Cannabis Flashcards

1
Q

What plant is Cannabis derived from?

A

Hemp - Cannabis Sativa. Also used for rope, cloth and paper and the seeds are used for birdfeed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the psychoactive agent in cannabis?

A

Delta9 Tetrahydocannabinol (THC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is THC concentrated?

A

In the sticky resin secreted by the flowing tops of female plants.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In what three main forms is cannabis obtainable?

A
  • Marijuana (dried and crumbled leaves, smoked)
  • Hashish (solid, prepared from resin, different concentrations)
  • Hash oil (reduced alcoholic extract, single drop placed in joint)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why does the THC content in cannabis vary?

A

Due to sinsemilla - if pollination is prevented it increases potency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In what ways was cannabis first used?

A

2700 BC - Medical use in China
2000 BC - Religious use in India
1000 AD - Hashish use in Arab world

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

When were the Marijuana Tax Act and the first laws legalising medical use?

A

1937 and 1996, respectively.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How was cannabis use introduced into the west?

A

From Egypt by Napoleon’s soldiers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Name two notable ‘hashish eaters’ found by Mareau.

A

Victor Hugo and Alexandre Dumas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Approximately how much cannabis does a typical joint contain?

A

0.5-1g

if THC content 4% = 40mg THC/joint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How is THC absorbed and what percentage of it is absorbed, when smoking a joint?

A

Burning marajuana = vaporisation = absorption = blood plasma

20% of THC absorbed, can be increased by breath holding (Black et al, 1998 7 vs. 15s hold)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

After peak levels of THC in the blood are reached, how do they fall?

A

Through metabolism in liver and fat storage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the half-life of THC, and how long can it be detected in urine for?

A

20-30 hours and 2-3 weeks respectively.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What did Devane et al (1988) do?

A

Identified the cannabinoid receptor (CB1), agonised by THC.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Where are cannabis receptors active?

A

In areas consistent with behavioural effects, e.g. the hippocampus for spatial memory (also substantia nigra and globus padillus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the antagonist for CB1 receptors?

A

SR 141716

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

According to Iversen (2000), what are the acute behavioural effects of cannabis?

A
  • The ‘buzz’ (brief) - light-headedness, dizziness, tingling in extremities due to increased blood flow and HR.
  • The ‘high’ - euphoria, exilharation, disinhibition (the giggles)
  • Being stoned (large amount) - calm, relaxed, dream-like state.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What psychological changes are involved in being ‘stoned’?

A
  • A calm, relaxed, dream-like state.
  • Sensations of floating, enhanced visual and auditory perception
  • Slowing of the perception of time
  • Changes in sociability (increases or decreases)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the physiological effects of cannabis?

A
  • Increased blood flow to skin = warmth
  • Increased HR = pounding pulse sensation
  • The ‘munchies’.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Who has demonstrated the munchies, and what mechanisms is it caused by?

A
  • In humans: Foltin et al (1988), in rats: Williams et al (1998)
  • Caused by increase in palatability (Williams and Kirkham, 2002, rats) and hyperphagia (abolished by CB1 antagonist, Williams & Kirkham, 2002)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What did Heustis et al (2001) find when studying how the effects of marijuana are attenuated by a CB1 antagonist?

A

Had antagonist and placebo group, both given a joint.

In antagonist group, feeling high and stoned was reduced (self-report q.aire), as was HR, but effects weren’t abolished.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What do Heustis et al (2001)’s findings suggest?

A

Either a stronger dose of CB1 antagonist was necessary, or another mechanism mediates effects.

23
Q

What did Agurell et al (1986) find?

A

That route of administration has a substantial effect on blood plasma levels of THC after smoking a joint or oral consumption. (Oral slower to peak but lasted longer).

24
Q

Why do smokers not report a peak until after the joint has been finished?

A
  • Brain and plasma concentrations are not yet at equilibrium

- THC isn’t fully metabolised.

25
Q

What did Curran et al (2002) find about the effects of oral THC consumption on verbal memory?

A

That recall scores decreased with more THC, especially over time.
However according to Hart et al (2001) the effect is attenuated in long term users - cognitive tolerance.

26
Q

What effect does cannabis have on driving?

A

Low doses have relatively few effects.
Moderate or high doses could lead to impaired performance in demanding tasks.
According to Ramaekers et al (2004), it’s a risk factor in car accidents.

27
Q

What have animal studies on SR 141716 found?

A

Richardson et al (1998) - induces hyperalgesia

Black (2004) - decreases food consumption.

28
Q

What have animal studies on the effect of CB1 knockouts (mutant mice) found?

