Drug Addiction 1 Flashcards
What are stimulants? Give a few examples.
3 marks
- Amphetamines
- Cocaine
- Caffeine
Pyschic addiction can be moderate to severe
What are sedatives and hypnotics? Give a few examples.
2 marks
- Alcohol
- Barbiturates - used for treatment of anxiety ot insomnia
- Benzodiazepines
can range from mild to severre addictiona nd abrupt withdrawal may be fatal
What are opiates and opioid analgesics? Give a few examples.
3 marks
- Morphine and codeine
- Heroin
- Fentanyl
Addiction ranges from mild to severe, abrupt withdrawal unlikely to be fatal
What drug groups are known to cause addiction?
4 marks
- Stiulatns
- Sedatives and hypnotics
- Opiate and opioid analgesics
- Nicotine
Define ‘drug abuse’
2 marks
Voluntary but excessive form of self administering of any chemical for recereational purposes
How is addiction a disease of the brain?
2 marks
- Causes persistent changes in brains structure and function
- compulsive use
- continues despite negative consequences
What is substance dependence?
1 mark
More severe, corresponds roughly with addiction
What is substance abuse?
1 mark
May or may not lead to substance dependence
What is substance abuse disorder?
1 mark
Individual has maladaptive pattern of substance use for at least 12 months - led to significant impairment or distress by clinical standards
What can long term drug exposure lead to?
4 marks
- Tolerance
- need to increase dose of drug for same effect
- Sensitization
- enhancement of drug responses as result of repeated drug exposure
- Dependence
- adapted physiological state of cells/ systems that develops to compensate for excessive stimulation by a drug
- Withdrawal syndrome
- drug intake stops, unmasking of adapted state get withdrawal syndrome - may have somatic components as well as affective and motivational components
What factors cause a signifcant contribution to drug abuse and addiction?
Possible genetic variants overlapping with environmental influences
What have GWAS for alcohol shown?
2 marks
- Lots mutations in metabolism for alcohol show portective effect
- Mutated ALDH2 - facilitates the degradation of alcohol therefore have higher tolerance
What was the consequence of a nicotine receptor mutation?
2 marks
Protective effect showed increased protection from nicotine
Mutation in nicotinic-R
What is ultimately the main risk for addiction?
Adminstering the drug itself
Receptors for which monoamines have been implicated in alcoholism and tobacco addiction?
2 marks
Dopamine receptors (alcoholism)
Acetylcholine receptors (nicotine)
Which is responsible for acute rewarding and reinforcing effects of abused drugs?
1 mark
The reward circuit - driven by monoamines and glutamate
Where does the VTA project to and what happens following that?
1 mark
- Projects anteriorly to the striatum - NAc and release of DA leads to pleasure in the NAc
Activation of which drug in particular is important in the reinforcement of drugs?
1 mark
Mesolimbic DA pathway
What does the PFC have a role in?
2 marks
- Executive function, planning, organization in problem solving, mental flexibility and valuation of incentives
- Contribution to regulation of emotional and motivational processes
Define impulsitivity.
2 marks
- Behaviour occurs quickly without control, connected with immediate positive consequences
- Long term porbably yields negative consequences
Define compulsitivity.
2 marks
- Performed an act persistently and repeptively without it necessarily leading to an actual reward or pleasure - could be an attempt to make an obssession go away
What happens on a neurophysiological level during each of these phases:
Early phases
Drug seeking habits
Established compulsion
3 marks
Early phases:
- No longer releasing DA in NAc the dorsal striatum so increase in DA. No longer limited to ventral striatum. with this the PFC starts losing its negative contorl over these areas
Drug seeking habits:
- Motor cortex gains function with increase in DA and more compulsive behaviour
Established compulsion:
- Failure to disengage dorsal striatum
Refer to slide 39 - read through figure legend and recall do this x3
How does drug addiction override the positive control circuits?
3 marks
- Enhances the exxpectation value of the srug in reward
- Favours a positive feedback loop intiated by consumption
- Perpetuated by enhances activation of the moitvation/drive and memory circuits
How is dopamine concentration affected in a drug user brain?
1 mark
- INcreased as sopamine receptors are reduced/ too much dopamine so there’s slower intake
