cannabis Flashcards
what is the main psychoactive agent
tetrahydocannabinol
what is cannabis produced from
the weedlike plant - cannabis sativa
when were the first state laws legalising medical use
1996
what are the 4 forms of cannabis
- marijuana - dried leaves
- sinsemilla
- hashish - solid
- hash oil - single drop placed in joint
what is the THC content in a joint
- a typical joint contains approximately 0.5-1g of cannabis
- a joint with 1g of cannabis, 4% THC content, contains 40mg of THC
- average of 15% in 2015
what is the process of smoking cannabis
- burning marijuana results in vaporisation of THC
- THC readily absorbed through the lungs into blood plasma
how much THC is absorbed into the lungs
20%
what did Black et al 1998 find about the absorption of THC
can be increased with breath holding
- more when held for 15s vs 7s
what is the half life of THC
20-30 hours
what are the effects of THC through oral consumption
- slower delayed effects relative to smoking because smoking bypasses liver metabolism - straight from lungs to blood plasma
- effect is more sustained due to slower metabolism and absorption into blood plasma
what is the cannabis receptor
CB1
what is the cannabis agonist
THC
what is the cannabis antagonist
SR141716
where are cannabis receptors found
- globus pallidus
- substantia nigra
- hippocampus
where are CB2 receptors found
- immune cells and less prevalent in the brain
what did Huestis et al 2001 find about antagonist effects
- effects of marijuana attenuated by treatment of CB1 antagonist
- two groups - placebo and SR141716 group
- responses recorded over an hour
- less effect with antagonist
what did richardson et al 1988 find about the effects of CB1 antagonist
it induces hyperalgesia - pain sensitivity
what did varvel and lichtman find were effects of CB1 knockout
- normal acquisition of spatial learning
- impaired reversal learning
what did Marsicano et al 2002 find about effects of CB1 knockout
- normal fear conditioning
- impaired extinction
- a deficit in unlearning/new learning
what are the behavioural effects of cannabis according to Iversen 2000
- the buzz - light headedness, dizziness, tingling
- the high - euphoria, exhilaration, disinhibition
- being stoned - calm and relaxed, floating
what are the physiological effects of cannabis
- increased blood flow
- increased heart rate
- increased hunger
- hyperphagia
what is hyperphagia
increased appetite and consumption
how is hyperphagia induced and abolished
- induced by THC
- abolished by CB1 antagonist
what increases in rats in response to THC
palatability
what did Curran et al 2002 find about cognitive deficits
oral THC administration impairs verbal memory
- psychomotor functions affected
what did Hart et al 2001 find about cognitive deficits
- cognitive tolerance in heavy users
what is dose dependent in cognitive deficits
- low doses have relatively few effects - especially in heavy users
what is task dependent in cognitive deficits
- if task demands are high there is impaired performance
what did Tanda et al find about the rewarding effects of cannabinoids
- research on mice
- phase 0 - intravenous cocaine - lever press
- phase 1 - extinguished with saline
- phase 2 - intravenous THC - lever press
- phase 3 - effect abolished with CB1 antagonist
- phase 4 - intravenous THC - lever press
what did Valjent and Maldonado 2000 find about conditioned place preference
- conditioned place preference with THC mice
- only works if mice pre-exposed to THC in home cages
- first experience is aversive and then rewarding
according to Brooks et al 1999 what is the age of initial use
17
according to Gruber and Pope 2002 what are the risk factors of cannabis
family disturbances, drug use by family or peers, school performance, age of onset
what does tolerance mean
needing a greater does to achieve the same effect
what does dependence mean
- difficulty stopping taking cannabis
- craving for cannabis
- withdrawal symptoms
what did compton et al 1990 find about tolerance
tolerance observed following repeated administration of marijuana or pure THC
what did Kirk and de Wit 1999, Lindgren et al 1981 find about tolerance
same ‘high’ in light/frequent users relative to heavy/frequent users
what did budney et al 2003 nand kouri et al 1999 find about dependence
- abstinence triggers irritability, anxiety, depression, sleep disturbance, aggressiveness, decrease appetite
- resemble nicotine withdrawal symptoms
- worst in first 2 weeks - can last for over a month
what did early animal studies find about drug withdrawal
