Schizophrenia is a mental disorder marked by the loss of contact with reality. When a person’s thinking, feeling, and behavior is so far from normal as to interfere with his or her ability to function in everyday life, and delusions, hallucinations, irregular thinking or emotions are produced, then he or she has a mental illness called schizophrenia.About one hundred years ago schizophrenia was first recognized as a mental disorder and researchers have been searching for a cure since. The exact cause of schizophrenia is still unknown and scientists are certain that schizophrenia has more than one cause. Scientists have developed dozens of theories to explain what causes this disease, but researchers are focusing on four leading theories. They are the Genetic Theory, the Enivronmental Theory, the Biochemical Theory, and the Bio-Psycho-Social Theory.The Genetic Theory argues that schizophrenia is caused by traits in a person’s genetic makeup. As we all know, a person has twenty-three pairs of chromosomes. Each pair contains one chromosome from each parent. In corresponding locations, called loci, of each chromosome the genes for specific traits are located. Some researchers believe that problems with these genes can cause schizophrenia. We inherit our genes from our parents but this does not mean that the parents of a schizophrenic are mentally ill. Problems in a persons genetic make up could come from mutated chromosomes or recessive genes. In an attempt to prove this theory scientists study identical twins. Bue to the fact that identical twins have the exact same genetic make up researchers will be able to determine if heredity is the main cause of schizophrenia. However, evidence seems to desprove this theory. This is because on some occasions both identical twins are schizophrenics and other times only one is inflicted. To defend the theory, it should be noted that this research is difficult and complicate...