Week 6 & 7 - Substance Use Disorder (SUD) Flashcards
Define SUD
SUD is where an indiviual uses substances in behaviour that becomes compulsive + they continue despite harmful consequences
- SUD causes a psyhcological + physical change in brain (from repeated exposure)
- its a treatable condition + recovery is possible
- use ICD-11 to diagnose disorder
- use DSM-5
- liekly to have some form of SUD if some criteria is met (not all)
Why does SUD occur
SUD caused by many factors e.g. genetic, social, environmental
- social ~ experiences with friends, to have fun
- environmental ~ help you fell better, alleivate stress, anxiety, fear etc.
- genetic ~ genes associated with alcohol breakdown
What symptoms are associated with SUD
- Euphoria (intesnse pleasurable feeling)
- feeling differs depending on type of drug, route (oral or IV)
- IV adminstration = feeling more intense as enters bloodstream then brain quicker
- High
- Buzz
- Period of sedation (drowsiness, relaxed)
Explain the role of the reward pathway (dopamine pathway)
Mesolimbic Pathway
- When take substance binds to receptors on dopamine cell bodies (in VTA) = cell bodies activated
- ↑ Dopamine relased into nucleus accumbens
- Release of dopamine drives pleasurable feeling
- Nucleus accumebns interacts with diff. area e.g. pre-frontal cortex, areas linked to forming memories (associated with substance), decisions, emotions etc.
NOTE: some substances may:
- act at synapse = prevents re-uptake of dopamine
- act at GABA receptors = removes inhibiton of dopamine neurones = ↑ dopamine released
- as GABA neurones feed onto dopamine neurones
List the substances that can cause addiction
- Alcohol
- Nicotine
- Drugs e.g. weed, cocaine
- Psychiatric meds i.e. benzodiazepines
- Caffeine
- Food
- Gambling
- Sex
- Harmful relationships
- Technology i.e. phone, devices
Anything that gives pleasure + is done excessively
How do changes in the brain occur during addiction
Neuroadaptation occurs
- Formation of drug related memories (hippocampus)
- causes cravings - Changes in VTA and nucleus accumbens (NA) after long-term exposure to drug
- Decision-making process is impaired = impulsivity = seek drug (due to frontol cortex changes)
- Amygdala is altered ~ relates to stress + craving
- part of brain that processes emotionaal response - Dissociation of dopamine circuits (after repeated exposure)
- mesolimbic (VTA to NA)
- nigrostriatal = get changes in behaviour
- ↓ activation of D2 recptors + ↑ activation of D1 and D3
List the 3 different stages of the addiction cycle
- Take drug
- could be inital (1st time) or continuous - Experience WITHDRAWALS
- once drug has left system
- experience low mood, physical effects
- if 1st time effects wont be as significant - Begin CRAVING drug
- feel anticipation to take drug again
- feel preoccupied
- leads to taking drug = stage 1 = leading to dependance
NOTE: don’t become addicted after first time
Explain the addiction cycle after inital (1st time) use
- TAKE drug
- gives a pleasurable feeling due to surge of D2 release into nucleus accumbens (NA)
- higher surge = more intense feeling
- Experience WITHDRAWAL
- effects begin to wear off as D2 levels decrease
- may get dip in D2 levels (below normal) = experience low moods
- Begin CRAVING drug
- become preoccupied with the intense feeling = want to do it again
- stronger the D2 dip is = stonger craving
Explain the addiction cycle after continued / repeated use
- TAKE drug MORE FREQUENTLY
- due to pleasurable feeling it gave BUT more drug is required to give effect the intial use gave (tolerance building)
- Experience WITHDRAWAL
- more often you take it = more likely to get withdrawal as becoming dependat on it - Stronger CRAVINGS
- may even feel anticipation when in environemnt usuallyy take drugs in
- happens sevral times a day
How does drug tolerance occur
- over time pharmcological effect of drug ↓ (NOT immediate)
- When tolerance begins = will need to take more of drug to feel same effects
MECHANISM:
1. Desensitisation of receptor occurs
- i.e. receptor becomes less responsive / no response to drug
- Fast change: conformational change occurs with receptor when drug binds BUT ligand channel doesnt open
- Slow change: intracellular regions of the receptor become phosphorylated leading to desensitisation (of ligand receptor) OR second messengers cant be activated (G-protein receptor)
- Translocation (movement) of receptor
- in substance misuse endocytosis of functional receptors (on membrane) occurs at greater rate = ↓ no. of receptors
- Mediators are used up
- substance prevents reuptake of monamines (MA) like dopamine = MA not recycled
- MA stores become depleted - Drug metabolised more quicker
- need to take more of substance to have the same effect
- as now when take same amount will have a ↓ plasma conc.
Whats the difference between physcial and psychological dependance
Physical:
- get physical symptoms when stop taking substance (withdrawal)
- can last for days, weeks or longer (depends on drug, length of use, severity)
Psychological:
- drive to take substance again to get pleasurable feeling / avoid withdrawal effects (craving)
Both are linked + have role in addiction cycle
What are the specifc symptoms for AUD addiction
AUD - Alcohol Use Disorder | Initial and withdrawal symp.
INITIAL:
- Self-control impaired
- Sedation, sleepy (seen in mild intoxication)
- Memory and judgement affected
- Acute alcohol posioning if consume ↑ amount
- Binge drinking
- Chronic relapse i.e. occurs over long period of time
WITHDRAWAL:
- ↑ heart rate, BP
- tremor
- ↑ sweating
- anxiety + agitation
- due to nueroadaptations in stress system
- delirium tremens (DTs) and seizures
- = have high levels of alcohol
- may have hallucinations
The CIWA-m Score for Alcohol Withdrawal
Points awarded for:
- N&V
- Agitation
- Anxiety
- Tremors
- Sweating
- Auditory disturbances
- Visual disturbances
- Tactile disturbaces
- e.g. itching, pins & needles, burning, tingling etc,
- Headache
- Disorientation
- ↑ RR, HR, BP
SCORES:
- ≤ 8 = does not require medication for withdrawal
WITHIN First 24hrs (monitor 1hr)
- < 10 = no treatment / monitor
- 10 to 21 = 30mg Chlordiazepoxide
- >21 = 40mg Chlordiazepoxide
AFTER 24hrs (monitor every 2hrs)
- <16 = no treatment
- 16 to 21 = 20mg Chlordiazepoxide
- >21= 30mg Chlordiazepoxide
How does Ethanol (Alcohol) cause addiction
NOTE: most addictive substance: cheap, easily accessible, legal, social
Ethanol interacts with ligand and voltage -gated ion channels
- mainly NMDA and GABA A receptors
- more alcohol consumed = more changes in receptor
- changes in how alcohol is metabolised
Need to maintain alcohol intake to prevent withdrawal (i.e. hangover)
CAUSES:
- Upregulation of NMDA receptor
- Change in GABA A sub-units = functionality ↓ = need ↑ alcohol to have good effects
- ↑ excitation when GABA inhibition is lost
What is the 1st line for AUD
- Offer psyhchological intervention e.g. CBT
- If refuse pschological / not responsive or want meds. then use pharmacological
