Lecture 2:
- The role of Paradigms: A set of basic assumptions a clinician will make. A general perspective
that defines how to conceptualize, study a subject, patient, how to gather and interpret data
and how to think about the subject.
- Ex: psychiatrist believes in medication alters neurochemistry to alter behaviour (their
paradigm= a biological approach)
- Ex: Psychotherapist psychogenic original beliefs to problems
- 4 main paradigms:
1. Biological Paradigm:
Medical model
Mental disorders arise due to some neurobiological antecedent
Behavioural genetics: study of individual difference in behaviour that are attributable to
differences in genetic makeup.
o Some sort of clue if a disease/ illness has a genetic component to it.
o Genotype vs. Phenotype
Genotype: inherited and unobservable. Get it from biological parents
Phenotype: Observable behavioural characteristics product of genotype
and environmental factors (ex: anxiety level in person)
A disorder is not inherited genetically. Can have the genetics that leave you pre-disposed to
presenting w/ the phenotypes of this disorder (schizophrenia, anxiety, depression) but not
inherited.
One disorder that is inherited= Huntington’s disease
o Know this b/c we use diff study methods. There are 4 methods:
1) Family Method
2) Twin Method
a. Monozygotic twins (MZ Twins) 100% identical twins
b. Dizygotic twins (DZ) 00> 50% identical
3) Adoptees method
4) Linkage Analysis
Family Method:
-If pre-disposition for a mental disorder can be inherited, study of family relationship should show
relationship b/w # of shared genes in index case (person w/ disorder) & prevalence of disorder in
probands (relatives)
st
- Ex: individual w. schizophrenia, learned from family method that if you are 1 degree relative, then
10% likelihood more of getting schizophrenia (norm pop 1% chance of getting it)
- 1 degree relatives examples siblings/ parents (10%)
Twin Method: - Twin set, both have schizophrenia, known as concordance (similar diagnostically speaking)
- Monozygotic twins (if they show a higher concordance level than dizygotic twins, then genetic
obviously genetic component plays a role) strong argument that characteristic is heritable
Adoptee Method:
- Twins grow up in an environment away from biological family (may rule out environmental
factors) ex: if twins have schizophrenic mom and grow up w. adoptive parents and b/come
schizo then envio of mom being schizo didn’t play a role.
Linkage Analysis:
- Look for a large collection of individuals w/in a family unit who might have a disorder (looking
for biological or genetic markers) blood samples, urine samples etc. Try to see if anything is
common
- Neurotransmission & reuptake = key terms
o Neurotransmission: molecules that move from 1 neuron to the next= neurotransmitters
(transmitters detected that carry messages about pain, pleasure, anxiety etc)
o Reuptake refers to process in the brain of neurons trying to retrieve chemicals that were
not received by the next neuron.
Structure & function of the human brain
Cortical Brain structure impt higher order cognition (outer structure-frontal lobes,
parietal lobes, occipital lobes, temporal lobes)
Sub-cortical lobes movement (inner structure- hippocampus, pituitary etc).
Frontal Lobes executive functioning (motor movement, planning, inhabitation, emotion)
o Right-frontal lobe when lesioned can give rise to manic episode
o Left- depressed like state (apathy) lack of motivation
o Right- retrieval (exam time) & speech (broca’s area)
o Left- encoding (trying to absorb info entering brain –lec time)
Temporal lobe language centre
o Wernicke’s area (left side) -> comprehension of verbal
o Right-side comprehension of non-verbal (train coming…move)
o Hippocampus -> consolidates information (Stamps info by solidifying it—allows for
later retrieval)
Steps:
1) Encoding
2) Consolodation (hippocampus) -> Alzhimers disease, hippo affected)
3) Retrieval
Ppl w/ sizeures report hallucination (diff types of neuro imaging techniques, see problems
with temporal lobes)
Parietal Lobes touch (visual-spatial)
o Left- difficulty understanding movement (ex: person told to brush teeth but combs
hair instead) o Right- visual-spatial neglect (ignores left side, ex: plate of food but only eats right
side)
Occipital Lobes vision
Ways to investigate the brain when looking for these types of lesions (neuro-imaging
instrumentation)
1) Structural imaging techniques (CT scans or MRI)
2) Functional neuro-imaging techniques (SPECT) & (PET)
a. Looks at blood moving through the brain
o Best of both worlds = Fmri (Structural functional)
Biological Paradigm approaches to treatment: psychoactive drugs
Anxiolytics used for anxiety but also for sleep disorders, phobias, and pain disorders
o Benzodiazepines
Antipsychotics schizophrenia, behavioural disorders (severe brain injuries), dementia, pp;
w/ degenerative conditions, sometimes also depression
Psycho-stimulants ADHD, improves cognition, Alzheimers, dementia, cognitive disorders.
Different categories of drugs but psychiatrists use shotgun approach (may use drug b/c
known to help w/ disorder or use multiple drugs until
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