Mental Health: The medical model

Question 1

According to the medical model, what is mental illness caused by?

Answer 1

Physical factors - brain & biology.

Question 2

What are the 3 main focus points within the medical model?

Answer 2

1- Genetic inheritance
2- Abnormal brain chemistry (bio-chemical)
3- Abnormal brain structures

Question 3

Definition of genetic inheritance

Overview

Answer 3

The idea that we may inherit mental illness or at least at susceptibility to develop it.

E.g., schizophrenia = high concordance rates between identical twins.

Question 4

Definition of abnormal brain chemistry (/biochemical)

Overview

Answer 4

The idea that our levels of hormones and neurotransmitters in the brain may cause mental illness.

E.g., monoamine oxidase, dopamine & serotonin.

Question 5

Definition of abnormal brain structures

Overview

Answer 5

The idea that the brain’s structure may be altered in individuals experiencing mental illness.

E.g., schizophrenia = enlarged spaces in their brain
-> suggesting shrinkage of brain tissue around these areas.

Question 6

Synapse

Answer 6

Tiny gaps between neurons, where messages move from one neuron to another as chemical or electrical signals.

Question 7

Neurons

Answer 7

Nerve cells

Question 8

What does the biochemical explanation believe behaviour relies on?

Answer 8

All of our behaviour relies on neurons (nerve cells) communicating with one another.

EXTENSION:

Electrical impulses and chemical signals carry messages across different parts of the brain and between the brain and the rest of the nervous system.

Question 9

What are neurotransmitters?

Answer 9

Chemicals which allow the transmission of signals from one neuron to the receptors in the next neuron across synapses.

Question 10

Give examples of neurotransmitters

Answer 10

1- Serotonin
2- Dopamine
3- Norepinephrine (noradrenaline)

Question 11

What is dopamine?

Answer 11

A neurotransmitter mainly involved in controlling movement and aiding the flow of information to the front of the brain, which is linked to thought and emotion.

Question 12

State 6 things that Dopamine is involved with (e.g., activities / behaviours).

Answer 12

1- Focus
2- Concentration
3- Memory
4- Sleep
5- Mood
6- Motivation

Question 13

What does having LOW LEVELS of dopamine mean / result in?

(Dopamine hypothesis)

Answer 13

Parkinson’s disease.

-> A disorder that affects a person’s ability to move as they want to, resulting in stiffness, tremors or shaking and other symptoms.

Question 14

What does having HIGH LEVELS of dopamine mean / result in?

(Dopamine hypothesis)

Answer 14

Schizophrenia.

-> Caused by an overactive dopamine system in the brain.

Question 15

What is the dopamine hypothesis?

(/ what does it suggest?)

Answer 15

Too much dopamine may lead to the overstimulation of cells

AND explain in particular, the positive symptoms of schizophrenia.
-> E.g., hallucinations, delusions, racing / confused thoughts.

Question 16

Evidence FOR the dopamine hypothesis

Answer 16

-> Dopamine markers suggest high levels relate to schizophrenia.

• Observations of the dopamine-blocking drugs.
• Some schizophrenia symptoms may be triggered when certain areas of the brain have high levels of dopamine and other areas have lower levels.

Question 17

Evidence AGAINST the dopamine hypothesis

Answer 17

-> Reductionist = situational factors could be associated with dopamine / brain structure / damage.
- Drugs can also influence dopamine, genetics, serotonin and other neurochemicals.

• Effects of dopamine release have rarely been explained.
  (E.g., movement, arousal, attention, stress).
• Some people with schizophrenia had typical levels of dopamine in cerebrospinal fluid as opposed to elevated levels.
• Researchers found that drugs which reduce schizophrenia symptoms do not necessarily reduce dopamine levels.

Question 18

How do we measure neurochemicals?

Answer 18

Measurement of dopamine DIRECTLY is NOT POSSIBLE.

-> We rely on measurement of a dopamine marker.

-> Dopamine markers measure the levels of dopamine in the brain INDIRECTLY.

-> This may lead to problems with the accuracy of the researcher’s measurements, and the validity (as other variables may influence the marker).

Question 19

What are dopamine markers?

(& Why may they lead to problems?)

Answer 19

Dopamine markers measure the levels of dopamine in the brain INDIRECTLY.

-> This may lead to problems with the accuracy of the researcher’s measurements, and the validity (as other variables may influence the marker).

