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Chapter 2

PSYB32H3 Chapter 2: Chapter-2_b32

Course Code
Konstantine Zakzanis

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Chapter 2: Current Paradigms and Integrative Approaches (pg.67-120)
2.1 The Role of Paradigms
A paradigm is 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
Four major types of paradigms: biological, cognitive-behavioural, psychoanalytic, and
2.2 The Biological Paradigm
The biological paradigm of abnormal behaviour is a continuation of the somatogenic
hypothesis (that mental disorders are caused by aberrant biological processes). This
paradigm has been referred to as the medical model or disease model.
Medical illnesses can vary widely but they all share one common characteristic: in all of
them, some biological process is disrupted or not functioning normally. Hence,
‘biological paradigm.’
Contemporary Approaches to the Biological Paradigm
Heredity predisposes a person to have an increased risk of developing schizophrenia,
depression may result from chemical imbalance within brain, anxiety may stem from a
defect within the ANS that causes a person to be easily aroused etc.
In each case above, psychopathology is viewed as caused by the disturbance of some
biological process
1) Behaviour Genetics
o Each chromosome is made up of thousands of genes, the carriers of the
genetic information (DNA) passed from parents to child
o Behaviour genetics is the study of individual differences in behaviour that are
attributable in part to differences in genetic makeup
o The total genetic makeup of an individual, consisting of inherited genes is
genotype. An individual’s genotype is his or her unobservable genetic
constitution. Genotype is fixed at birth but should not be viewed as a static
o An individual’s phenotype is the totality of his or her observable, behavioural
characteristics (eg. anxiety). Phenotype changes over time and is viewed as a
product of an interaction between genotype and the environment. (eg.
individual may be born with high intellect but whether he/she develops this
genetically, depends on environmental factors like upbringing and education)
o Various clinical symptoms are disorders of phenotype, not genotype!
o A predisposition, known as diathesis may be inherited, but not the disorder
o The family method can be used to study a genetic predisposition among
members of a family bc the average number of genes shared by two blood
relatives is known. (50% from mom, 50% from dad)
o The starting point in investigations is the collection of a sample of individuals
who bear the diagnosis in question. These people are referred to as index
cases or probands.

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o In the twin method, both monozygotic twins (identical twins developed from
a single fertilized egg, genetically the same) and dizygotic twins (fraternal
pairs, developed from separate eggs, 50% alike genetically) are compared.
o When the twins are similar diagnostically, they are said to be concordant.
Concordance for the disorder should be greater in genetically identical
monozygotic pairs than in dizygotic pairs.
o However, not always the case that monozygotic twins are the same in terms
of genetic background! Some studies show that monozygotic twins differ
both genetically and epigenetically in terms of developmental changes in
gene expression.
o Ability to offer a genetic interpretation of data from twin studies hinges on
the equal environment assumption which says that the environmental
factors that are partial causes of concordance are equally influential for
monozygotic pairs and dizygotic pairs.
o Adoptees method study children with abnormal disorders who were adopted
and separated from their parents. This situation has the benefit of
eliminating effects of being raised by disordered parents.
2) Molecular Genetics
o Advanced approach that tries to specify the particular gene or genes involved
and the precise functions of these genes
o An allele is any one of several DNA coding’s that occupy the same position or
location on a chromosome. Genotype is a person’s set of alleles. Genetic
polymorphism is the variability that occurs among members of the species.
o Linkage analysis is a method in molecular genetics used to study people.
They collect diagnostic information and blood samples from affected
individuals and their relatives to study the inheritance pattern of
characteristics whose genetics are fully understood, referred to as genetic
o Gene-environment interactions is the notion that a disorder or symptoms are
the joint product of a genetic vulnerability and specific environmental
experiences or conditions.
3) Genetic Differences Reflected in Temperament
o Temperament is based on notion that individual differences among people
are attributable to genetically predetermined differences that are detectable
as soon as children are born. Temperament are differences in reactivity and
self-regulation (how someone reacts to emotionally upsetting events).
o Three temperament styles: difficult child, easy child, hard-to-warm child
(more reserved)
o Resilient children cope well with adversity, overcontrolled children are overly
inhibited and prone to distress, undercontrolled children are impulsive and
can get out of control (aggressive).

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Neuroscience and Biochemistry in the Nervous System
Each neuron has 4 major parts: cell body, dendrites, one or more axons, terminal
buttons on the 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 electric potential of the cell, travels down the axon to its terminal
Small gap between the terminal ending of the sending axon and cell membrane of
receiving neuron called the synapse
The terminal buttons of each axon contain synaptic vesicles, small structures filled with
neurotransmitters, chemical substances that allow a nerve impulse to cross the synapse.
The cell membrane contains proteins called receptor sites, that allow specific NT to fit
into them, so a message can be sent to the post-synaptic cell.
Excitatory messages lead to creation of nerve impulse in postsynaptic cell, stimulate the
brain. Inhibitory messages make the post-synaptic cell less likely to fire, act as mood
stabilizers or balancers.
Some of the remains in the synapse are broken down by enzymes and some is pumped
back into the presynaptic cell through reuptake.
Norepinephrine, NT of sympathetic nervous system, is involved in producing states of
high arousal and is involved in anxiety disorders. Serotonin is involved in depression
and dopamine in schizophrenia. GABA inhibits some nerve impulses and is involved in
anxiety disorders.
Disorders are usually caused by too much or too little of a particular transmitter.
The Neuroscience of ADHD
Reductions in volume throughout cerebrum and cerebellum in ADHD, delays in cortical
Dopaminergic hypothesis is that ADHD is due to dopamine deficit believed to be genetic
in origin
Three features of ADHD: (1) specific abnormality in reward-related circuitry that leads to
shortened delay gradients, (2) deficits in temporal processing that result in high
intrasubject-intertrial variability, (3) deficits in working memory
Biological Approaches to Treatment
Correct imbalances by providing appropriate doses of the deficient chemical
Deep brain stimulation is treatment of certain disorders and health conditions by
planting battery-operated electrodes in the brain that deliver low-level electrical
Evaluating the Biological Paradigm
Reductionism is the view that whatever is being studied can and should be reduced to
its most basic elements or constituents
2.3 The Cognitive-Behavioural Paradigm
The Behavioural Perspective
The Rise of Behaviourism
Watson introduced behaviourism which is defined as an approach that focuses on
observable behaviour rather than on consciousness (diverged from introspection)
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