What does cannabis make you eat

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What does cannabis make you eat?

• Amanda Townson
• PhD Supervisor Prof. Tim Kirkham
• University of Liverpool

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Overview

• Background
• Research questions
• Study
• Next Steps

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Background - History

• Cannabis
• 10,000 year history of cultivation
• 5,000 year documented history of consumption
• Western medicine (OShaughnessy, 1842)
• Wonder drug for all ailments!
• Superseded by specific medications
• Fell into disuse by 1932
• Now government backed research

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Why does cannabis affect us?

• Exogenous cannabinoids e.g. THC discovered
• (Gaoni Mechoulam, 1964, Mechoulam et al., 1970)
• Central peripheral receptors isolated
• (Onaivi et al., 1996 and Breivogel Childers,
  1998)
• Anandamide (from Sanskrit Ananda, inner bliss)
  endocannabinoid discovered
• (Devane et al., 1992)

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Human munchies

• Early accounts of increased appetite
• American servicemen in Panama (Siler et al.,
  1933)
• Cannabis cigarettes, of unknown potency
• New York inmates (Allentuck Bowman, 1942)
• 0.4 to 0.8gm of cannabis cigarettes pills
• particularly sweets
• Cannabis users survey (Tart, 1970)
• Taste sensations take on new qualities
• I enjoy eating very much and eating a lot
• If I try to imagine what something tastes like,
  I can do so very vividly
• I crave sweet things to eat, like chocolate,
  more than other foods.

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Healthy Volunteer Studies 1

• Early studies used unrealistic foods smoking
• Cannabis cigarettes
• Unknown THC content
• 50 vs 4 marshmallows! (Abel, 1971)
• Increased no. of daily snacks
• Increased daily calorie intake from sweet, solid
  snack foods
• Increased body weight over residential period
  (Foltin et al., 1986- 1.84 THC 1988 - 2.3
  THC )
• Oral THC
• 0.5mg THC per kg, average dose 32mg (range 27mg -
  39mg)
• increased chocolate milkshake consumption, hunger
  ratings and decreased satiation (Hollister, 1971)

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Healthy Volunteer Studies 2

• More recent studies
• Single Dose Smoked vs Oral THC
• 1.8 or 3.1 THC cigarettes q.i.d
• Increased eating occasions hunger ratings which
  didnt diminish over residential period
• Tolerance to subjective ratings but not to
  increased food intake
• (Haney et al. 1999)
• Repeated Dose Smoked vs Oral THC
• 2x 1g cannabis cigarettes (containing 3.1 THC)
  q.i.d. or THC 20mg q.i.d.
• Both increased food intake (oral significantly)
• Both increased no. of meals/ eating occasions by
  approx 3 per day (Hart et al. 2002)

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Patient Populations

• Increases appetite
• Cancer patients (Regelson et al., 1976), HIV
  patients (Plasse et al., 1991), AIDS patients
  (Beal et al., 1995)
• Antiemetic (anti sickness) effect may affect
  appetite? (Gralla, 1999)
• HIV patients (Plasse et al., 1991), AIDS patients
  (Beal et al., 1995)
• Attenuates weight loss
• Single case cancer patient (Sacks et al., 1990),
  HIV wasting syndrome (Plasse et al., 1991), AIDS
  patients (Beal et al., 1995)

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Patient Populations

• Significant weight gain
• Cancer patients (Regelson et al., 1976), HIV
  patients (Plasse et al., 1991), Dementia patients
  (Volicer et al., 1997)
• Increased body fat
• AIDS patients (Struwe et al., 1993)
• Elevated mood
• AIDS patients (Struwe et al., 1993 and Beal et
  al., 1995)

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Animal models tell us

• cannabinoid effects mediated by cannabinoid
  receptors in the brain
• THC mimics the actions of endocannabinoids
• incentive value of food is increased
• THC activates endogenous opioid system that
  mediates food palatability

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Problems with human studies

• Varying
• doses
• dosing schedules
• methods of administration
• health problems associated with smoking cannabis
• cannabis experience in participants
• e.g. heavy marijuana users used without washout
  period so baseline abstinence period

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Problems with human studies

• Varying
• social contact
• food preferences (not accounted for)
• foods provided
• food availability
• health
• etc!

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Some arising research questions

• What is the dose response?
• What is the drug time course?
• Which foods are eaten more?
• Is mood involved?
• Could this be used therapeutically in the elderly
  or recuperating?

