Schizophrenia is a serious brain disorder that distorts the way a person thinks, acts, expresses emotions, perceives reality, and relates to others. People with schizophrenia -- the most chronic and disabling of the major mental illnesses -- often have problems functioning in society, at work, at school, and in relationships. Schizophrenia can leave its sufferer frightened and withdrawn. It is a life-long disease that cannot be cured but can be controlled with proper treatment.