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pyb260 > WEEK 3 - research methods > Flashcards

WEEK 3 - research methods Flashcards

1
Q

What is the Independent variables (IV)

A
  • Variable that is manipulated in a study
  • E.g., amount of drug administered/ type of drug administered
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2
Q

What is the Dependent variables

A
  • Variable that is measured in a study (to observe effect of IV)
  • E.g., behaviour/mood/cognition/motor performance
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3
Q

What is a between-subject designs (independent groups)

A
  • Experiments are conducted with 2 (or more) different
    groups
  • (IV is operationalised as different groups)
  • E.g., Group A given a new drug; Group B given CBT
  • Usually interested in the difference between the means of
    these groups.
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4
Q

What are the advantages of a between subject design?

A
  • Easier & more time efficient to run
  • Allows observation of variables that are not stable (i.e., habituation, practice effects, etc.)
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5
Q

What are the disadvantages of a between subject design?

A
  • Many variables are unable to be controlled (e.g., systematic
    differences between the groups)
    –> need more participants so these effects average out
  • Results are presented in terms of group differences; masks changes within the individual
  • Method of allocating to groups (randomised controlled trial; consecutive case design?)
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6
Q

What is a Within-subject designs (repeated measures)?

A
  • Same participants involved in every level of the experiment
  • IV is operationalised as different levels/testing occasions that all participant receive
  • E.g., same participants are tested for attention span before
    & after taking a drug
  • Usually interested in difference in the mean of the 2(+)
    testing occasions
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7
Q

What are the advantages of Within-subject design?

A
  • Requires fewer participants
  • Each participant acts as their own control
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8
Q

What are the disadvantages of a Within-subject design?

A
  • Not amenable to measurement of unstable variables
  • Time & money
  • May need alternate forms to assess DV to counteract practice effects
  • May need to counteract cross-over effects (Landauer, 1975)
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9
Q

WHat are Control groups/conditions

A
  • Used to ensure the effect observed is due to the variable wemanipulated & not some other variable
  • Especially important in between-subject designs
  • A control group will be identical to the groups being tested, except for the manipulation

For example:
Group A: has depression & given new antidepressant (exp. group)
Group B: has depression but receives no treatment (control group) - participants with same symptoms/severity, demographics etc. as experimental group

  • If no difference is observed between the 2 groups, then it appears the new antidepressant did not work
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10
Q

What are Placebo controls

A
  • sometimes in drug research a placebo condition will be used
  • A placebo control condition will be similar to the experimental condition, except rather than receiving the drug (or no drug) they receive a substance containing no active ingredients (a placebo)

E.g., Group A: has depression, receives new antidepressant
Group B: has depression, & receives sugar pill

  • Placebo controls are extremely useful for investigating whether any benefits derived from a drug are due to placebo effects
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11
Q

What are Three-groups designs

A

3 groups may be used
1. Given a new drug
2. Given a proven drug
3. Given a placebo

  • Allows comparison between new drug & placebo
  • Allows comparison between new & established drugs
  • Allows experimenter to see if measures are sensitive enough to detect change (i.e., compare proven drug & placebo)
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12
Q

What are specificity of drug effects:

A
  • e.g., include groups comprising people with different mental illnesses → does the drug work in depression exclusively?
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13
Q

What is longitudinal design

A

ffects may also be assessed over time (multiple measurements)

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14
Q

What is cross-sectional design

A

once of design

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15
Q

What is bias

A
  • Bias results in systematic errors in measurement or prediction
  • Bias can enter an experiment from many different sources
  • Experimenter & participant expectations/bias (double blind
    studies)
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16
Q

WHat are selction biases

A
  • Demographic differences (age/gender)
  • Cultural differences
  • Personality differences
  • Education etc. etc. etc
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17
Q

Rate which forms of study has the most control (1) to least control (7)

A
  1. experiment
  2. correlation
  3. Test
  4. survey
  5. case history
  6. Naturalistic observation
  7. Introspection
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18
Q

What are Ethical & legal constraints on drug research

A

In most drug studies there are severe ethical & legal constraints
* E.g., alcohol studies: legal constraints are relatively few (except min. age), but there are still ethical problems (e.g., how do people get home after experiment?)

  • administering alcohol (& other legal drugs) to participants to participants can be costly (time & money)
  • retrospective consumption questionnaires are often used (or daily consumption questions (diaries))
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19
Q

What are the potential varibles or domains we look for effects in during drug research?

