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Chapter 2

PSYB32H3 Chapter Notes - Chapter 2: Neurology, Meninges, Biopsychosocial Model

Course Code
Konstantine Zakzanis

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Chapter 2
Paradigm- the conceptual framework or approach within which the scientist works. A paradigm is a set of basic
assumptions that outline the particular universe of scientific inquiry
Paradigms specify what problems scientists will investigate and how they will go about the investigation. They
serve the vital function of indicating the rules to be followed
A paradigm injects inevitable biases into the definition and collection of data and may also affect the
interpretation of facts
There are 5 paradigms: biological, psychoanalytical, humanistic and existential, learning and cognitive
Current thinking about abnormal beh tends to be multi faceted and tend to integrate several paradigms
Biological paradigm- a broad theoretical view that holds that mental disorders are caused by some aberrant
somatic process or defect. Its continuous of the somatoegnic hypothesis.
The paradigm has often been referred to as the medical model or disease model
The study of ab beh is linked historically to medicine
For a time the germ theory was the paradigm of medicine but it soon became apparent that this theory could not
account for all diseases. Heart disease is one example. Medical illnesses can differ from one another in causes but
they all share one characteristic: in al of them some bio process is disrupted or not functioning normally. That’s
why its called the bio paradigm
The bio paradigm was the dominant paradigm in Canada and elsewhere from the late 1800s until at least the
middle of the 20th cen
Hall; use of gynaecological procedures to treat “insanity” in women from B.C. he maintained that insanity exists
when the Ego is dominated and controlled by the influence from a diseased periphery nerve tract or centre.. the
removal of a small part of the physical disease might result in the restoration of the balance of power to such an
organism and diminish if not remove the ab psychic phenomena. Removal of ovarian cysts or the entire ovaries
was employed as treatment for melancholia, mania and delusions
Contemporary approaches to the biological paradigm
Hereditary probably predisposes a person to have increased risk of developing schizto, depression may result
from chemical imbalances within the brain, anxiety disorders may stem from a defect within the automatic NS
that causes a person to be too easily aroused and dementia can be traced to impairments in structures of the brain
In each case the psychopathology is viewed as caused by the disturbance of some bio process
Behaviour Genetics
When the ovum, female reproductive cell is joined by the male’s spermatozoon, a zygote or fertilized egg is
It has 46 chromosomes, the # of characteristics of a human being
Each chromosome is made up of thousands of genes, the carriers of the genetic information (DNA) passed from
parents to child
Gene- an ultramicroscopic area of the chromosome; the gene is the smallest physical unit of the DNA molecule
that carries a piece of hereditary information
Behavioural genetics is the study of individual differences in beh that are attributable in part to differentiate in
genetic makeup. It studies the degree to which characteristics such as psychical resemblance or psychopathology
are shared by family members cuz of shared genes
The total genetic makeup of an individual consisting of inherited genes is referred to as the genotype
Genotype- an indiv unobservable genetic constitution; the totality of genes possessed by an indib
Phenotype- the totality of the persons observable, beh characterises such as the level of anxiety.
The genotype is fixed at birth but it should not be viewed as a static entity
The phenotype changes over time and is viewed as the product of an interaction between the genotype and the

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Any measure of intelligence is best viewed as an index of the phenotype
Its critical to recognize that various clinical syndromes are disorders of the phenotype not of the genotype
Only the genotypes for these disorders can be inherited. Whether the genotype will eventually will come out in
the phenotypic beh disorder depends on environment and experience.
A predisposition also known as a diathesis may be inherited but not the disorder itself
The study of genetics has relied on 4 basic methods to uncover whether a predisposition for psychopathology is
inherited: comparison of members of a family, comparison of pairs of twins, the investigation of adoptees, and
linkage analysis
The family method can be used to study a genetic predisposition among members of a family cuz the average #
of genes shared by two blood relative is known
Parents and kids are identical in 50% of their genetic background. Ppl who share 50% of their genes with a given
person are called first degree relatives of that person
Nephews and nieces share 25% of the genetic makeup of an uncle and are called second degree relatives
A sample of ppl who bear the diagnosis in question- these ppl are referred to as index cases or probands
If the genetic predisposition being studied is present 1st degree relatives of the index cases should have the
disorder at a higher rate than that found in the general population. Ex: about 10% of the 1st degree relatives of
index cases with schitzo can be diagnosed as having shcitzo compared with about 1% of the general population
In the twin method both monozygotic (MZ) twins and dizygotic (DZ) twins are compared. MZ twins develop
from a single fertilized egg and are genetically the same
DZ or fraternal develop from separate eggs and are on average only 50% alike genetically
MZ twins are always the same sex but DZ twins can be either the same or opposite
When the twins are similar diagnostically they are said to be concordant
If its said that a predisposition for a mental disorder can be inherited , concordance should be greater in
genetically identical MZ pairs than in DZ pairs. When the MZ concordance rate is higher than the DZ rate the
characteristics being studied is said to be heritable
Data shows that panic disorder runs in families but that a genetic predisposition is not necessarily involved
Equal environment assumption is that the environmental factors that are partial causes of concordance are equally
influential for MZ pairs and DZ pairs. This seems to be reasonable
Other factors can complicate the resulted of twin research. Study of post traumatic stress disorder in community
residents stein identified 3 factors as biasing heritably estimates: violation of the equal environment assumption,
sex of the participant, and his or her age when the assessment took place
Only environmental factors contributed to exposure to events involving non assulative traumas ( car accidents)
but genetic and enviro factors contributed to exposure to assualtive traumas (sexual assaults)
This genetic factors may determine the extent to which a person is likely to experience post traumatic stress after
an assualtive trauma
This is the 1st study to examine this issue in a non military sample and the 1st to include women but its limited cuz
rely on self report measures of trauma
Using the adoptees method study kids who were adopted and reared apart from their parents with ab disorders. If
a high frequency of panic disorder were found in kids reared apart from parents who also had it could have
support for theory that genetic predisposition is in the works
Molecular Genetics
Tries to specify the particular gene or genes involved and the precise functions of these genes
Each cell consists of 46 chromosomes (23) pairs with thousands of genes per chromosome. The term allele refers
to any one of several DNA codings that occupy the same position or location on a chromosome. A persons
genotype is their set of alleles
The term genetic polymorphism refers to variability among members of the species. It involves differences in the
DNA sequence that can manifest in very dif forms among members of the same habitat. It entails mutations in a
chromosome that can be induced or naturally occurring
It was discovered in 2004 with research on male meadow voles that manipulating a gene, the vasopressin receptor
by locating it in the reward centre of the brain had the effect of making an amorous promiscuous vole into a
monogamous vole. Its possible a similar process determines whether humans refrain from having more than 1