Question 20

What do genetics study?

Answer 20

The study of heredity

Question 21

Heredity definition

Answer 21

Studies:

How the characteristics of living things are transmitted from one generation to the next.

Question 22

Diathesis stress theory

(Detailed)

Answer 22

-> Inherited susceptibility (diathesis) which develops if an individual is exposed to difficult environmental conditions (stress).

-> The greater the vulnerability, the less stress needed to produce a trigger.

-> Having a diathesis causes increased risk, but does not necessarily mean an individual will develop schizophrenia.

-> The theory shows the interaction between biological, psychological and environmental factors.

-> Stressors range from major / traumatic (e.g., divorce) to mundane (E.g., stuck in traffic).

Question 23

Diathesis stress theory

(Simple)

Answer 23

Diathesis + stress = illness

Question 24

Diathesis definition

Answer 24

Inherited susceptibility

Develops: individual is exposed to difficult environmental conditions (stress).

Question 25

What is one (/2) way(s) to investigate the role of genetics?

& why?

Answer 25

Twin and adoption studies.

Twin -> comparison of monozygotic (identical) and dizygotic (non-identical)

Why?
They isolate biology and the environment as causes / explanation of e.g., schizophrenia.

Question 26

Concordance rate definition

Answer 26

The extent to which (2) family members are similar.

(When studying 2 family members).

• Unless there is 100% of concordance, there are other factors affecting.

Question 27

Discordant rate definition

Answer 27

The extent to which (2) family members are dissimilar.

Question 28

General overview of research by:

Gottesman and Shields (1976)

Answer 28

Showed:
-> when looking at the development of schizophrenia, twin studies consistently find HIGHER concordance rate in MONOZYGOTIC twins than dizygotic twins.

Suggests:
-> Evidence of a genetic predisposition / cause of schizophrenia.

However:
-> As concordance rates are NOT 100%, there must be some interaction with the environment.

Not clear:
-> Whether one or many genes are responsible for predisposing a person to schizophrenia.

Question 29

Why has the advancements in medical screening technology helped the ‘brain abnormality’ explanation?

Answer 29

It has allowed psychologists to study the structures of the brain and look for differences in this with an without mental illness.

Question 30

Brief sentence outlining:

Brown et al 1986

(What it showed & thus suggests).

Answer 30

(Early studies relied on studying the brain post-mortem).

Showed that the brains of those with schizophrenia were 6% lighter and had larger lateral ventricles.

Suggests:
-> The increase in ventricle must mean a decrease in grey matter somewhere in the brain (e.g., temporal lobe).

Question 31

What are the lateral ventricles?

Answer 31

2 curved openings (shaped like a horseshoe)
located deep within the top section of the brain
that provide a pathway for cerebrospinal fluid.

(1 on each side of the brain).

Question 32

Cerebrospinal fluid definiton

Answer 32

Cushiony fluid that protects the brain and spine from trauma.

Question 33

Give examples of scanning technology

Answer 33

1- MRI Scans
2- PET scans

Question 34

What are MRI scans?

Answer 34

Magnetic resonance imaging.

Description:

-> Patient lies in a round tunnel surrounded by a large magnet which generates a powerful magnetic field.

-> Hundreds of measurements are converted into an anatomical image of the brain structure.

Question 35

Strength(s) of MRI scans

Answer 35

-> Provides detailed view of the brain in different dimensions.

-> Safe, painless, non-invasive.

Question 36

Weakness(es) of MRI scans

Answer 36

-> Expensive

-> Cannot be used with patients with pacemakers or metallic devices.

Question 37

What are PET scans?

Answer 37

Positron Emission Tomography.

Description:
Patient is given radioactive glucose which then reaches active areas of brain and can be ‘seen’ in colour as active in scan pictures.

Question 38

Strength(s) of PET scans

Answer 38

-> Can show where activity is occurring and can be used for diagnosis.

Question 39

Weakness(es) of PET scans

Answer 39

-> Expensive to use

-> Due to radioactive substances, cannot be used too frequently (more than twice could cause risk to patient).

Question 40

What do the ENLARGED VENTRICLES do?

& link to schizophrenia

Answer 40

Role:
-> Provide a pathway for cerebrospinal fluid.

-> Usually correlated with decreased cortical grey matter volumes.

Link:
-> The ventricles of patients with schizophrenia are approx. 130% the size of normal controls.