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Study Set Up Organisations/ individuals liased
with
Data Protection Officer
West Berkshire Local Research Ethics Committee
Medicines Healthcare products Regulatory Agency
(MHRA)
Pathology Laboratory RBBH
Researcher
Safety Office
GW
CRI
University Departments/ Individuals
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Experiment outline

• Acute (one day, 09.00 16.00), randomised,
  double blind study
• 4 conditions placebo, 2.5mg, 5.0mg 7.5mg THC
• Single THC dose administered via mouth spray in
  the morning post baseline measures (blood
  pressure monitored)
• Participants tested individually

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Experiment measures

• Visual analogue scale (VAS) assessed mood
  appetite with masking questions (e.g. how dizzy
  do you feel?)
• Food intake observed via video for snacks meal
  consumed over test day number of items, weight,
  calorific value
• Distractor psychological tests
• short term memory forward backwards digit
  span
• working memory Operation Span (OSPAN) Tower
  of Hanoi
• visio spatial memory tasks Jos game
• Designed to measure eating naturally

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Food provided

• Snacks freely available all day
• Fruit
• red green apples Granny Smiths Empire
• bananas
• Sweet snacks
• fun size chocolate Bounty, Maltesers, Mars Bar,
  Milky Way, Snickers Twix
• fun size sweets Skittles Starburst
• biscuits - digestives
• Savoury snacks
• Crisps Cheese Onion, Ready Salted Salt
  Vinegar

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Food provided

• Cold lunch available 3 hours post baseline for 3
  hours
• Sandwiches
• cheese salad ham salad on brown white bread

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Health screening pre study abstinence

• Participants screened for health
• health questionnaire
• blood test
• pregnancy
• food allergies
• Participants abstained from
• alcohol from midnight
• cannabis for one week
• all recreational drugs for two weeks
• and extreme exercise the day before the study

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Pre study baseline measures

• Baseline measures gathered
• cannabis, smoking alcohol use
• eating norms, food preferences, eating behaviour
  (DEBQ)
• BMI, whether on a diet, fasted/ non fasted,
  menstrual cycle
• medication/ supplements taken

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Participants N 39, f 31, m 8BMI normal
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Participant Course
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Dose response - calories

• Placebo comparisons
• 4.95mg THC sig. increases calorie intake
  plt0.01
• 7.5mg THC increases calorie intake ns

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4.95mg THC - Which foods increased the calories ?

• Chocolate plt0.05
• Sandwiches plt0.05
• Especially cheese sandwiches plt0.05

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4.95mg THC - Which foods increased the calories ?
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Drug time course - Hunger

• 2 hours ( 1 3 hours)
• 4.95mg THC sig. more hungry at 2 hrs

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Drug time course - Hunger
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Is mood involved?

• No!

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Side effects Placebo 4.95mg THC
Placebo no. of side effects reported 8/12
67 4.95mg THC no. of side effects reported
12/17 71
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Conclusions

• 4.95mg THC is the most effective dose to increase
  calorie intake (plt0.01).
• Increased calories come from Chocolate plt0.05,
  Sandwiches plt0.05 particularly Cheese
  Sandwiches plt0.05.
• 2 hour drug time course for hunger.
• 2 hours after dosing the 4.95mg THC significantly
  increases hunger ratings.
• Mood doesnt seem to be involved in THC induced
  hyperphagia.

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Next steps

• Finish analysing wealth of data collected
• Publish findings submit PhD
• Continue with post doctoral research to answer
  outstanding questions

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Future research questions

• What is the most effective dosing schedule?
• Do foods or some foods become more palatable?
• Do taste thresholds change?

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Acknowledgements

• Dr John Wright - Clinical Research Unit, School
  of Food Biosciences, University of Reading
• Dr Sonia Tucci - University of Liverpool/ Reading
• Jan Luff, Steve Hicks, Rafe Bundy - Hugh Sinclair
  Nutrition Unit, School of Food Biosciences,
  University of Reading
• Dr Paul Robinson - Biochemistry, Royal Berkshire
  Hospital
• Heather House - GW Pharmaceuticals, Salisbury.
• Martin Yeomans Department of Psychology,
  University of Sussex
• Dr Phil Beaman Jo Smith School of Psychology,
  University of Reading
• Masterfoods Slough.

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The End

• Thank you