State of Art Flashcards
What is a paradigm?
A model/ conceptual framework of how we think things work
It impacts how we collect, analyse and interpret information
What are the three main paradigms in psychopathology?
- Genetic
- Neuroscience
- Cognitive behavioural
What’s the Genetic paradigm?
Genes contribute to risk for psychological disorders
23 pairs of chromosomes and the last pair is either
XX- women
XY- male
The rest are all the same
Chromosomes are made up of DNA
In DNA genes determine a characteristic, ie. Phenotype, hair or eye colour
Genes make proteins that our body needs to function , especially the brain
What is gene expression
Genotype- the genetic makeup of an organism
turns into
Phenotype - individuals observable traits
What are other contributors to the genetic paradigm?
The environment
Behavioural genetics
The role of the environment in genetics
The environment, ie. stress, relationships, healthcare etc, influences how genes are expressed
Genes and the environment don’t make anything happen independently, they interact with each other.
Everything about us depends both on our genes and on the environment in which our genes are expressed.
Gene-Environment Interactions
Give an example
Genes may pre-dispose us to seek out or become exposed to a certain environment that may change the way in which the gene is expressed.
Example:
Fraternal twins both have genes that give them a risk of depression.
because they’re not identical their genes aren’t all the same.
One of the twins has a genetic predisposition to introversion.
A different gene will change the environmental setting in which you live.
Introvert- might find it difficult to find new friends
Extrovert- might establish a support system everywhere they go.
What is behavioural genetics?
The study of the degree to which genes and the environment influence behaviour.
What is heritability?
reflects the extent to which variation in observed behaviour can be accounted for by genetic factors.
It’s a population concept- if you have a trait that has a heritability of 0.4, 40% of the variability is accounted for by genes
Doesn’t mean that 40 percent of the disorder is caused by genes
What’s an example of heritability?
seeds, one with nutrient deficient others without
the differences between the plants are completely different.
2 different estimates whether you study the entire plant group together vs you look at them separately.
How is heritability estimated
Twin studies
Identical- monozygotic- share 100 percent of genes
Fraternal- dizygotic- share 50% of their genes
One popular method is to compare identical and non-identical twins in terms of concordance (sameness in a trait)
But they shared their environment…
Another is to compare identical twins, reared apart or no shared environment( controlling genetic info but changing environment)
What did Turkeimer et al 2003 posit.
Variation in intelligence in poor families has more to do with environment and less with genes
The reverse is true for kids who grow up in wealthy families.
High SES identical have the same IQ
Low SES identical have different IQ
Fraternal high SES and low SES have similar
What is molecular genetics
The study of what is heritable by identifying specific genes and describing how they work.
Seeks to identify differences between people in the structure and expression of DNA
What is a polymorphism?
Any difference in the nucleotide sequence between individuals, ie. Blood type
These differences can be single base pair changes, deletions, insertions, or even changes in the number of copies of a given DNA sequence.
What’s a nucleotide?
Building blocks in DNA
What is a single nucleotide polymorphism?
(SNPs, pronounced ‘snips’)
are single base pair changes, the most common type.- looking at changes from one person to another
What are the 2 main research methods for the genetic paradigm?
- Knockout animals
- Comparing humans with different allele combinations
What is knockout animals?
Its called knockout studies because a specific gene is knocked out of the animals system
Example of knockout studies
the gene that is responsible for a specific receptor for the neurotransmitter serotonin,
called 5-HT1A can be knocked out in mice before their birth.
Results in an anxious phenotype when they are an adult.
Elevated plus maze:
They spend more time in the closed arms, ie. exhibit less exploration
Compare humans with different allele combinations
Focusing on serotonin, looking at the specific region of the gene and compare ppl with differences in the gene
Comparing ppl with 2 short alleles that makes it work less well v ppl with long ones allows it to work better
Overview of the genetic paradigm
Most disorders are polygenic
genetic factors likely increase vulnerability rather than determining whether or whether or not it occurs
Just because disorders are heritable, doesn’t mean that everyone with a biological risk marker will develop a disorder.
Combination of altered genes and poor environment gives rise to increased risk of disorder
What does polygenic mean?
Multiple genes are involved, each with small effects
What does the neuroscience paradigm posit?
What things are involved in this analysis
Psychological disorders are caused by abnormalities in the brain
Involve:
Neurotransmitters
Brain structure and function
Neuroendocrine system,ie. how we respond to threats
Beware of false dichotomies between paradigms
Biological, Psychological and Social paradigms are just different levels of analysis
What are neurons?
Messengers of the nervous system
Neurons use electrical nerve impulses called action potentials
There are 86 billion neurons in the brain
Its made up of a cell body, dendrites and an axon
