Psychiatric Disorders, Drug Action and Addiction

Question 1

What are drugs?

Answer 1

Tend to imitate substances already present in our nervous system, particularly those that affect transmission at the synapse

Question 2

Why do drugs tend to imitate substances already present in our nervous system

Answer 2

• Mainly from plants (e.g. nicotine - tobacco plant)
• The plant produces these chemicals to attract insects, to stop being eaten etc., or for own processes

Question 3

Name the 2 ways that drugs affect transmission at the synapsy

Answer 3

• Antagonist
• Agonist

Question 4

Describe an Antagonistic drug

Answer 4

• Inhibit transmission at the synapse
• Block neurotransmitter

Question 5

Describe an Agonistic drug

Answer 5

• Facilitate transmission at the synapse
• Increase effects of neurotransmitter, or mimic the neurotransmitter

Question 6

How much affinity do drugs have?

Answer 6

Drug has a high affinity for a receptor if it binds to that receptor

Question 7

How much efficacy do drugs have?

Answer 7

Drug has a high efficacy if it has a tendency to activate that receptor

Question 8

What do most drugs stimulate?

Answer 8

Most drugs stimulate the release of dopamine

Particularly in the nucleus accumbens

Question 9

Define the nucleus accumbens

Answer 9

small subcortical area rich in dopamine receptors

Question 10

How do drugs work?

(diagram)

Answer 10

Question 11

Name 2 stimulants?

Answer 11

> Amphetamine (Speed)

> Cocaine

Question 12

What does Speed do?

Answer 12

Stimulates dopamine synapses by increasing the release of dopamine from presynaptic terminal

Question 13

What does Cocaine do?

Answer 13

Blocks the reuptake of dopamine, thus prolonging effects

Question 14

Why are stimulants followed by a crash?

Answer 14

Dopamine washes away, can’t be replaced quick enough

Question 15

Name 2 Opiates

Answer 15

> Morphine

> Heroine

Question 16

How do Opiates work?

Answer 16

1. Inhibits GABA, so increases dopamine
2. Also blocks a hindbrain area that usually releases norepinepherine

Question 17

What does Marijuana consist of

Answer 17

> Contains cannabinoids

> Bind to specific cannabinoid receptors (widespread in the brain)

Question 18

What does marijuana do to the brain?

Answer 18

1. Inhibit GABA release (increase in dopamine release in nucleus accumbens) = perception of heightened awareness
2. Cannabinoid receptors abundant in hypothalamus (feeding!) = increased appetite

Question 19

How do the functioning of drugs relate to addiction?

Answer 19

• Many addictive substances increase activity at dopamine synapses
• Particularly in the nucleus accumbens

Question 20

What is the difference between liking and wanting drugs?

Answer 20

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

• Mice with increased dopamine production showed no more pleasure in food, but made more effort to get it
• Mice with decreased dopamine production made less effort to get food, but ate just as much.

(Kalat)

Question 21

How does the sensitization of the nucleus accumbens relate to drugs?

Answer 21

– Becomes more sensitive to substances after repeated use

– Increased ability to release dopamine in response to the substance

– Reduced sensitivity to other things

Question 22

How does the withdrawal symptoms of drugs relate to addiction

Answer 22

– Cravings for the drug

– Relapse causes increased sensitivity

– User learns that the drug relieves distress associated with withdrawal, and so craves it more during future withdrawal

Question 23

Name something that can counter addiction

Answer 23

Varenicline (CHAMPIX), treatment for smoking

Question 24

What is the functio of valenicline

Answer 24

Partial nicotine receptor agonist.

Stimulates and binds the nicotine agonist

Question 25

How does alcohol affect the brain?

Answer 25

Alcohol acts on many areas of the brain – mainly inhibitory effects

Question 26

State the 2 types of alcoholism

Answer 26

Type 1 and 2

Question 27

Describe Type 1 alcoholism

Answer 27

Late onset (after 25) Gradual onset Equal men and women Less severe

Question 28

Describe Type 2 alcoholism

Answer 28

Early onset (before 25) Rapid onset More men than women Severe

Question 29

Can Genes influence alcoholism?

