Inheritance of the schizophrenia and bipolar affective disorder (BPD) are considered as multigene in which many gene regions interact with the environmental factors. The differential diagnosis between schizophrenia and BPD has been a major factor in the clinical evaluation of psychosis for many years. The development of molecular genetic techniques at the beginning of the 2000’s has provided high-budget and extensive genetic research. Knowledge about the human genome has risen through the genetic researches and many risk alleles associated with multigene inherited diseases have been found. The course of genetic research has started with the Human Genome Project and reached its peak with the Genome Wide Association Studies (GWAS) in 2000’s. A remarkable finding of genetic studies in psychiatry was many common gene loci between schizophrenia and BPD which were considered as completely different disorders. The importance of the genetic studies will probably increase considering the cases in which differential diagnosis is challenging for psychiatrists. Current data about the genetics of schizophrenia and its impact on clinical practice are intended to be revised in this review.
