Addiction and Substance Misuse Flashcards
Define hazardous drinking?
A pattern of alcohol consumption that increases the harmful consequences for the user (not currently a diagnostic term)
Drinking > 14 units a week but < 35 units for women
Drinking > 14 units a week but < 50 units for men
Define harmful drinking?
A pattern of alcohol consumption that is causing mental or physical damage
> 35 units a week for women
> 50 units a week for men
Criteria used to diagnose any dependence?
3 or more for at least 1 month:
1) sense of compulsion
2) craving
3) physiological withdrawal
4) evidence of tolerance
5) preoccupation with substance use
6) persistent use despite harmful consequence
Diagnosis of alcohol withdrawal?
Any 3 of the following:
- tremor of outstretched hands, tongue or eyelids
- sweating
- nausea, wrenching or vomiting
- tachycardia or hypertension
- anxiety
- psychomotor agitation
- headache
- insomnia
- malaise or weakness
- transient visual, tactile or auditory hallucinations or illusions
- generalised tonic clonic seizures
What is the most serious withdrawal state?
delirium tremens
When does delirium tremens typically occur?
1-3 days after alcohol cessation
Presentation of delirium tremens?
patients are disorientated, agitated and have a marked tremor as well as tactile visual hallucinations (insects or small animals crawling on them)
signs include sweating, tachycardia, tachypnoea and pyrexia
What cause Wernicke Korsakoff syndrome?
thiamine deficiency (alcohol is one of the causes of thiamine deficiency)
Describe wernickes encephalopathy?
acute thiamine deficiency cytotoxic oedema in mamillary bodies ocular dysfunction ataxic gait acute confusion reversible but needs urgent recognition and thiamine replacement so that it doesn't progress to Korsakoff syndrome
Why does wernickes encephalopathy need urgent recognition?
it is reversible if caught early and patient given thiamine however if not then it can progress to korsakoff syndrome which has a much poorer outcome
Cytotoxic oedema in mamillary bodies?
wernickes encephalopathy
Describe korsakoff syndrome?
chronic thiamine deficiency
cerebral atrophy resulting from WE
profound anterograde and retrograde amnesia
confabulation to fill in memory gaps
generally lack insight
abstinence and nutrition is key in treatment but generally chances of recovery are low
Describe the process of acute alcohol withdrawal?
- Reassurance
- long acting benzodiazepines (as they are cross tolerant with alcohol due to action on GABA A) either diazepam or chlordiazepoxide and titrate against severity of withdrawal symptoms gradually reducing over 7 days or more
- vitamin supplementation
- thiamine as prophylaxis for WE (increase dose if WE symptoms)
Describe location of alcohol detoxification?
most patients can be detoxified in the community but if severe they should be inpatients
delirium tremens requires immediate transfer to a medical ward
Describe psychosocial intervention for alcohol relapse prevention?
Type depends on patient as they are all effective if matched appropriately
- CBT
- Motivational enhancement therapy
- 12 step facilitation therapy
- behavioural self control therapy
- family and couple therapy
Describe pharmacological management to prevent relapse in alcohol misuse disorders?
- there is no place for benzodiazepines beyond detox
- naltrexone is 1st line, it is an opioid antagonist and reduces the reward from alcohol
- disulfiram (antabuse) inhibits alcohol dehydrogenase leading to accumulation of acetaldehyde if alcohol ingested (this causes unpleasant symptoms: flushed skin, tachycardia, nausea and vomiting, arrhythmias, hypotension), need patient compliance
- acamprosate acts centrally on GABA and glutamate to reduce cravings
What pathway is the reward pathway?
mesolimbic pathway
Dopaminergic activity in the mesolimbic pathway is ____1___ ____2_____ ____3____
1) is a motivating signal
2) it incentivises behaviour
3) is involved in normal pleasurable experiences
All drugs of abuse have effects on ______
dopamine level and the end result is dopaminergic activity within the mesolimbic pathway (although all drugs act in slightly different ways)
Why do people want to seek out drugs continually?
because they activate the reward pathway
Explain the neurobiology of tolerance?
repeated exposure to the drug leads to down regulation of dopamine receptors, meaning more is needed to get the same response (tolerance)
this down regulation means threshold for rewards during abstinence is increased and normal experiences no longer evoke adequate reward response (these changes persist despite prolonged abstinence from substance abuse)
Describe the prefrontal cortex, what it does to the mesolimbic pathway and its role in addiction?
The prefrontal cortex puts the brakes on the reward pathway however it is not fully mature until 20s so is vulnerable whilst developing (younger people are more impulsive as the mesolimbic pathway is in control, younger people will also have a longer course with drugs if they start them)
The prefrontal cortex is dysfunctional in addicted people
Apart from the mesolimbic pathway and prefrontal cortex, name 3 other things implicated in the development of addiction?
hippocampus, amygdala and stress
Explain how stress can make addiction worse or cause addiction?
chronic stress leads to dampening of dopaminergic activity through down regulation of D receptors which reduces sensitivity to normal rewards encouraging exposure to highly rewarding behaviours e.g. drug taking hence stress plays a role in addiction
2 categories of treatment for opiate misuse?
psychosocial intervention and medical treatment - should be a joined approach
2 drugs that can be used as a substitute for heroin?
methadone
buprenorphine
Explain why methadone can be used as a substitute for heroin?
- cross tolerance means the person will be equally tolerant to methadone
- cross suppression between methadone and heroin allows methadone to prevent or reverse withdrawal symptoms
- methadone can be taken orally 1 x a day vs heroin by needle 3-4 x a day
- higher doses of methadone block the euphoric effect of heroin discouraging illicit drug use
Opioid overdose can be treated with?
naloxone
Compare methadone and buprenorphine?
methadone: mu receptor agonist oral prolongs QT interval can cause sedation
buprenorphine:
mu receptor partial agonist
sublingual tablets
less likely to cause overdose as only a partial agonist
