioning.  This could mean that this illness maybe a disorder of the brain development.