Substance use and Addiction Flashcards
What are categories of drugs?
- Depressant
- Stimulant
- Hallucinogenic
- Cannabinoid
What is experimental/recreational use?
causing no/limited difficulties
majority of population
What are positive reinforcement for drugs?
- escapism
- Get high
- Like it
- stay awake
What are negative reinforcement for drugs?
- boredom
- get to sleep
- reduce anxiety
- feel better
Why do you need to know why someone takes drugs?
-informs treatment
-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
Eg depression, anxiety, liver problems, high blood pressure, aggression
What is the process of using drugs?
Like, want to need and then regular sue (harmful) when period of loss, grieve, pandemic
What is 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)
e.g. common chest cough if smoker or got in fight form drinking
What is hazardous substance abuse?
likely to cause harm if continues at this level)
What is the need criteria?
spiralling dependence
What happens in the like want need process?
neuroadaptions
What is the ICD-10 diagnostic criteria foe dependence syndrome?
- a strong desire or sense of compulsion to take the substance
- difficulties in 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
- 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
What is 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 gertrelief from it or ‘treat’ it
What is the prevalence of alcohol dependence?
–595, 000 estimated prevalence
–103,471 in treatment
-~82% of adults in need of specialist treatment for alcohol not receiving it
What is the impact of COVID-19 on alcohol dependence?
Over 8.4 million people are now (September) drinking at higher risk, up from 4.8 million in February
What is the prevalence of 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
What is the impact of Covid-19 on opiate dependence?
3,459 new adult cases in April 2020 - up 20% from 2,947 in April 2019 - the highest numbers in April since 2015
What is important to see for drugs and alcohol?
harm to others and harm to users (alcohol most harm to others as violence)
What is addiction?
compulsive drug use despite harmful consequences, characterized by an inability to stop using a drug; failure to meet work, social, or family obligations; and, (depending on the drug) tolerance and withdrawal
What dependence?
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
-Not seeking etc or taking more than prescription
Why is the way people use the words addiction of dependence important?
- When people use the term “dependence,” they are usually referring to a physical dependence on a substance
- Dependence is characterized by the symptoms of tolerance and withdrawal
- While it is possible to have a physical dependence without being addicted, addiction is usually right around the corner.
- Part of the reason for the change was the confusion surrounding the word ‘dependence.’
- The hope is that defining an addiction as a substance use disorder was a more inclusive way to identify people who need help, but may not have a debilitating addiction.
What is gambling disorder?
-Behavioural addiction
•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.
What is internet gaming disorder?
-Behavioural addiction
•added to ICD-11 under addictive disorders
•in the DSM-5 is under “Conditions for Further Study
Why do people want to speed up brain entry?
more “rush” more addiction
What are the elements involved in alcohol/drug use and addiction?
- Social, environmental factors
- Personal factors eg genetic, personality traits
- Drug factors
How does the brain work from use to addiction?
- Pre-existing vulnerability (e.g. family history / age)
- Drug exposure (compensatory neuroadaptions to maintain brain function / resilience)
- Recovery: sustained or cycles of remission and relapse
Are the exposure become chronic what does your brain do?
neuroadaptions
What happens the earlier you use drugs?
more likely to be dependent
Why do people drink?
- Get sleep
- reduce anxiety
- Then get tolerant so carry on to avoid withdrawal
What excitatory system does alcohol affect?
- Glutamate system
- NMDA receptor
What inhibitory system does alcohol affect?
- GABA-benzodiazepine (GABA-A) system
- GABA receptor
What happens to the excitatory system with acute alcohol?
- blocked
- Impaired memory (alcoholic blackouts)
What happens to the inhbiotyr system with acute alcohol?
- boosted
- anxiolysis
- sedation
What happens with chronic alcohol exposure that results in neuroadaptations so that GABA and glutamate remain in balance in presence of alcohol?
- Upregulation of excitatory system
2. Reduced function in inhibitory system - tolerance
How does the GABA receptor respond to chronic alcohol neuroadaption?
Switch in subunits to make less sensitive to alcohol
What happens in the withdrawal state?
