Cannabis

Question 1

background

Answer 1

• cannabis sativa
• psychoactive agent - tetrahydrocannabinol
• sticky resin in flower of females

Question 2

farms

Answer 2

• marijuana - dried and crumbled THC
• sinsemilla - increase potency
• hashish - prepared from resin
• hash oil - reduced alcoholic extract

Question 3

pharmacology

Answer 3

THC content
- typical joint - 0.5-1g
- average 15% in 1995 and 2015
Smoking
burning - vaporisation of THC absorbed into blood and plasma
absorption increased by holding breathe
- half life of 20-30 hours - metabolism in liver

Question 4

administration effects

Answer 4

Agurell et al
route has substantial effect blood plasma THC level after smoking vs consumption
- ingestion > metabolism in liver
- effect is sustained due to slow metabolism

Question 5

cannabinoid receptor

Answer 5

Devane et al
receptor = CB1
agonist = THC
antagonist = SR141716
consistent with behavioural effects

Question 6

antagonist effect

Answer 6

Huestis et al
- attenuated by treatment of CB1 antagonist
- placebo vs antagonist
- rating of effect and heat rate measured

Question 7

endocannabinoid system

Answer 7

Richardson et al
- effects of CB1 antagonist
- hyperalgesia - increase pain sensitivity
- endocannabinoids decrease responsiveness to pain

Question 8

acute behavioural and physiological effects

Answer 8

Iversen: the buzz, the high, being stoned
increased blood flow, heart rate and hunger
Foltin et al
hyperphagia induced by THC
palatability increase in rats

Question 9

rewarding effects

Answer 9

Tanda et al
- intravenous - lever press
- extinguished
- intravenous THC - lever press
- abolished with CB1 antagonist
- intravenous THC - lever press

Question 10

conditioned place preference

Answer 10

Valjent and Maldonado
- conditioned place preference with THC in mice
- pre exposed in home cages
- first experience = aversive then rewarding

Question 11

effects of CB1 knockout

Answer 11

Vavel and Lichtman
- normal acquisition of spatial learning
- impaired reversal learning
Morsicano et al
- normal fear conditioning
- impaired extinction
- deficit in new learning

Question 12

cognitive deficits

Answer 12

• oral THC impairs verbal memory
• psychomotor failure
• dose dependent
• task dependent

Question 13

age of initiation

Answer 13

• widely used, 4.6% in UK and US
• peaks at 17 years old

Question 14

gateway drug

Answer 14

family/ peer influence
age of onset

Question 15

tolerance

Answer 15

Compton et al
tolerance after administration of marijuana or THC
same high in all users

Question 16

animal studies consistent

Answer 16

Breivagel et al: rats
daily injections of THC for 3 weeks
reduction in receptor density and activity
brain areas desensitised

no effect of withdrawal but long half life
precipitate withdrawal
- rats given THC injections twice daily
- then antagonist
- hyperactivity
de Fonseca
stressed increased corticotrophin

Question 17

dependence

Answer 17

Budney et al
abstinence triggers withdrawal
resemble nicotine withdrawal
worst in first 2 weeks

Question 18

treatment

Answer 18

CBT
- relapse
- withdrawal eased with THC
- difficult in long term

behavioural
- associated with poor education, negative attitudes, poor grades, absenteeism
- amotivational syndrome: apathy
- drop out rates

Question 19

cognitive effects

Answer 19

cognitive deficits
- standardised learning, memory, attention tests
- deficits after 1 and 7 days
- only linked to recent use - no difference after
- 28 abstinence

Question 20

health

Answer 20

• carcinogens, tar, CO
• cardiovascular
• THC suppresses immune function and increase infection
• reduce reproductive function

Question 21

clinical applications

Answer 21

• C19, C20 - extracts in medication
• dronabinol - chemotherapy
• nabilone - appetite stimulant for AIDS
  chronic pain
  HU-211 doesn’t activate CB1 - no side effects, clinical trials