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Evidence of genetic overlap of schizophrenia and bipolar disorder

A new scientific research study from the United States has presented presented more evidence of genetic overlap of schizophrenia and bipolar disorder.

The study suggests that the long-standing concept that schizophrenia and bipolar disorder represent two distinct illnesses has been recently challenged by findings of overlap of genetic susceptibility for these two diseases.

The researchers reported in their study an analysis of the genetic linkage analysis of chromosome 18 utilizing subjects with schizophrenia from the Central Valley of Costa Rica," scientists in the United States report," wrote C. Walssbass and colleagues, University of Texas, San Antonio.

The investigators explained, "Since both the schizophrenia and bipolar samples contained cases with a history of mania and almost all cases of schizophrenia and bipolar had a history of psychosis, we performed an alternative phenotyping strategy to determine whether presence or absence of mania, in the context of psychosis, would yield distinct linkage patterns along chromosome 18."

"This study illustrates the importance of detailed phenotype analysis in the search for susceptibility genes influencing complex psychiatric disorders in isolated populations and suggests that subdivision of psychoses by presence or absence of past mania syndromes may be useful to define genetic subtypes of chronic psychotic illness," Walssbass and coinvestigators concluded.

Source: American Journal of Medical Genetics Part B - Neuropsychiatric Genetics (Evidence of genetic overlap of schizophrenia and bipolar disorder: Linkage disequilibrium analysis of chromosome 18 in the Costa Rican population. Am J Med Genet B Neuropsychiatr Genet, 2005;139B(1):54-60).

More Information: Genes for schizophrenia and bipolar disorder? Implications for psychiatric nosology