This article looks at the different methods that can and have been used to find genetic links to the liability of bipolar and the possibility that the same genes that can cause schizophrenia may also cause Bipolar do to both these disorders displaying some of the same symptoms and possible co-morbidity. There is evidence of an overlap in both these disorders especially in psychotic and depressive symptoms such as hallucination, delusions, disorganised thought and catatonic behaviour.
The paper goes through a few methods of research that have been explored and suggests that further exploration should be carried out on these. I identifying shared risk genes using recombination frequencies to infer distances between genetic markers and target risk loci by using association studies on genetic polymorphism, using more single nucleotide polymorphisms for this.
Endophenotyes are also suggested as a point of study. This is a psychiatric concept of a bio marker divided into behavioural symptoms. These a different types of neurological components and cognitive components of assertions. One of these smaller phenotypes is classified as a deficiency of smooth pursuit of eye movement caused by a number of genes tied into schizophrenia and dopamine. This paper also outlines different research results done on the gene marks of both these disorders including twin and family studies as well as dopamine.
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