Chronic alcohol exposure results in neuroadaptations: in absence of alcohol GABA & glutamate are no longer in balance
Why do you need to treat in alcohol withdrawal? How do you treat?
- Upregulation of excitatory system means that NMDA receptor:increase in Ca2+
- toxic leading to hyperexcitability (seizures) and cell death (atrophy) - Treat with benzodiazepines to boost GABA function
What are some other treatments for alcohol withdrawal?
- Inpatients
- Treated with lorazepam / diazepam (benzodiazepines)
- MRS on d1 (EW)
–Increased glutamate
•MRS on d14 (SA)
–Glutamate levels reduced closer to healthy controls (HC)
What can help people remain abstinent?
- Acamprostate
- Reduction in MRS glutamate in acamprosate treated group - potentially neuroprotective
What are some models of addiction?
- Reward deficiency (positive reinforcement)
- Impulsivity / compulsivity
- Overcoming adverse state e.g. withdrawal, anxiety (negative reinforcement)
What do rewards lead to?
Increase levels of dopamine in ventral striatum
What sort of system is the dopamine pathway?
‘pleasure-reward-motivation’
What is a modulator of dopamine system?
-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
What state is addiction thought to be?
‘reward deficient’ state
How does substance abuse affect dopamine system?
- Dopamine released and cocaine, amphetamine block reuptake, so lots of dopamine in synapse
- Amphetamine enhances release of dopamine - directly target dopamine synapse
- Other drugs of abuse eg alcohol, opiates, nicotine increase dopamine neuron firing in ventral tenemental area - indirect effect.
What may predispose people to drugs?
low levels of D2 receptors predispose subjects to use drugs, as high levels of D2 did not like the feeling of stimulant
What is activated in the anticipation of winning?
ventral striatum
What could cause people to use drugs in future?
had blunted reward to getting money years before - reward system not working as well
When is there a blunted reward system?
- Abstinent addicts compared with controls
- In absitent addicts those with blunted response to anticipation of reward are more likely to relapse which is consistent with ‘reward deficiency’ theories of addiction
- So maybe if can reverse blunted reward system less likely to relapse
Is it a given to have a blunted reward system?
no
What areas of the brain involved in addiction?
- binge/intoxication
- withdrawal/negative affect
- preoccupation/anticipation /craving
What are of the brain is involved in withdrawal/negative affect?
amygdala
What happens as addiction/dependence develops?
change from positive to negative reinforcement
How does this change happen?
- Get drug, positive effect and then negative withdrawal but over time neuroadpatation, high gets less, but withdrawal gets greater
- Positive reinforcement goes and so carry on taking to avoid negative so negative reinforcement, so fearful if not drug.
What happens to the reward system with withdrawal and negative emotional states in addiction?
reduced dopamine and mu opoid function
What happens to the stress system with withdrawal and negative emotional states in addiction?
increased activity in many including kappa opioid (dynorphin), noradrenaline (arousal system) CRF (stress) etc
What happens to the amygdala with withdrawal and negative emotional states in addiction?
Dysregulation
What happens to amygdala when shown adverse and normal image?
Not heightened in normal picture with normal volunteers but normal. picture heightened for abstinent polydrug users (not for alcoholics)
What does change from voluntary drug use to more habitual and compulsive drug use involve?
-transition from:
•prefrontal to striatal control over drug taking (i.e. prefrontal ‘top-down’ control is diminished with greater striatal reward drive
•overt time go from ventral (limbic or emotional) to dorsal (habit) striatum.
-Role for ‘memory’ (eg hippocampus) in craving
How do you asses neurocircuitry in inhibitory control with fMRI?
go-nogo task
What happens in the go-nogo task?
- Lights up putamen (dorsal striatum) and inferior frontal gyrus
- Alocholics more activity in frontal cortex - longer absence the greater activity so greater activity during inhibitory control may facilitate in staying sober
- Polydrug less likely to stay absence
What was the result like for abstinent alcoholics in go-nogo task?
- Greater response in frontal pole/inferior frontal gyrus during inhibiting response in abstinent alcoholics
- Greater response associated with longer abstinence
