Substance use addictions Flashcards
(29 cards)
what are some examples of substances that can be abused?
actual drug may not be integral, it is more how it is used
Alcohol
Nicotine
Cannabis
Stimulants: Amphetamine Cocaine Crack Ecstasy
Opioids (prescribed, OTC):
Heroin, fentanyl
DF118
Ketamine
Solvents
GHB, GBL
Benzodiazepines
Psychedelics:
LSD, Magic mushrooms
Nitrous oxide
Khat
‘Novel psychoactive substances’: ~950 synthetic (UNODC); new: ~1/wk Categories: Depressant, stimulant, hallucinogenic. cannabinoid
what does experimental/recreational use mean?
causing no/limited difficulties
majority of population
what is a possible definition of substance abuse?
A pattern of substance use that has caused damage to a person’s physical or mental health or has resulted in behaviour leading to harm to the health of others
why might people take recreational drugs (split into categories)?
positive reinforcement: (gain positive state) escape get high they like it stay awake
negative reinforcement: (overcome adverse state) boredom reduce anxiety to get sleep to feel better
rebel
fit in
why not?
everyone does
why is it important to ask why people do drugs?
then you can start to understand why and formulate a plan to address it.
what is the course of alcohol/ drug use to abuse?
Experimental/‘recreational’ use,
causes no/limited difficulties
(majority of population)
first they would “like” a drink ->
then they “want” a drink ->
then they “need” a drink ->
Increasingly regular use
(fewer people)
harmful
this first step is reversible, so intervention should be done here
this goes along with increasing problems
lastly they will spiral, “needing” it
this is dependance
this last step is one way. once you are dependant it is ver very hard to go back
what is the definition of harmful substance use?
Actual damage should have been caused to the mental or physical health of the user in the absence of diagnosis of dependence syndrome.
(as a Dr, the fact that they are seeing you may mean that many people will fulfill criteria for this diagnosis)
(Hazardous use – likely to cause harm if continues at this level - one step before harmful)
what is the definition of dependance syndrome (diagnostic criteria) (6 points)?
- a strong desire or sense of compulsion to take the substance
- DIFFICULTIES ON CONTROLLING substance taking behaviour in terms of its onset, termination, or levels of use
who has control, you or ‘the drug/behaviour’?
when did you last have a drink/drug? - a physiological withdrawal state when substance use has stopped or been reduced
- a ‘negative’ state (from uncomfortable to intolerable) so user takes drug/alcohol to get relief from it or ‘treat’ it - evidence of tolerance: need to take more to get same effect
- progressive neglect of alternative interests
- persisting with substance use despite clear evidence of overtly harmful consequences
have to meet 3 of these in the last 12 months
what is the epidemiology of alcohol dependance?
Alcohol dependence :
595, 000 estimated prevalence
103,471 in treatment
~82% of adults in need of specialist treatment for alcohol not receiving it.
Impact of Covid 2020:
Over 8.4 million people are now (September) drinking at higher risk, up from 4.8 million in February
what is the epidemiology of opiate dependance?
Opiate dependence:
257,476 estimated prevalence.
170,032 in treatment
~46% of adults in need of specialist treatment for opiates not receiving it.
Death rates rising from opiates and from cocaine
Impact of Covid 2020:
3,459 new adult cases in April 2020 - up 20% from 2,947 in April 2019 - the highest numbers
which drugs are most and least harmful?
most: alcohol heroin crack cocaine meth
least: mushrooms LSD ecstacy anabolic steroids
what is the difference between addiction and dependance?
addiction:
compulsive drug use despite harmful consequences, characterised by an inability to stop using a drug; failure to meet work, social, or family obligations; and, (depending on the drug) tolerance and withdrawal.
dependance:
In biology/pharmacology, dependence refers to a physical adaptation to a substance
Tolerance/withdrawal
Eg opioid, benzodiazepine, alcohol
So can be dependent and not addicted
these are used pretty interchangeably, but are not the same
you have to be precise
especially in GP referrals etc
what are some behavioural addictions?
