Genetic explanations Flashcards
Over ____ specific common risk loci and at least ____rare risk alleles have been identified
Over 100 specific common risk loci and at least 11 rare risk alleles have been identified
Describe the mutational target for schizophrenia based on early sequencing studies.
Early sequencing studies suggest that the mutational target for schizophrenia is likely to be extensive involving hundreds and very likely thousands of genes (we know 110 are but not the rest)
What is the significance of SNP (single nucleotide polymorphisms) in genetics?
SNP (single nucleotide polymorphisms) are people’s most common genetic variation. Each SNP represents a difference in a single DNA nucleotide
On what chromosomes have psychotic symptoms been primarily identified according to Kendler (2000)?
Psychotic symptoms have been identified primarily on chromosomes 8 and 22 (Kendler 2000)
How do genetic linkage studies, twin studies, adoption studies, and family studies contribute to determining genetic influence?
These methods help in understanding the genetic influence by studying relationships, heritability, and patterns of inheritance.
(Schneider 2001)
Do individuals with a 1st-degree relative diagnosis of schizophrenia have a higher likelihood of developing psychotic symptoms?
Yes, individuals with a 1st-degree relative diagnosis are 10 times more likely to develop psychotic symptoms compared to those without such a diagnosis.
(Schneider 2001)
What did Ingraham (1994) find regarding adopted children and psychotic symptoms in relation to biological and adopted relatives?
Adopted children who develop psychotic symptoms are more likely to have had biological relatives diagnosed (21.4%)than adopted relatives diagnosed (5.4%)
AO3- Biologically reductionist, (Stefansson et al., 2003, 2002)
Neuregulin 1 (Nrg1)
Biological explanations for schizophrenia may be deemed as biologically reductionist. For instance, Neuregulin 1 (Nrg1) has been identified as a susceptibility gene for schizophrenia by genome-wide association studies in multiple populations (Stefansson et al., 2003, 2002). Associating schizophrenia solely to candidate genes oversimplifies the complex nature of the disorder. Schizophrenia is a multifaceted condition influenced by various genetic, environmental, and psychological factors. Reducing it to a single biological cause neglects the interplay of these factors in contributing to the development and maintenance of schizophrenic symptoms. Perhaps rather than attributing schizophrenia solely to candidate genes, a diathesis-stress model could be used to provide a more comprehensive explanation as it considers both genetic and environmental factors. Consequently, such models can be used by psychologists to gain a deeper understanding of schizophrenia and develop more effective treatments. Therefore, a more interactionist approach can be used to explain schizophrenia to account for its biological reductionism
AO3 – genetics overstated in twin studies
A further limitation of genetic explanations is that the role of genetics has been overstated in twin studies. For instance, it is nearly impossible to disentangle nature from nurture and consequently, it is not clear whether a higher concordance rate in MZ twins than DZ twins is due to genetics or rather due to MZ twins sharing a more similar environment than DZ twins. This is problematic as it makes it very challenging to draw concrete conclusions regarding the exact influence that genetics plays in the manifestation of schizophrenia. Some may argue that the utilisation of such methods limits the credibility of the evidence on offer. Perhaps psychologists should instead focus on conducting adoption studies as this shortcoming does not extend to such methods. Therefore, some research examining the role of genetics in schizophrenia may fall foul of methodological flaws associated with the use of twin studies.
