Pschiactric Disorders, Drug Addiction And Action

Question 1

What is an Antagonist?

Answer 1

They inhibit transmissions at synapse and block neurotransmitters

Question 2

What is an Agonist?

Answer 2

They facilitate transmission at synapse, they increase or mimic neurotransmitters

Question 3

Describe affinity and efficacy

Answer 3

If a drug has a high AFFINITY for a receptor it binds to it

If a drug has a high EFFICACY for a receptor it activates it

Question 4

What is the relevance of the nucleus accbens?

Answer 4

Most drugs stimulate the release of dopamine

Drug-sustained bursts of dopamine-inhibits GABA-increased activity in nucleus accumbens

Question 5

Give an example of a stimulant

Answer 5

Amphetamine (speed) stimulates dopamine synapse by increasing release of dopamine from presynaptic terminal

Question 6

Give an example of a stimulant

Answer 6

Cocaine: blocks the reuptake of dopamine thus prolonging effects (accumulation of dopamine in the synaptic cleft)

Question 7

What do stimulants do?

Answer 7

Increase in dopamine causes a widespread reduction of activity in the brain except the nucleus accumbens. Followed by a crash as the dopamine disappears it can’t be replaced quickly enough.

Question 8

What is an opiate (with examples)

Answer 8

Morphine and heroin: increased relaxation and decreased pain sensitivity.
Mimic endorphins, it attaches to specific endorphin receptors. Inhibits GABA, thus increases dopamine. Also hindbrain area that usually releases norepinephrine
Reduces stress but also memory storage.

Question 9

Describe marajuana

Answer 9

Contains cannabisoids, which bind to specific receptors
Inhibit GABA release, increase dopamine therefore you have a perception of heightened awareness.
Cannabisoid receptors are abundant in the hypothalamus, the feeding section of the brain, increased hunger ‘munchies’

Question 10

Describe botolinium toxin (Botox)

Answer 10

It is a deadly neurotoxin released by decaying food. An antagonist which blocks release of acetylcholine at neuromuscular junctions which causes paralysis. Small doses are used to reduce muscle tremors and cosmetically.

Question 11

Describe addiction

Answer 11

Drugs increase the ‘need’ for the substance even if the experience is not pleasant

Question 12

Describe sensitisation of the nucleus accumbens

Answer 12

The nucleus accumbens becomes more sensitive to substances after repeated use; increased ability to release dopamine in response to the substance. Reduced sensitivity to other things.

Question 13

Describe withdrawal

Answer 13

Cravings for the drug. Relapse causes increased sensitivity. User learns that drug relieves stress related to withdrawal and so craves it more during future withdrawal.

Question 14

What is addiction?

Answer 14

Continued use of a substance when it interferes with your life

Question 15

Describe alcohol effects.

Answer 15

Alcohol affects many areas of the brain-mostly inhibitory, it relaxes Brain activity and communication.

Question 16

What types of alcoholism are there?

Answer 16

1) late onset (after 25) gradual, men=women, less severe (few relatives with alcoholism
2) early onset (before 25) rapid, men more than women, more severe (more relatives with alcoholism)

Question 17

Why are people alcoholics?

Answer 17

Genetic influence: coding for increased risk taking, coding for increased stress response: more likely to relapse

Sons of alcoholic fathers:

1) high alcohol tolerance
2) greater decrease of stress when consuming
3) smaller amygdala (risk taking)

Question 18

Describe depression (general)

Answer 18

Twice as common in women than men. (5%of adults)
Hereditary, not specifically for depression. More common for relatives of women with early onset depression.
Low serotonin turnover associated with aggression and depression. Implication of gene controing serotonin. Transporter protein, this controls the ability of an axon to reabsorb serotonin. (Short and long)

Question 19

What is postpartum depression?

Answer 19

After giving birth. 20% of all women suffer, only 0.1% long lasting

Question 20

What is bipolar depression?

Answer 20

Vary between mania and depression. Can be treated with lithium salt
Blocks synthesis of arachidonic acid

Question 21

What is seasonal affective disorder (SAD)?

Answer 21

Usually associated with winter, common near poles, where there are long nights, (affects circadian rhythm) less severe than depression- can be treated with light therapy.

Question 22

Describe schizophrenia

Answer 22

Means split mind-emotional v intellectual
Some patients show inappropriate emotional expression detached from circumstances. Hallucinations, delusions, thought disorders- can be acute or chronic. 
Positive symptoms (additions): delusions etc
Negative symptoms (absences): poor social interaction etc

Question 23

What are problems with schizophrenia diagnosis?

Answer 23

Difficult to diagnose as often confused with other conditions. Difficult to pinpoint specific brain areas.

Question 24

What are schizophrenia demographics?

Answer 24

More common in men than women, earlier onset in men. 1% of all population. Equal promotions in cultures and populations thus may have a genetic basis. Why has it evolved? May be a byproduct of language…?

Question 25

What is the neurodevelopmental hypothesis?

Answer 25

Abnormalities in development of the nervous system before birth and in neonates.

1) infections, poor nutrition,
2) slight brain abnormalities

Larger ventricles, less space for brain cells (relate to age and Indiv diff)

Prefrontal cortex damage (working memory)

Smaller cell bodies in hippocampus (mem consolidation)

Less lateralisation (right plenum temorale larger, language deficit? Left handed)

Question 26

How can drug abuse affect psychosis?

Answer 26

Drug abuse associated with excess dopamine which can cause psychosis. This is the dopamine hypothesis=excess activity in dopamine synapses, twice as many dopamine receptors but normal level of dopamine.

Dopamine inhibits glutamate- inhibits dopamine- angel dust- PCP

Question 27

What are drugs?

Answer 27

Tend to imitate substances already present in our nervous system, particularly those that affect transmissions at the synapse.
Mainly from plants (eg nicotine from tobacco plants
Plant produces these to attract insects to avoid being eaten etc
Nervous system of many animals similar