Gambling disorder:
Many similarities in aetiology, neurobiology and treatment approaches, as well as comorbidity, with substance dependence
Reclassified as behavioural addiction in DSM-5/ICD-11 from an ‘impulse control disorder’ previously
Internet gaming disorder :
added to ICD-11 under addictive disorders
in the DSM-5 is under “Conditions for Further Study”
why is entry of drugs sped up?
Faster brain entry –> more “rush” and more addiction
opium -> morphine -> heroin -> snorted heroin -> IV heroin
coca leaves -> coca paste -> cocaine -> crack
chewing tobacco -> snuff -> cigarettes
what factors are involved in drug/alcohol use and addiction?
Social (eg. pub nights, or smoking together),
environmental factors
Personal factors eg genetic, personality traits
Drug factors
how does the brain change from use to addiction?
pre existing vulnerability:
family history
age (young more vulnerable)
->
drug exposure: Compensatory neuroadaptations to maintain brain function
resilience/tolerance (have to do more to get the same effect)
withdrawal
->
recovery: sustained or Cycles of remission and relapse
what does alcohol do in the brain acutely?
Alcohol alters the balance between brain’s inhibitory and excitatory system
Excitatory system: Glutamate system
NMDA receptors
Inhibitory system
GABA-benzodiazepine (GABA-A) system:
GABA-A receptor
it blocks the excitatory system (leads to impaired memory)
and boosts the inhibitory system (anxiolysis, sedation)
what does alcohol do to the brain chronically?
Chronic alcohol exposure results in neuroadaptations so that GABA & glutamate remain in balance in presence of alcohol:
doesnt have to be drinking very much
tolerance:
reduced function of inhibitory system
GABA-A receptor - switch in types to make it less sensitive to alcohol
upregulation of the excitatory system
what does absence of alcohol do to the brain after chronic exposure?
Chronic alcohol exposure results in neuroadaptations: in absence of alcohol GABA & glutamate are no longer in balance – withdrawal state:
still reduced function in inhibitory system
really high upregulation of the excitatory system
NMDA receptor:increase in Ca2+
- toxic leading to hyperexcitability (seizures) and cell death (atrophy)
how is alcohol withdrawal treated?
Treat with benzodiazepines to boost GABA function
what are the 3 models of addiction?
Reward deficiency (positive reinforcement)
Overcoming adverse state eg withdrawal, anxiety (negative reinforcement
Impulsivity/ compulsivity
how is dopamine related to addiction?
Natural rewards such as food, sex increase levels of a chemical – dopamine - in a part of the brain called ventral striatum.
Drugs of abuse also increase levels of dopamine here.
This dopamine pathway has been referred to as the ‘pleasure-reward-motivation’ system it tarts being the part that motivates you to get more of that drug
addiction has been conceptualized as
a ‘reward deficient’ state
- so people take drugs to overcome this
A key modulator is opioid system – particularly mu opioid that mediates pleasurable effects (eg of alcohol, ‘endorphin ‘rush’); others include GABA-B, cannabinoids, glutamate etc that are targets for treatment
how do substances of abuse interact with the dopamine system?
dopamine is released from the presynaptic neurone
it binds to receptors on the post synaptic neurone
the dopamine is taken back up into the presynaptic neurone
substances of abuse (eg. cocaine and amphetamine) prevent this reuptake
(they are dopamine transporter reuptake blockers)
so there is a lot more dopamine present in the synapse and a lot more of a signal produced
(direct effect)
amphetamine also increases the release of dopamine from the presynaptic neurone
(direct effect)
other drugs of abuse (alcohol, opiates, nicotine) increase dopamine neurone firing in VTA (indirectly)
how do we assess function of the reward system (dopamine)?
fMRI
(not PRT coz it is quite expensive and involves radiation)
using “winning money”
as an incentive
this will make the reward centres light up
