5.3 Drugs

Question 1

Psychoactive drugs

Answer 1

naturally occurring or synthetic drugs that change a conscious experience

Question 2

What can psychoactive drugs do to you?

Answer 2

• You can become tolerant to these drugs after prolonged usage

Question 3

Definition of tolerance?

Answer 3

Reduction in effects experienced by the user

Question 4

Definition of addiction?

Answer 4

compulsive usage despite negative consequences

Question 5

What is an agonist?

Answer 5

a substance that mimics neurotransmitters

Question 6

What is an antagonist?

Answer 6

A chemical or drug that binds to a receptor to prevent the binding of agonist

Question 7

What do depressants do in low and high doses?

Answer 7

Generally slow CNS activity
Low: relaxation and sedation
High: slows down heart rate and brain activity

Question 8

Examples of types of depressants?

Answer 8

Alcohol
Sedatives
Opiates

Question 9

Facts about alcohol?

Answer 9

• The absorption rate depends on food in stomach and the body mass of the person
• alcohol increases the effect of GABA
• alcohol decreases the effect of glutamate
• Prolonged heavy drinking actually shrinks the brain
• There are health benefits with light use of alcohol

Question 10

Facts on sedatives?

Answer 10

• benzodiazepines are the most common type of sedative
• Sedatives are taken to reduce anxiety, arousal, insomnia
• Sedatives act as GABA agonists (mimics GABA)

Question 11

Facts on opiates?

Answer 11

• they mimic endogenous opiates
• Reduce pain, elevate mood, feelings of bliss/ euphoria
• derived from opium
  - natural sources ( Morphine)
  - partially synthetic sources (heroin)
  - entirely synthetic (methadone, oxycodone,
  hydrocodone)
• high potential for abuse

Question 12

What are stimulants?

Answer 12

They activate the nervous system and produce arousal

Question 13

Types of stimulants?

Answer 13

• caffeine
• nicotine
• cocaine
• amphetamines
• ecstacy

Question 14

Caffeine facts?

Answer 14

• coffee, tea, cocoa, soft drinks, energy drinks
• increased alertness, heart rate, loss of motor control, insomnia, nervousness
• physical dependence equals withdrawal symptoms common

Question 15

Nicotine facts?

Answer 15

• from tobacco
• increased heart rate, respiration, feelings of arousal
• relaxes skeletal muscles
• EXTREMELY ADDICTED which means you can be highly tolerant and it has unpleasant withdrawal symptoms
• decreased life expectancy increased lung cancer risk

Question 16

Cocaine facts?

Answer 16

• isolated from coca leaf
• increases availability of dopamine, serotonin, noradrenaline
• short-lived euphoria
• different forms ( smoke crack cocaine, injections)
• addictive

Question 17

Amphetamine facts?

Answer 17

• synthetic
• long-lasting excitation of the sympathetic nervous system
• increase heart rate, motivation, elevates mood
• meth, Dexedrine, benzedrine (speed)
• used to treat ADHD
• long-term use - depression, paranoia, loss of bodily control, psychosis

Question 18

Ecstacy (MDMA) facts?

Answer 18

• chemically similar to meth and hallucinogenic mushrooms, therefore a stimulant and mild hallucinogen
• Physiological arousal, mild hallucinogen
• “The love drug” feelings of affection, euphoria, connectedness
• neurotoxin
  - can lead to long-term depression, cognitive defects, impulsivity

Question 19

Types of hallucinogens?

Answer 19

• Marijuana

- LSD

Question 20

What do hallucinogens do?

Answer 20

create distorted perceptions of reality ranging from mild to extreme

Question 21

Marijuana facts?

Answer 21

• Cannabis sativa plant
• Tetrahydrocannabinol (THC)
• Endocannabinoid neurotransmitters
• changes perception of time and food
• No physical dependence, however psychological dependence is common
• memory impairment
• medical uses

Question 22

LSD facts?

Answer 22

-Lysergic acid diethylamide - 25 or “acid”
- derived from the grain fungus ergot
- stimulates particular subtype of serotonin receptor
- increases glutamate in the cortex
- Profound effects on perception
- color perception, hallucinations, life-altering
experiences

Question 23

Point of commonality?

Answer 23

There are similarities between all of these drugs in terms of they all have to do with dopamine

Question 24

Dopamine

Answer 24

• an important role in mood and arousal
  Especially positive mood
• plays major role in reward-related behaviour

Question 25

Dopamine as the point of commonality

Answer 25

• Mesolimbic dopamine (from midbrain to limbic striatum)
  - ventral tegmental area (VTA) –> nucleus accumbens
  (NAcc)
• particular pathway where dopamine is most responsive to rewards ^
• Natural stimuli activate this track that stimulates dopamine but drugs can also activate this track if natural stimuli is not present
• Both natural stimuli and drugs of abuse activate mesolimbic dopamine
• Drugs of abuse bypass this sensory pathway:
  - opiates: act on opioid receptors located on VTA cell bodies (reduce the amount of GABA)
  - marijuana: acts on CB receptors in VTA
  - cocaine/ amphetamine: ups the dopamine reuptake and reduces the dopamine release in the NAcc

A lot of these drugs increase dopamine which is why we like them
Others inhibit the inhibitor, GABA, which results in the flow of these neurotransmitters
- directly increases dopamine
- indirectly increases dopamine

Question 26

Adaptation of dopamine?

Answer 26

• dopamine release to natural stimuli rapidly undergoes habituation
• drugs of abuse do not show within-session habituation BUT
• After chronic drug use, dopamine decreases in NAcc
  - means craving