drug addiction

Question 1

what is addiction?

Answer 1

• state of periodic or chronic intoxication produced by repeated consumption of drugs

Question 2

what are the signs of addiction?

Answer 2

• cravings
• physical dependence
• withdrawal symptoms
• poor judgement
• neglect of responsibilities

Question 3

how do drugs link to pleasure?

Answer 3

• drugs heighten dopamine/GABA/serotonin levels which stimulate the dopamine reward pathway in the limbic system so we receive pleasure

Question 4

how do drugs work in general?

Answer 4

change neurotransmitters by:
- increasing dopamine levels
- preventing re-uptake
- increasing/decreasing other NT like GABA

Question 5

what is desensitisation?

Answer 5

• If receptor constantly stimulated by extra
  NT it will have diminished responsiveness (caused by down-regulation) meaning more drugs with have to be taken to feel pleasure

Question 6

what is drug withdrawal?

Answer 6

• symptoms that occur with abrupt discontinuation of or decrease in drug use

Question 7

how does cocaine affect synaptic transmission?

Answer 7

• blocks re-uptake of NT like dopamine/noradrenaline/serotonin
• binds to transporters that normally remove excess NT from synaptic gap, preventing them from being re-absorbed increasing their concentration in the synapses so their natural effects on post-synaptic neuron amplified
• neurons then become dependent due to energy and confidence a person gains

Question 8

how does heroin (opioid) affect synaptic transmission?

Answer 8

• opioids bind to opiate-specific receptors within brain, decreasing the body’s perception of pain and elevating mood by increasing dopamine

Question 9

how does nicotine affect synaptic transmission?

Answer 9

• disrupts the normal relationship between acetylcholine and its receptors
  nicotine shaped similarly to acetylcholine, so can fit in the same receptors and
  act just like it
• after repeated use of nicotine, theres more activity at acetylcholine receptors than usual because they’re being activated by both acetylcholine and nicotine.
• change in balance causes brain to “think” theres too much acetylcholine so
  reduces number of receptors and amount of acetylcholine released into synapse brain now needs nicotine to maintain normal functioning
• causes an increase in the release of dopamine from neurons located in the
  limbic system

Question 10

how does alcohol affect synaptic transmission?

Answer 10

• alcohol suppresses release of glutamate,
  resulting in a slowdown along your brain’s highways.
• releases GABA reducing energy levels
  depressant effects of alcohol:
• suppresses the excitatory NT glutamate
• increases the inhibitory NT GABA