Week 1 Chapter 2 Current Paradigms in Psychopathology CF Flashcards
To aid learning of Chapter 2
What is a paradigm?
A paradigm is a conceptual framework or set of assumptions that defines how to conceptualise & study a subject; how to gather & interpret relevant data, even how to think about a particular subject
What are 3 paradigms that guide the study & treatment of psychopathology?
3 paradigms that guide the study & treatment of psychopathology are
- Genetic
- Neuroscience
- Cognitive Behavioural
paradigms. For most disorders, each paradigm offers some important information with respect to aetiology & treatment, but only provide part of the picture
What are 2 other factors that cut across all the paradigms and are significant in terms of the description, causes, and treatment of all the disorders?
2 other factors that cut across all the paradigms are socio-cultural factors and emotional factors
What does Shenk (2010) say of genes?
Genes do not, on their own, make us smart, dumb, sassy, polite, depressed, joyful, musical tone-deaf, athletic, clumsy, literary or incurious. Those characteristics come from a complex interplay within a dynamic system. Every day in every way you are helping to shape which genes become active. Your life is interacting with your genes.
What are the 2 key aspects that make up the genetic paradigm?
- almost all behaviour is heritable to some degree (i.e. involves genes)
- genes do not operate in isolation from the environment. Instead, through the lifespan, the environment shapes how our genes are expressed, and our genes also shape our environment
What does it mean to think about genes and the environment as ‘nature via nurture’?
We are considering how environmental influences, such as stress, relationships, & culture (nurture), shape which of our genes are turned on or off & how our genes (nature) influence our bodies & brain
What are genes?
- Genes are the carries of the genetic information (DNA)
- Genes makes proteins that in turn make the body & brain work
- It is the sequencing, or ordering, of these genes as well as their expression that make us unique
What is gene expression?
- Gene expression is the process where proteins switch genes on or off
- Gene expression is related to how your genes interact with your environment
Psychopathology is polygenic. What does this mean?
Several genes, perhaps operating at different times during the course of development, are turning themselves on & off as they interact with a person’s environment - this is the essence of genetic vulnerability & establishes that we do not inherit mental illness from our genes, rather, we develop mental illness through the interaction of our genes with our environment
What does heritability refer to?
Heritability refers to the extent to which variability in a particular behaviour (or disorder) in a population can be accounted for by genetic factors.
What are 2 important considerations to be aware of with regard heritability?
- heritability estimates range from 0.0 to 1.0 - the higher the number, the greater the heritability
- Heritability is relevant ONLY for populations not a particular individual. Thus it is incorrect to talk about any on person’s heritability for a particular disorder. Knowing the heritability for ADHD is 0.7 does not mean 70% of James’ ADHD came from his genes & 30% from the environment. It means that in a population, the variation of ADHD is understood as being attributed to 70% genes & 30% environment. There is no heritability in ADHD (or any disorder) for a particular individual
Other factors that are just as important as genes in genetic research are environmental factors.
What are Shared environments?
Shared environment factors include those things that members of a family have in common such as family income level, child-rearing practices, and parents martial status and parenting quality.
Other factors that are just as important as genes in genetic research are environmental factors.
What are Non-Shared or Unique Environments?
Non-Shared environmental factors are those things believed to be distinct among members of a family, such as relationships with friends, or events specific to an individual (e.g. car crash or athletic club membership). These are believed to be important in understanding why 2 siblings from the same family can be so different.
What are two broad approaches in the genetic paradigm?
Two broad approaches in the genetic paradigm are *behaviour genetics and
*molecular genetics
What is behaviour genetics?
Behaviour genetics is the study of the degree to which genes & environmental factors influence behaviour, rather than HOW genes or the environment determine behaviour
What is a genotype?
- Genotype is the total genetic make up of an individual, consisting of inherited genes
- the physical sequence of DNA
- The genotype cannot be observed outwardly
What is a phenotype?
- The phenotype is the totality of observable behavioural characteristics, such as level of anxiety
- The Phenotype changes over time & is the product of an interaction between the genotype and the environment
What did Turkheimer & colleagues find in 2003 when they studies how genes and environment may interact to influence IQ?
- They found that heritability depends on environment
- among low SES families 60% of variability in children’s IQ was attributable to the environment
- among high SES families the opposite was found
- Thus, variability in IQ was more attributable to genes than the environment
What do molecular genetics studies seek to identify?
Molecular genetics studies seek to identify particular genes and their functions
How many chromosomes does a human being have?
- A human being has 46 chromosomes (23 pairs)
* Each chromosome is made up of hundreds of thousands of genes that contain DNA
What is an allele?
- Different forms of the same gene are called alleles.
* The alleles of a gene are found at the same location or locus of a chromosome pair
What is a genetic polymorphism?
A genetic polymorphism refers to a difference in DNA sequence on a gene that has occurred in a population
Tell me a little about DNA and Gene expression & how they relate to the study of molecular genetics & psychopathology
- The DNA in genes is transcribed to RNA,
- In some cases, the RNA is then translated into amino acids, which then form proteins, & proteins make cells
- Gene expression involves particular types of DNA called promoters which are recognised by particular proteins called transcription factors
- Promoters & transcription factors are the focus of much research in molecular genetics & Psychopathology
In the past 10 years, molecular genetics research has focused on identifying differences between people in the sequence of the genes and in the structure of their genes.
What are single nucleotide polymorphisms (SNP’s - pronounces snips) & how are they important to molecular genetics research?
- A SNP refers to differences between people in a single nucleotide (A, T, G, C).
- SNP’s ae the most common type of polymorphisms in the human genome, with nearly 10 million different SNP’s identified thus far
- SNP’s have been studied in schizophrenia, autism, & the mood disorders
What are Copy Number Variations (CNVs)?
- CNVs are an abnormal copy of one or more section of the DNA within the gene(s).
- These abnormal copies can be additions (extra copies) or deletions (missing copies)
- as much as 5% of the human genome contains CNVs, which can be inherited from parents or can be spontaneous mutations, appearing for the first time in individuals
- CNVs have been studied in schizophrenia, autism & ADHD
What are knockout studies?
- Knockout studies are where researchers actually manipulate specific genes& then observe the effects on behaviour
- Specific genes can be taken out of mice DNA e.g. the specific gene responsible for neurotransmitter serotonin (5-HT1A) has been knocked out of mice before birth; as adults they show an anxious phenotype.
- Another study temporarily knocked 5-HT1A out & found its restoration early in development still produced anxious behaviour in adult mice
What is a gene-environment interaction?
*A gene-environment interaction means that a given person’s sensitivity to an environmental event is influenced by genes