Flashcards in Substance Misuse Deck (61)
What is harmful use?
A pattern of use likely to cause physical or psychological damage
What is dependency?
A cluster of physiological, behavioural and cognitive symptoms in which use of a substance takes on a much higher priority than other behaviours that once had grater value
What is withdrawal?
A transient state occurring while readjusting to lower levels of the drug in the body
What is the classical conditioning theory of dependence?
Cravings become conditioned to cues
So that a cue itself can trigger a craving and thus cause drug seeking behaviour
What is the operant conditioning theory of dependence?
Behaviours rewarded are repeated: positive reinforcement
Behaviours are repeated if they relieve unpleasant experiences: negative reinforcement
What are features of dependence?
Problems controlling use
Continued use despite harm
Reinstatement following abstinence
Narrowing of the repertoire
What is tolerance?
Larger doses required to gain the same effect experienced previously
What is compulsion?
Strong desire to use the substance
What is salience?
Obtaining and using the substance becomes so important that other interests are neglected
What is narrowing the repertoire?
Loss of variation in use of the substance?
What is the social learning theory of dependence?
AKA vicarious learning
We learn by copying behaviours of others
Substance misuse can result from peer pressure
What is the neurobiological model for addiction?
All drugs if abuse affect the dopaminergic reward pathway in the brain:
Ventral tegmental area -> prefrontal cortex and lambic system
Prefrontal cortex has a role in motivation + planning
Dopamine release in nucleus accumbens= sensation of pleasure
How do cocaine and amphetamines give pleasure?
Block dopamine reuptake
= increased synaptic dopamine levels
Aetiology of alcohol misuse
Some genetic susceptibility: supported by adoption studies
Occupation: stressful work + socially sanctioned drinking
Social background: difficult childhood, poor educational achievement
Psychiatric illness: assoc with personality disorders, mania, depression, and anxiety disorders
1 unit of alcohol:
1/2 pint normal beer
Small 125ml glass wine
One measure (25ml) spirit
One measure (50ml) fortified win
Units= vol in ml x % alcohol /1000
What are safe levels of alcohol consumption?
Women: 2-3/day, 14/week
Men: 3-4/day, 21/week
What are harmful levels of alcohol consumption?
Women: >6 /day, >35 /wk
Men: >8 /day, >50 / wk
48hrs into abstinence, lasts 3-4 days
Confusion, hallucinations, affective changes, gross tremor, autonomic disturbance, delusions
Mortality rate 5% (30% with sepsis)
Management: reducing benzodiazepine regime and parenteral thiamine, management of potentially fatal dehydration and electrolyte disturbance
What is Wernicke's encephalopathy
Due to acute thiamine (vit B1) deficiency
Confusion, ataxia, opthalmoplegia
Treat with parenteral thiamine
What is korsakoff's syndrome?
Cause by untreated Wernicke's encephalopathy
Irreversible antegrade amnesia
Can register new events but cannot recall them
Patients may confabulated to fill in gaps in memory
What is intoxication?
Transient state of emotional and behavioural change following drug use, dose dependent and time limited
How would you investigate a patient with apparent alcohol misuse?
FBC: macrocytic anaemia (incr MCV) due to B12 deficiency
LFTs: gammaGT rises with recent heavy alcohol use, raised transaminases indicate hepatocellular damage
UDS: if suspect drug misuse too
Hepatitis screen: if suspect IV drug use
What can a UDS: urine drug screen detect?
Amphetamine: 2 days
Heroin: 2 days
Cocaine: 5-7 days
Methadone: 7 days
Cannabis: up to 1 month
How do you assess a patients' motivation to change?
The stages of change model:
Pre-contemplation, Contemplation, Preparation, Action, Maintenance, Relapse
Identify support needed, set realistic goals e.g.
Short term: reduce consumption
Medium term: undergo detoxification
Long term: attend college
How is detoxification managed?
Planned = following period of preparation
Unplanned = e.g. after emergency hospital admission
Long-acting benzos: prevent withdrawal symptoms incl seizures + DT
Gradually withdrawn and stopped
Thiamine: parenteral prophylaxis
What methods are used to support relapse prevention?
Psychological: CBT + group therapy
Acamprosate, anti craving drug thought to act in midbrain
Disulfiram, mimics flush reaction to alcohol making consumption highly unpleasant
How does heroin give pleasure?
A mu opiate agonist it stimulates brain and spinal cord receptors usually acted on by endogenous endorphins
How is heroin taken?
Initially often smoked
IV injection: antecubital fossa -> feet, backs of hands, groin
Veins become damaged
Subcutaneous 'skin popping' or IM
What are local complications of IVDU?
DVT: femoral injection damages valves slowing venous return
Emboli: can cause gangrene and consequently amputation