A

changes to
* Arousal
* Cognition
* Perception
* Motor function
* Mood
* We might also want to measure side effects / biochemical or physiological drug effects

20
Q

How/why do we measure perfomrence within a drug test

A
  • The more measures we use:
  • the more comprehensive our assessment
  • the more costly our experiment (financial & time)
  • the greater the need to consider experimental controls &
    logistics (e.g., order we administer measures).
  • Assessing change/differences in performance across performance domains (e.g., arousal, cognition, perception, motor function) tells us something about how the drug works, & the effects it produces (primary & side effects)
21
Q

Measuring arousal

A
  • Arousal level changes naturally throughout the day, but can also be affected by a number of things – including drug use
  • Most drugs are thought of as either ‘ stimulants’ or ‘depressants’, when given in large doses (at low doses this categorization does not hold)
  • ‘uppers’ & ‘downers’ imply a relationship between arousal & mood
    – not necessarily that clear
  • High arousal does not high activity
22
Q

How is arousal measured?

A
  • Since various drugs have an effect on arousal how we measure arousal is important
  • Electroencephalograph (EEG): a measure of arousal/ detects potential differences between points on the scalp & neutral points on the body
  • Other ways to measure arousal:
  • Introspection?
  • Unstructured Introspection
  • Systematic Introspection – e.g., self-report scales (e.g., VAS)
  • Ask an observer?
23
Q

What are the levels of arsoual

A

Death
Coma
Sleep
Drowsy
Normal
Aroused
Highly excited
Mania
Convulsions
Death

24
Q

Measuring mood

A
  • Drugs can impact significantly on mood
  • Can be studied experimentally (e.g., we can test drug effects by inducing mood states) or using a between-groups design (e.g., depressed vs. non- depressed patients)
  • Measurements could be by self-report, doctor’s assessment, informant report, questionnaire, tests of biological markers of depression etc.
  • Consider the advantages & disadvantages of these ways of
    assessing drug effects on mood
25
Q

Measuring perception

A
  • Refers to the detection & integration of external stimuli
  • Visual & auditory perception are most often studied
  • Perception research often investigates the changes in the sensitivity of a person’s perception brought about by changes in the internal or external environment (e.g., drug use)
  • These changes in sensitivity = thresholds (two types)
  • Absolute Threshold –> Lowest value of stimulus detectable by an organ (e.g., eyes)
  • Difference Thresholds –> Organ detects a change in level of stimulation
26
Q

What are absoloute thresholds?

A

The lowest value of a stimulus that can be
accurately detected 50% of the time. Example:

  • Vision: candle flame on a dark, straight road, at 60km
  • Smell: 1 drop of perfume in a 6-room apartment
  • Hearing: watch tick 6 m away
  • Taste: 1 tsp sugar in 8 L water
  • Touch: wing of a fly falling on your cheek from 1cm
27
Q

What is difference thresholds?

A
  • measure the ability of an individual to detect a
    change in a stimulus
  • E.g., when can you tell the light is brighter than it was before?
  • Critical frequency at fusion (CFF) – sensitive to drug effects
28
Q

Measuring cognitive performance

A
  • Ability to process, store & retrieve information (e.g., attention, memory, learning, etc.); can also include higher-level processes such as planning, set-shifting & response inhibition
  • Often manipulated experimentally
    –> Effect of drug at different stages of cognitive process can be assessed (e.g., may affect storage of information, or earlier attention processes)
29
Q

Measuring motor performance

A
  • Drugs can have a significant impact on motor tasks like coordination (e.g., alcohol)
  • How might we measure these?
  • ? simple or choice reaction time, tapping, pursuit rotor, etc.
30
Q

Measuring side effects/physiological effects

A

Some methods of assessing side effects:
* Questionnaire (e.g., yes/no questions; rating scale etc.)
* Biochemical assay
* Doctor’s check-up/ physical examination
* Informant report
* Strengths & weaknesses of these methods

Some methods of assessing physiological effects: biochemical assays, MRI scans, PET scans

31
Q

How do you identify a good research design?

A

What is the research question: does the chosen design allow that question to be answered?

  • What are the strengths & limitations of the measures used to assess effects?
    –> How sensitive/ appropriate are the measures?
    –> How precisely can measurements be made?
  • What experimental controls have been put in place?
  • Effect size: how meaningful is the change observed in terms ofeveryday functioning?
32
Q

What are some special factors to consider with drug studies when trying to identify a good research design?

A
  • Washout effects (esp. in w/g designs)
  • Deprivation study designs (withdrawal)
  • Level of drug administered
  • Dose of drug used (e.g., compliance with instructions)
  • Inclusion of biochemical assays
  • Controls for routine / habitual or other drug use
  • Non-specific treatment effects
  • Special group selection factors (mild, moderate, & severe
    depression?)
  • Timeframe for assessing effect
  • Reporting of adverse events/non-compliance / attrition
  • If in-vitro cellular trials are used: how generalizable are results to intact living systems?
  • If animal trials are used: how similar is the species, apparatus, domain of function being tested?
33
Q

What are the Major considerations in drug development?