- no effect of drug withdrawal
- but THC has a long half life, thus may still be present in system
what did Aceto et al 1996 find about precipitated withdrawal
- rats given twice daily THC injections
- then given SR 141716
- symptoms of hyperactivity
how is CBT used for treatment of cannabis use disorder
Participants rewarded with vouchers for
providing cannabis-free urine samples
is CBT effective in treating cannabis use disorder
- useful in the short-term but difficult to achieve long term abstinence
what did Lynsky and Hall 2000 find about behavioural effects of cannabis use
Chronic cannabis use associated with poor education performance
- More negative attitudes about school
- Poorer grades
- Increased absenteeism
what is amotivational syndrome
- apathy, aimlessness, lack of productivity, long term planning and motivation
what did Fergusson et al 2003 find about regular cannabis use
- regular cannabis use in early life predicts poor school performance and drop-out rates
what are the cognitive effects of cannabis use
- Cognitive deficits in long term users (Solowij et al. 2002)
- Standardised tests of learning, memory and attention
- long-term user deficient 1 and 7 days after exposure
No difference between heavy users and controls after 28 days of abstinence (Pope et al., 2001)
Cognitive deficits linked to recent use – reversible over time.
what health issues can cannabis lead to
- cardiovascular disorders
- cerebrovascular disorders
what did Cabreal and Pettit 1998 find about cannabis and the immune system
- THC suppresses immune function
- increases risk of viral and bacterial infection
what did Smith and Asch 1987 find about reproductive function and cannabis
- smoking in women suppresses luteinizing hormone release
- reduced sperm count in men but only in heavy users
what is dronabinol
cannabis is used as antiemetic for chemotherapy patients
what is nabilone
cannabis is used as an appetite stimulant on AIDS patients
what chronic pain can cannabis be used to treat
- multiple sclerosis
- spinal cord injury
- glaucoma
what are the main sources of caffiene
- coffee
- tea
- chocolate
- energy and carbonated drinks
how many people consume caffeine regularly
80-90%
what is the average daily intake of caffeine for an adult
200-400mg
how much caffeine is in one cup of coffee
80-100mg
how does caffeine process through our body
- absorbed through the gastrointestinal tract in about 30-60 mins
- plasma half life about 4 hours but usually topped up - rising blood plasma throughout the day
- caffeine is converted to metabolites by the liver
- 95% is excreted in urine, 2-5% in faeces, rest through saliva
- caffeine acts primarily by blocking adenosine receptors in the brain
what are the behavioural effects of caffeine in rats
- biphasic effect
- low does - stimulant
- high does - reversal
what are the positive effects of low to intermediate doses of caffeine - smith et al
- increased alertness
- reduced tension
- reduced reaction time
what did Grgic et al 2018 find about behavioural effects of caffeine
- modest but significant benefits to muscle strength, power and indurance
what did Elhaj et al 2021 find about behavioural effects of caffeine
- mechanism of positive effect on sport is still under investigation; could be mediated by effects of alertness and reduced muscle tension, placebo effect
what are negative behavioural effects of caffeine
- disruption to sleep - particularly in older adults - clark et al 2017
- when consumed within 6 hours of going to sleep - Drake et al 2013
what are the negative effects of higher doses of caffeine
- tension
- jitteriness
- anxiety
- panic disorder patients may be hypersensitive leading to panic attacks
what did Griffiths and Mumford 1995 find about tolerance of caffeine
- heavy drinkers can consume coffee before bed
what did Griffiths et al 1990 find about withdrawal symptoms of caffeine
- headache, drowsiness, fatigue, impaired concentration and psychomotor performance
- withdrawal effects last a few days of consecutive abstinence but will dissipate
what did Nehlig 2016v find about health effects of caffeine
little to no risk to healthy, non-pregnant adults
what are the acute consumption effects of caffeine for non consumers
- increase blood pressure
- increase respiratory rate
- increase water excretion
what are the risks to pregnancy from caffeine
- associated with infant birth weight
- dose-dependant increase in risk of still births - greenwood
- prenatal exposure is associated with developmental effects such as childhood obesity
