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C83MLP Mechanisms of Learning and Psychopathology. Lecture 2: Psychological side effects of cancer treatment. Dr. Mark Haselgrove. Assessment:. (1) Dissertation (50%) 4000 words max. Titles assigned 13 th March 2013 Dissertation tutorials in small (N≈6) groups with MH/TB/CB/JR - PowerPoint PPT Presentation
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Lecture 2:
Psychological side effects of cancer treatment
C83MLP Mechanisms of Learning and Psychopathology
Dr. Mark Haselgrove
Assessment:
(1) Dissertation (50%) 4000 words max
- Titles assigned 13th March 2013- Dissertation tutorials in small (N≈6) groups with MH/TB/CB/JR before and after Easter- Hand in by Tues 7th May 2013
(1) Examination (50%) May/June 2013
- Two Sections: (A) Content by JR/CB (B) Content by MH/TB- 4 questions in each section. YOU ANSWER ONE FROM EACH.- 2 hours long
All past papers for C83MLP now on Moodle
Content of Lecture
(2) Taste aversion learning
(3) Anorexia – Acquired food aversions
(1) What are the Psychological side effects?
- Is it a CR?
- Prospective studies
(5) Treatments for side effects
(4) Anticipatory Nausea and Vomiting
- The scapegoat effect
- Susceptibility to ANV
- Other treatments
What are the psychological side effects?
(1) Anorexia
- Reduced appetite, refusal of food- Particularly to protein rich (e.g. meat) food
(2) Anticipatory Nausea and Vomiting (ANV)
- Nausea (with or without vomiting) occurring during the hrs before scheduled drug infusions- Particularly when in (or thinking about) infusion setting
Possible sources of gastric distress in cancer patients:
- Tumour growth
- Radiotherapy
- Chemotherapy (CT)
Taste aversion learningAnimal is made ill after consuming a particular food
Food Lithium Chloride Injection
Animal subsequently avoids that food – Aversion developed
- Successful in only 1 trial
- Conditioning effective despite Intervals of several hrs between food and illness
Smith & Roll (1968)
Anorexia
Bernstein (1991)
Could be the result of learned aversions to specific foods that wereeaten during the period of tumour (or radiotherapy) induced nausea
Most patients learn aversions to numerous tastes, so anorexia appears general
Midkiff & Bernstein (1985)
- Questionnaire results suggest CT induced aversions more likely to:
- Eggs, Cheese Meat (high protein – stronger flavours)- Less likely to carbohydrates (weaker flavours)
- More likely to develop to novel foods
- More likely to develop to food eaten just before CT session
Discussion point:Why would these
variables affect food aversions?
Anorexia (Cont.)
Bernstein & Borson (1986)
- Evidence that rats learn aversion to specific novel foods during:Period of tumour, orRadiotherapy induced nausea
- Rescorla (1968) Contingency is important for learning…!
Discussion point:Aversion develops even though
nausea is extended in time, why?
Anticipatory Nausea & Vomiting
- Nausea (with or without vomiting) occurring during the hrs before scheduled drug infusions- Particularly when in (or thinking about) infusion setting
Morrow & Dobkin (1988); Carey & Burish (1988)
- Occurs in 20%-40% of CT patients (more with the most emetic drugs)- Not helped by antiemetic medication – A substantial clinical problem
i.e.
Is ANV a classically conditioned response?
Stimuli during/preceding infusion
Nausea/vomiting which follows infusion
CS US/UR
Anticipatory Nausea & Vomiting
Can nausea be conditioned to contextual cues?
e.g. Garcia & Koelling (1966) - Flavour → Illness
Light → Shock
Flavour →Shock
Light → Illness
Easy to Learn
Hard to Learn
Hall & Symonds (2006)
Context A → IllnessContext B → nothing
Sucrose in A: 12 mlSucrose in B: 16 ml
Alternative Hypothesis: It’s an anxiety symptom. But, its hardly found with other forms of cancer treatment (e.g. bone marrow aspiration – severe anticipatory anxiety, no nausea vomiting)
Anticipatory Nausea & Vomiting
Retrospective studies have shown ANV associated with:
- But, some effects could be artifacts. (e.g. (3), strong emetic drugs could “mark” ANV/PNV
-Thus prospective studies are needed to allow effects of variables to be dissociated
(1) Increasing number of infusions(2) The severity of post nausea and vomiting (PNV)(3) Younger patients (who get strongly emetic drugs)
- All consistent with conditioning (see also Bovbjerg, 2006)
Anticipatory Nausea & Vomiting
Andrykowski et al (1985)
If ANV is classically conditioned, predict increased incidence of ANV with(1) more severe PNV (greater US intensity)(2) Longer duration of infusion (longer CS-US pairing)(3) Higher pre-infusion state anxiety (greater conditionability)
80 adult patients starting first CT treatment. 71 completed study (mean 10 infusions)
Measures: Before each treatment: Spielberger trait anxiety, EPI extraversionBefore each infusion
(a) rated PNV severity after last infusion(b) Anxiety now and over past 24 hrs(c) Physical symptoms (e.g. vomiting [now and over 24 hrs])
Duration of 1st and 2nd infusionAge, drug, infusion technique, type of cancer.
