Marijuana

Question 1

What is hemp?

Answer 1

Cannabis sativa; not psychoactive but illegal to grow in fear you can hide marijuana in it

Question 2

What is marijuana?

Answer 2

Dried preparation from the flowering hemp

Cannabinoids are highly concentrated high up flowering tops of female plant buds

When cannabis isn’t pollinated, resin containin buds are produced in the final attempt to pollinate

Trichromes produce resins which is what contains the THC

Question 3

What are other cannabis derivatives?

Answer 3

Hashish-dried resin from top of female trichromes - known as kief and pressed into blocks

Hash oil = solvent extraction from hashish (high in THC)

Question 4

What are the routes of administration for marijuana?

Answer 4

Smoking - typically in cigarettes - 20-40% THC absorbed

Vaporization - Inhalation of vapour

Eating - slow but strong effect

Question 5

What is the legalisation and decriminalisation of marijuana?

Answer 5

Now legal in 14 states, decriminalised in 16

Question 6

What are the uses for medical marijuana?

Answer 6

Not widely accepted but can treat;

Glaucoma
Antiemetic (reduces nausea)
Anticonvulsant
Appetite enhancer
Analgesic

Question 7

What are the cannabinoid receptors?

Answer 7

CB1: in the brain; presynaptic terminals in basal ganglia, hippo and cerebellum

CB2: found in immune system and glia

Question 8

What are the cannabinoid pharmacokinetics?

Answer 8

Cannabinoids are highly lipid soluble therefore THC reaches the brain quickly

Is distributed to body fat stores

THC (partial cannbinoid agonist) is metabolised in the liver - produces active metabolite

Question 9

What are the behavioural effects of cannabis?

Answer 9

Dose dependent effects

Buzz: slightly lightheaded, tingling feeling

High: euphoria and exhilaration

Stoned: floating sensations, slowing of time, enhanced visual and auditory perceptions

Question 10

What are the physiological effects of cannabis?

Answer 10

Red eyes, increased heart rate, blood flow to skin and appetite stimulation

Question 11

What are the undesirable effects of cannabis?

Answer 11

Psychotic symptoms, anxiety, impaired judgement, reaction times, motor impairment, memory impairment

Question 12

THC in experimental animals (reviewed by Panagis et al., 2008)

Answer 12

Is readily discriminated as different to other drug classes

Enhances DA release

At low dose is produces CPP and self-administration

Aversion at high doses

Question 13

How is the CB1R involved in reward?

Answer 13

Rimonabant decreases self-administration of THC and other drugs

CB1 knockout mice seem generally less sensitive to rewards

Question 14

How are synthetic cannabinoids different to THC?

Answer 14

WIN55212 is a full agonist at CB1 and CB2 and is reliably self-administered (Lecca et al, 2006)

Rimonabant (antagonist/CB1 inverse agonist) reduces subjective effects of marijuana

Question 15

What are the endocannabinoids?

Answer 15

Anandamide: partial agonist

2-AG: full agonist

Question 16

What are the functions of endocannabinoids?

Answer 16

Regulators of synaptic transmission for both glutamate and GABA

Play an important role in hunger, feeding and social play

Question 17

How does tolerance affect marijuana?

Answer 17

Mixed evidence for the ‘high’ tolerance

Question 18

What are effects of heavy/repeated cannabis use?

Answer 18

Various effects on executive functions

Withdrawal symptoms include irritability, anxiety, decreased appetite etc

Dependence risk of 9-10%

Question 19

Is there a link between cannabis and psychosis?

Answer 19

Modest risk factor of 6-8%

HOWEVER: Degenhardt et al. (2003) argue cannabis use has increased but psychosis has not