Answer 29

Genes might influence alcoholism in many ways (not as simple as ‘a gene for alcoholism’

Question 30

Give an example of how genes may influence alcoholism

Answer 30

1. Coding for an increase in risk taking behaviour 2. Coding for an increased stress response = more likely to relapse after quitting

Question 31

Do sons of alcoholic fathers show predispositions to alcoholism?

Answer 31

1. Show less than average intoxication – tolerance to alcohol 2. Show greater decrease of stress when drinking 3. Slightly smaller amygdala (therefore increased risk taking?)

Question 32

Define Clinical/Major Depression

Answer 32

Feelings of extreme sadness and helplessness Severe enough to interfere with daily life, and can last for weeks or months rather than days

Question 33

Can Serotonin be a cause of depression?

Answer 33

low serotonin turnover associated with aggression AND depression So genes controlling serotonin have been implicated

Question 34

What study supports the suggestion that serotonin might be a cause of depression

Answer 34

Caspi et al. (2003)

Question 35

What did Caspi et al. (2003) find?

Answer 35

- gene controlling the serotonin transporter protein - this protein controls the ability of an axon to reabsorb serotonin (recycling)

Question 36

What types of depression genes are there, and how do they affect a person's depression

Answer 36

Short and long types If you have two short forms of the gene = more likely to have depression in response to stressful events

Question 37

Define Postnatal Depression (postpartum)

Answer 37

Depression after giving birth

Question 38

Define Unipolar Disorder

Answer 38

Varying between normality and depression

Question 39

Define Bipolar Disorder

Answer 39

Varying between mania and depression (formally manic depression)

Question 40

How is Bipolar disorder treated?

Answer 40

Treated with lithium salts - Block synthesis of arachidonic acid (associated with brain inflammation)

Question 41

What does SAD stand for?

Answer 41

Seasonal Affective Disorder (SAD)

Question 42

What is Seasonal Affective Disorder?

Answer 42

- depression associated with one season (usually winter) - common near the poles where the nights are long (circadian rhythms!) - less severe than major depression - light therapy as treatment (affects biological clock)

Question 43

Define Schizophrenia

Answer 43

'Split Mind' the SPLIT refers to a division between emotional and intellectual experiences and behaviour

Question 44

What are the symptoms of schizophrenia

Answer 44

Some patients show inappropriate emotional expression that seems detached from current circumstances Hallucinations, delusions, thought disorder, movement disorder Can be acute or chronic

Question 45

Name the types of symptoms in schizophrenia

Answer 45

\> Positive Symptoms (additions) \> Negative Symptoms (absences)

Question 46

Name the two types of positive symptoms in schizophrenia

Answer 46

Psychotic - delusions and halucinations Disorganised - odd emotional and thought disorder

Question 47

Name the 3 types of negative symptoms of schizophrenia

Answer 47

\> Poor social interaction \> Poor speech \> absent facial expression

Question 48

Name the problem with schizophrenia

Answer 48

Not all patients exhibit all symptoms - difficult to diagnose, often confused with other conditions - difficult to pinpoint a specific brain area

Question 49

What demographic data is there about schizophrenia

Answer 49

More common in men Earlier onset in men Present in 1% of the population Equal proportions in all cultures/populations

Question 50

What did Kalat find?

Answer 50

It is more likely to develop in closely related individuals (i.e. MZ twins or a child of two schizophrenic parents)

Question 51

What did Kalat's findings suggest?

Answer 51

May not be one gene, but instead a combination of genes interacting with the environment

Question 52

Name 2 ways which are theorised to be the cause of development of schizophrenia?

Answer 52

Neurodevelopmental hypothesis Brain abnormalities

Question 53

Define Neurodevelopmental hypothesis

Answer 53

abnormalities in the development of the nervous system before birth (prenatal) and in the newborn

Question 54

Explain the Neurodevelopmental hypothesis

Answer 54

1. Infections, poor nutrition, complicated delivery BUT, only increases chance of schizophrenia slightly 2. Some slight brain abnormalities in patients, suggesting subtle changes during development

Question 55

Name Brain Abnormalities of Schizophrenic

Answer 55

1. Ventricles larger, so less space for brain cells 2. Prefrontal cortex damaged 3. Cell bodies are smaller in the hippocampus and prefrontal cortex 4. Less lateralisation than most people