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Linkage analysis is a method in molecular genetics hat is used to study ppl. Use this method in families in which
a disorder is heavily concentrated
they collect diagnostic info and blood samples from affected indiv and their relatives and use them to study the
inheritance patter of characteristics whose genetics are fully understood referred to as genetic markers ex: eye
colour is controlled by a gene in a specific location on a specific chromosome
it is concluded that the gene predisposing indi to the psychopathology is on the same chromosome and in similar
location on that chromate (its linked) as the gene controlling the other chracterticsi
linkage analysis in t.o found association btwn obsessive compulsive disorder and the gamma aminobutyric acid
(GABA) type B receptor 1 (GABBR1) gene
greatest success is to identify genes that are imp in alzhinermers
study of genetic linkage in adolescents and young adults indicated that a locus on chromosome 9 is associated
with enhanced risk for externalizing psychopathology (aggression and conduct disorder)
gene environment interactions – notion that a disorder or related symptoms are the joint product of a genetic
vulnerability and specific environmental experiences or conditions
Neuroscience and biochemistry in the Nervous system
the NS is composed of billions of neurons
neurons diff in some ways each neuron has four major parts: 1) the cell body 2) several dendrites 3) three or
more axons of varying lengths 4) terminal buttons on many end branches of the axon
when a neuron is stimulated at its cell body or through its dendrites a nerve impulse which is a change in the
electric potential of the cell travels down the axon to the terminal endings
between the terminal endings f the sending axon and the cell membrane of the receiving neuron there is a small
gap called the synapse
for a nerve impulse to pass from one neuron to another and for communication to occur the impulse must have a
way of bridging the synaptic gap
the terminal buttons of each axon contain synaptic vesicles, small structures that are filled with
neurotransmitters, chemical substances that allow a nerve impulse to release molecules of their transmitter
substances and these molecules flood the synapses and diffuse toward the receiving or postsynaptic neuron
the cell membrane of the postsynaptic cell contains proteins called receptor sites that are configured so that
specific neurotransmitters can fit into them
when a neurotransmitter fits into a receptor site a message can be sent to the postsynaptic cell. What actually
happens to the postsynaptic neuron depends on its integrating thousands of similar messages
sometimes the messages are excitatory leading to the creation of a nerve impulse in the postsynaptic cell at other
times the messages can be inhibitory making the postsynaptic cell less likely to fire
once a presynaaptic neuron (the sending neuron) has released its neurotransmitter the last step is for the synapse
to be returned to its normal state
not all of the released neurotransmitter has found its way to postsynaptic receptors. Some of what remains in the
synapses is broken down by enzymes and some is pumped back into the presynaptic cell through a process called
norepinephrine a neurotransmitter of the peripheral sympathetic nervous system is involved in producing states of
high arousal and thus may be involved in anxiety disorders
both serotonin and dopamine are neurotransmitters in the brain. Serotonin may be involved in depression and
dopamine in schitzo. GABA inhibits some nerve impulses and maybe involved in anxiety disorders
puberty in adolescents results in a decrease in serotonin and a decrease in dopamine activity in certain cortical
some of the theories linking neurotransmitters to psychopathology have proposed that a given disorder is caused
by either too much or too little of a particular transmitter (mania results from too much norepinephrine and
anxiety disorders from too little GABA)
neurotransmitters are synthesized in the neuron through a series if metabolic steps beginning with amino acid
too much or too little of a particular transmitter could result from an error in these metabolic pathways. Similar
disturbances in the amounts of specific transmitters could result from alterations in the usual processes by which
transmitters are deactivated after being released into the synapse
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