A
  • Varvel and Lichtman (2002) normal acquisition of spatial learning (hidden platforms, then moved), impaired reversal learning.
  • Marsicano et al (2002) normal fear conditioning (Skinner box tone+shock) but impaired extinction.
    = deficit in unlearning?
29
Q

What did Varvel and Lichtman (2002) show in lever-pressing rats?

A

Rats trained to press lever for cocaine, then extenguished and IV THC introduced, increased lever pressing again.
Effect abolished with CB1 antagonist.

30
Q

What did Valjent and Maldonado (2000) find about THC in mice?

A

Conditioned place preference (drug-seeking metaphor) if pre-exposed in home cages.
Experience first aversive then rewarding.

31
Q

At what age are people most likely to initiate marijuana use, according to Brooks et al (1999)?

A

Around 13-22, peaks at 17.

32
Q

About what percentage of people use cannabis in the UK and US?

A

4.6%.

33
Q

According to Gruber and Pope (2002), what are the risk factors for progression from an initial to a regular user?

A
  • Family disturbances
  • Drug use by family/peers
  • School performance
  • Age of onset
34
Q

According to human studies, does tolerance develop with repeated cannabis use?

A
  • Compton et al (1990) = yes

- Kirk & de Wit (1999), Lindgren et al (1981) = no, same high in frequent/infrequent users.

35
Q

What does the slippery slope argument assume about cannabis?

A

That it’s a gateway (natural course) to harder drugs. However this is difficult to assess.

36
Q

According to animal studies, does tolerance develop with repeated cannabis use?

A
  • Breivogel et al (1999) (rats), after daily THC injection for 3 weeks showed progressive reduction in CB1 density and agonist activity, with some brain areas totally desensitised = physiological support.
37
Q

What three things are involved in cannabis dependence?

A
  • Difficulty stopping
  • Craving
  • Withdrawal symptoms
38
Q

What do studies report that cannabis abstinence triggers?

A

Irritability, anxiety, depression, sleep disturbances, aggression, decreased appetite.
Resembles nicotine withdrawal symptoms.

39
Q

How long do cannabis withdrawal symptoms last?

A

Worst in first 2 weeks, can last over a month.

40
Q

What withdrawal effects did early animal studies find?

A

None, but THC has a long half life so is still present in system.

41
Q

What do precipitated withdrawal studies (e.g. Aceto et al (1996)) do?

A

Rats given regular THC injections, then SR 141716.

Display symptoms of hyperactivity (shaking, face rubbing, scratching)

42
Q

What might the findings of precipitated withdrawal studies be due to?

A

Rats being stressed - de Fonseca (1997) found they had high levels of CRH.

43
Q

How is CBT used to treat cannabis dependence?

A

Pts are rewarded with vouchers for providing cannabis-free urine samples.

44
Q

Is CBT for cannabis dependence effective?

A

A little, but significant relapse rate (Moore and Budney, 2003)

45
Q

What did Haney et al (2004) suggest about easing cannabis withdrawal symptoms?

A

Oral consumption of THC.

46
Q

What are the long term psychological effects of chronic cannabis use?

A
  • Decreased education performance

- Cognitive deficits

47
Q

What has research found about the link between chronic cannabis use and school performance?

A
  • Lynsky and Hall (2000) = more negative attitude, poorer grades, absenteeism, linked to amotivational syndrome (apathy, aimlessness, lack of productivity, long term planning and motivation)
  • Fergusson et al (2003) cannabis use predicts poor school performance and drop-out rates.
48
Q

What has research found about the link between chronic cannabis use and cognitive deficits?

A
  • Solowij et al (2002) - deficient 1 and 7 days after exposure in learning, memory and attention.
  • Pope et al (2001) - no difference between heavy users and controls after 28 days = reversible.
49
Q

What are the health effects of chronic cannabis use?

A
  • Not death
  • High levels of tar and carbon monoxide (carcinogens) = cancer
  • Immune system
  • Reproductive function
50
Q

What has research found on the effects of chronic cannabis use on the immune system?

A

Cabreal & Pettit (1998) - THC suppresses immune function, increased risk of viral and bacterial infection.

51
Q

What has research found on the effects of chronic cannabis use on reproductive function?

A

In women - suppresses luteinising hormone release (but can be tolerated)

In men - Smith & Asch (1987) = decreased sperm count, but only in heavy users.

52
Q

What are the clinical applications of cannabis?

A
  • Synthetic compounds (dronabinol=antiemetic for chemo patients, nabilone=appetite stimulant for AIDS patients).
  • Chronic pain treatment (MS, spinal cord injury, glaucoma)
  • Limited widespread use due to side effects and that it’s more effective when smoked.
53
Q

What is HU-221?

A

A cannabinoid that doesn’t activate CB1 receptors and therefore has no side effects - undergoing clinical trials.