Substance misuse & addiction Flashcards
What are the ICD-10 criteria for substance use dependence syndrome? How many are required for a diagnosis?
- strong compulsion
- difficulties controlling substance taking behaviour
- withdrawal
- tolerance
- neglecting alternative interests
- persisting despite evidence of clear harm
3 or more in the last year
What is the difference between addiction and dependence?
Addiction: compulsive drug use despite harmful consequences, with an inability to stop
Dependence: physical adaptation to the substance seen
Can be dependent but not addicted
How does alcohol target the excitatory glutamate system in the brain?
Blocks excitatory system
Targets & blocks NMDA receptors
Impaired memory
How does alcohol target the inhibitory GABA-benzodiazepine system in the brain?
Stimulates inhibitory system
Increases benzodiazepine-GABA-A receptor coupling activity
Increased sedation and anxiolysis
How does tolerance to alcohol happen?
Neuroadaptations so that GABA & glutamate balance remains the same in the presence of alcohol
Increased NMDA receptors
Decreased GABA-A receptors/change in subunits so less sensitive to alcohol
How does alcohol tolerance lead to a withdrawal state?
Increased number of NMDA receptors relative to GABA-A
Increased Ca2+ and upregulated excitatory system
Leads to seizures and atrophy
What drugs can be given to reduce effects of alcohol withdrawal?
Benzodiazepines
e.g. chlordiazepoxide, diazepam, lorazepam
Where in the brain is the dopamine system found?
Ventral striatum
How do amphetamines directly affect the dopamine reward pathway?
Block reuptake of dopamine from synaptic cleft back into pre-synaptic terminal
Enhances release of dopamine from pre-synaptic terminal
What is the indirect effect of drugs of abuse on the dopamine reward pathway?
Increases dopamine neuron firing in the ventral tegmental area of the brain
What transitions can be seen in the brain when voluntary drug usage becomes more habitual/compulsive?
Prefrontal to striatal control over drug taking
Ventral to dorsal stratum
How is ethanol metabolised in the body? Which enzymes are involved?
Oxidised to acetaldehyde, then to CO2 and H2O
By alcohol dehydrogenase and acetaldehyde dehydrogenase
What is CAGE screening?
Have you felt you need to cut down on drinking?
Do people annoy you by criticising your drinking?
Do you feel guilty about drinking?
Do you wake up wanting to drink? (eye opener)
What is delirium tremens? How many hours after cessation of alcohol use can it occur?
Medical emergency
Confusion, hallucinations, tremor, agitation
48-72 hours post-drinking
What is the difference between opiates and opioids?
Opiates: natural
Opioids: synthetic or semi-synthetic
