drugs and addiction e lecture

Question 1

what is the process of neurotransmission

Answer 1

-action potential on presynaptic neuron
-causes vesicles to move to axon terminals
-vesicles bind to cell membrane and fuse enabling vesicles to release neurotransmitters into synaptic cleft
-neurotrans. diffuse across cleft and bind to receptors on post synaptic neuron
-this can trigger an action potential in the post synaptic neuron
-once messaged is relayed, post synaptic neuron releases neurotrans. back into synaptic cleft
-some are degraded by enzymes (acetylcholinesterase) and some taken back into presynaptic neuron in reuptake

Question 2

what is an excitatory response

Answer 2

neurotrans makes neuron more likely to fire

Question 3

what is inhibitory response

Answer 3

neurotrans makes neuron less likely to fire

Question 4

diff drugs for diff neurotrans.

Answer 4

-some are very specific and some have a variety of actions
-neurotrans have sub receptors and drugs often work selectively on certain sub receptors

Question 5

how can antagonists prevent neurotransmission

Answer 5

-prevent storage of neurotransmitters in vesicles
-drug can prevent release of neurotransmitters into synaptic cleft
-drug can block post synaptic receptors
-drug can inactivate enzymes to inhibit synthesis of neurotransmitters
-can stimulate reuptake or inhibit release of neurotransmitters

Question 6

how can agonists increase neurotransmission

Answer 6

-drugs serve as a precursor (synthesises neurotransmitter)
e.g tryptophan is precursor to serotonin- precursors are amino acids
-drug can stimulate release of neurotransmitter into synaptic cleft
-drug stimulates post synaptic receptors
-drug block reuptake and blocks autoreceptors
-drug inactivates acetylcholinesterase

Question 7

what is the nature of addiction

Answer 7

-ongoing disagreement

Question 8

what is drug addiction

Answer 8

or substance dependence is a chronically relapsing disorder
-compulsion to seek or take a particular drug
-loss of control in terms of limiting intake
-neg emotional state (dysphoria, anxiety etc) when drug prevented
-no comprehensive globally accepted theory for addiction

Question 9

features of addiction

Answer 9

-tolerance
-withdrawal
-compulsive engagement with drug
-neural mechanisms
-craving/obsessive focus on drug
-relapse
-physical/psychological dependence
(physical dependence leads to physical withdrawal symptoms)
(psychological dependence leads to craving/obsession

Question 10

physical withdrawal symptoms

Answer 10

-due to neuroadaptation
-as drug wears off, uncomfortable physical symptoms occur
e.g heroin = cramps, convulsions, sweating, goose bumps, flu like symptoms
e.g alcohol = (heavy chronic drinkers) tremors, fevour, seizures, hallucinations, fatigue, nausea, vomiting, high BP and HR, headaches etc

Question 11

how to reverse withdrawal symptoms

Answer 11

take the drug, negative reinforcement as prevents these horrible withdrawal symptoms
leads to relapse

Question 12

half life of drug and withdrawal

Answer 12

-shorter the half life, the shorter the withdrawal syndrome
-after physical symptoms subside, dissociation seen between physical and psychological symptoms

Question 13

what is conditioned withdrawal

Answer 13

-pairing of cond stimulus with withdrawal which leads to CR later
-later the CS from the environment can be enough to induce withdrawal
-can lead to relapse, if they feel withdrawal bc of CS cues in environment
-relapse may occur in familiar scenes

Question 14

what is addiction according to DSM 5

Answer 14

-has 11 features
-2/3 criteria = mild substance dependence
-4/5 = moderate substance dependence
6 + = severe substance dep

examples of criteria include:
-taking substance in large amounts for longer than intended
-wanting to cut down/stop but not feeling able to
-cravings and urges to use
-not managing to work, go to school bc of substance
etc etc

Question 15

ICD criteria for substance dependence (used by UK and others)

Answer 15

-must demonstrate presence of 2 or more from guideline of 3

1.impaired control over substance use
2.substance becomes an increasing priority in life
3.physiological features (neuroadaptation, tolerance etc)

Question 16

what is the addiction cycle

Answer 16

volkow

• preoccupation anticipation - binge intoxication - withdrawal

Question 17

preoccupation/anticipation stage

Answer 17

-precedes drug use
-very difficult to measure in humans, does not correlate well with relapse (Tiffany et al 2000)
-pp are unlikely to say they were craving a drug, people tend not to use the word craving when describing a relapse

Question 18

what creates preoccupation/anticipation

Answer 18

-priming dose of drug, small dose can increase craving
-drug associated cues = places, objects, stimuli associated with drug
-exposure to stressors

Question 19

binge/intoxication stage

Answer 19

-immediate pos reinforcement of drug
-biggest predictor in drug use is already having participating in drug use
-conditioned place preference: pavlovian cond, animals exhibit cond place preference for environment previously associated with drugs
-drugs of abuse decrease threshold for brain stimulation
-reward, correlation between this effect and abuse potential of drug
-associated with neural pathways, biology reinforcement (pos reinforcement also comes from social/cultural practice of drug use)

Question 20

withdrawal neg affect stage

Answer 20

-uncomfortable physical/psychological state
-animals avoid environment associated with withdrawal
-reward thresholds increase (reverse tolerance)
-changes to neural pathway contributing to neg emotional state and neg reinforcing properties of drug seeking