A
  1. Medical need
  2. Commercial potential
  3. Feasibility for mass production
  • “Orphan drugs”
34
Q

What is the FDA approval processes: 4 stages

A
  1. Preclinical investigation (basic science; tests on cells &
    animals; effects of drugs noted for side effects, toxic effects,
    addictions, cancerous tumors, fetal deformities,
    pharmacodynamics)
  2. Clinical investigation (human testing, 4 phases, incl. 3 phases of clinical trials)
  3. Review of NDA (New Drug Application)
  4. Postmarketing studies
35
Q

What are some Specific limitations of animal studies,

A
  • Cats: markedly different sleep-wake cycles (e.g., sleep 65-80% of the time)
  • Monkeys: develop obvious behavioural abnormalities from
    confinement
  • Rabbits: different enzymes from humans (e.g., can eat some plants that would be poisonous to humans)

Despite limitations, animals studies generally provide a valid
indication of the likely drug effect in humans

36
Q

In the drug development & animal testing (Stage
1:step 1) what is the first step of the process

A

Step 1. Determining toxicity
* Acute toxicity (for single doses)
* Subacute toxicity (short term use of drug)
* Chronic toxicity (longer-term drug use)
* Special toxicity (carcinogenic? teratogenic?)

37
Q

In the drug development & animal testing (Stage
1:step 2) what is the second step of the process

A

Step 2. Pharmacological studies (direct & indirect)

  • Direct:
    – to locate direct measures of changes induced by drugs via tools such as:
  • rating scales, objective measures (e.g., “jiggle-cage”/ “tail
    suspension test”), conditioning studies (see next slides), sites- of-action studies
  • Indirect:
  • to identify markers or signs of effects rather than evidence of the effect itself or - to observe effects on behaviours that are induced in animals
38
Q

What are the general principles of Direct pharmacological studies- conditioning

A
  • Stimulant substances: rapid learning/acquisition of conditioned response, poor discrimination / ready generalisation, slow termination/extinction
  • Depressant substance: slow acquisition/learning, poor
    generalisation/easy discrimination, rapid extinction
39
Q

Measuring conditioned behavior in nonhuman (what are the Schedules of Reinforcement)

A
  • Schedules of Reinforcement: pattern that determines when
    reinforcements are to be given
  • Ratio Schedules
  • Fixed ratio (FR)
  • Variable ratio (VR)
  • Interval Schedules
  • Fixed Interval (FI)
  • Variable Interval (VI)
  • Avoidance-Escape Task
  • Punishment
  • Stimulus Properties of Drugs
  • stimulus properties
  • ability to act as a discriminative stimulus in a discrimination learning task.
40
Q

Measuring conditioned behavior in nonhuman (what are the Reinforcing properties of drugs)

A
  • Rate of Responding
  • Progressive Ratio
  • Breaking point (organism will stop responding)
  • Choice
  • 2 levers; one has consequences. Exposure to 2 drugs over
    separate sessions; then observe animal’s choice of drug A or B.
  • Conditioned Place Preference
  • Animal will spend time in area of reinforcement
41
Q

FDA approval processes

A
  • Stage 1 Pre-clinical (animal studies to determine suitability as therapeutic agent; measurement of ED50 , LD50 & therapeutic index) – i.e., toxicity & pharmacological studies
  • Stage 2 Clinical investigation (human volunteers):
  • Phase 1: Pharmacokinetic & Safety Testing - human testing to determine toxicity & side effects in healthy human (paid) volunteers
  • Phase 2: Small-scale Effectiveness Testing - human testing in clinical samples (i.e., patient groups) to assess potential therapeutic effects (+adverse)
  • Phase 3: Large-scale Effectiveness Testing - expanded clinical trials using basic 3-group design
    –> approval or rejection of new drug for licensing & marketing
  • Phase 4: accumulation of data on drug effects
42
Q

In the Phases of human testing (clinical trials) what is phase one?

A
  • Phase 1
  • 20-100 healthy volunteers
  • Informed consent mandatory
  • evaluate side effects
  • establish final, correct dosage
  • pharmacokinetics studied
  • generally takes 2 years
43
Q

In the Phases of human testing (clinical trials) what is phase two?

A

Phase 2
* 100-300 patients who have disease drug intended to treat
* drug given on experimental basis
* determines therapeutic effect
* usually takes 2 years

44
Q

In the Phases of human testing (clinical trials) what is phase three?

A

Phase 3
* 1000-3000 ill patient volunteers
* administered same way that it will be used on the market
* performance vs. other drugs currently on the market (3-group design with placebo; single or double-blind)
* usually lasts 2-4 years

Completion of Phase 3
* drug company submits all documentation to FDA in a New Drug Application (NDA)
* waits for final FDA decision → approval or denial
* only 20% NDAs receive final FDA approval for marketing

45
Q

In the Phases of human testing (clinical trials) what is phase four? (postmarking study)

A
  • After NDA review completed & approved
  • Lasts on average, 15 years
  • New drug placed on the market
  • Surveillance: check for new harmful effects in larger group of humans
  • Drug removed from market if serious problems occur

pyb260 (5 decks)

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