Anticipatory Nausea & Vomiting
Andrykowski et al (1985) cont..
Results 26/71 (37%) showed ANV, No association with type of drug,technique, diagnosis, but all who showed PNV also reported ANV
Analysis of predictors – Multiple regression. DV = Did person ever show ANV (Yes/No)
Predictors: (1) Severity of PNV after infusion 1(2) Mean duration of infusions 1 and 2(3) State anxiety pre infusion 1 and 2(4) trait anxiety, extraversion, age
Anticipatory Nausea & Vomiting
Andrykowski et al (1985) still cont..
(“Hierarchical regression” tests whether a variable predicts difference in ANV after prediction by other variables has been accounted for)
F = Does this variable significantly predict whogets ANV?
Simple r = correlation between ANV and variable
Discussion point:Does this support a
conditioning account of ANV?
Anticipatory Nausea & Vomiting
Kvale & Hugdahl (1994) – ANV and Autonomic conditionability
If ANV is classically conditioned, then it should co-vary with individual differences known to affect classical conditioning
Looked at heart rate (HR) conditioning (like nausea, this is controlled by parasympathetic ANS)
2 CSs, 6 s tones (1200 and 2000 Hz. US = 1 s white noise burst)
CS+ → NoiseCS- → No Noise
Ss had to press button when they heard noiseHR recorded 3 s pre and 10s post both CSs
RTs to Noise US – ANV group faster than n-ANV group
Discussion point:Is this really
conditioning?
Anticipatory Nausea & Vomiting
Can a CR be learned to an arbitrary stimulus which precedes CT infusions
Bovbjerg et al (1992) – Conditioned taste aversion induced by CT
78 (47) women receiving CT for breast cancer – 8 infusions, over 3/4 week intervals.Informed that this was a study of CT side effects, no mention of taste aversion.
Exp Group: 150 ml lemon-lime drink in distinctive cup before infusion (N=25)Control Group: not offered lemon-lime drink (N=22)
Results: Exp grp often refused drink in clinic - Tested at home soon after (as were controls)
Exp Group Control Group
Nausea pre drink post drinkRating of drink(1= good, 9= bad)
4186.5
53.54.8
Exp grp: aversion to drink correlated with PNV only after 1st infusion
Of those who reported PNV after infusion 1: 8/14 developed aversion.
Of those who didn’t, 0/9 developed aversion
Potential treatments
Andresen et al (1990) – The scapegoat effect
Suggested novel tasting food eaten after “normal” food which precedes CT willacquire strong association and overshadow association to normal food (act as a scapegoat)
25 adult CT patients. Infusions received either 1/week to 1 every 6 weeks
Either a novel or a familiar food consumed 10-15 min before CT session
Hedonic rating scale used to asses preference for regular foods. (1 = dislike, 9 = like)
Novel group Familiar group
N increase in hedonic ratingN decrease in hedonic ratingN No change
221120
112422
Potential treatments
Klosterhalfen et al (2005) – Latent inhibition of ANV
Motion Sickness susceptibility questionnaire
7 item scale, Ss rated:
- Vertigo- Headache- Nausea- Urge to vomit- Tiredness- Sweating- Stomach awareness
Potential treatments
Carey & Burish (1988); Morrow & Dobkin (1988)
Types of treatment that have been reported:
Hypnosis to minimise PNV Relaxation & guided imagery during infusion
Systematic desensitizationVideo game play during infusion
Discussion point:How might these work
(in terms of conditioning)?
Possible mechanisms…
Nonspecific/placebo effectCounter-conditioningDiversion of attention
Further reading…