Question 41

What does the HIPPOCAMPUS do?

& link to schizophrenia

Answer 41

Role:
-> Mediates learning and memory function.

Link:
-> Disorganised speech (e.g., frequent derailment or incoherence).

Question 42

What does the THALAMUS do?

& link to schizophrenia

Answer 42

Role:
-> Involved in sensory and motor signal relay (all sensory processes except smell).

-> Plays a role in controlling the motor system of the brain responsible for voluntary body movement and coordination.

Link:
-> Grossly disorganised or catatonic behaviour.

Question 43

What does the following cause in the brain?

‘Reduction in cortical volume and thickness in the frontal and temporal lobes’

& link to schizophrenia

Answer 43

Role:
-> Reduction in volume / thickness = correlated negatively with age

-> Frontal lobes = involved with decision-making, problem solving, and planning.

-> Temporal lobes = involved with memory, emotion, hearing, and language.

Link:
-> Negative symptoms (i.e., diminished emotional expression or volition).

-> Grossly disorganised or catatonic behaviour.

Question 44

Application: biological treatment of one disorder.

What are the 3 suggested causes of mental illness according to the medical model?

& which of the 3 causes are we MOST able to correct / treat?

Answer 44

Causes:
1- Genes / genetics
2- Brain abnormality (structure)
3- Biochemical

Most able to correct:
Biochemical

Question 45

What are biological treatments available for schizophrenia?

Answer 45

1- Drugs (chemotherapy)
2- ECT (Electro-Convulsive Therapy)
3- Psychosurgery (brain surgery)

Question 46

Suggest how biological treatment can be used to treat one specific disorder.

5

Answer 46

Disorder = Schizophrenia.

-> When under assumption MI is caused by the biochemical explanation of MI from the medical model.

Examples:
-> Drugs (chemotherapy)
-> ECT (Electro-convulsive therapy)
-> Psychosurgery (brain surgery)

Drugs (detailed):
-> E.g., antipsychotics
-> Used to treat schizophrenia: reduce the symptoms by inhibiting the effect of dopamine.
-> (bc. high dopamine = schizophrenia).
-> Most common = quick & effective, but have negative side effects.

Question 47

Discuss the nature / nurture debate in relation to the biological explanation of mental illness

10

Answer 47

Debate:
Belief that behaviour is due to either genetics / disposition (nature), or individual’s upbringing / life experiences / development (nurture).

Link:
-> Supports the nature side -biological explanation (medical model) encompasses the genetic explanation of mental illness

Nature because:
Genetic-> Inherit mental illness / have as susceptibility to develop it.
-> E.g., schizophrenia = high concordance rates between identical twins.

Biochemical -> focuses on levels of neurotransmitters causes MI. -> Gives evidence that biological make-up is responsible, not development.

Nurture because:
-> Also consists of the biochemical explanation & brain abnormality explanation.

Brain abnormality -> focuses on how brain structure affects MI. -> develop after birth e.g., trauma.

Biochemical -> shows that high / low levels of neurotransmitters may cause MI -> developed over time.

Question 48

Serotonin

Answer 48

Monoamine neurotransmitter.

A chemical that carries messages between nerve cells in the brain and throughout the body.

Role:
-> mood
-> sleep
-> digestion
-> Wound healing
-> bone health
-> blood clotting

Question 49

DETAILED

Biochemical explanation for mental illness

Answer 49

One of the main 3 points within the medical model.

It focusses on the balance of chemicals in the brain, specifically CHEMICAL IMBALANCE THEORY.

It states that all our behaviour relies on NEURONS communicating with one another.

Mental illness is believed to occur when the neurotransmitters, which are the chemicals which allow the transmission of signals from one neuron to the receptors in the next neuron across synapses does not work.

Examples of monoamine neurotransmitters are SEROTONIN, DOPAMINE, cortisol, and NORADRENALINE.

Treatment methods include drugs (chemotherapy), ECT, and psychosery.

EXAMPLES OF DRUGS:

-> Schizophrenia = high levels of dopamine = antipsychotics.

-> Depression = low levels of serotonin / high levels of cortisol / result of chemotherapy (causes decrease of oestrogen: influences serotonin) e.g., MAOI’s and SSRI’s (selective serotonin reuptake inhibitors) which cause an increase in the amount of serotonin.
= antidepressants

Question 50

DETAILED

Genetic explanation for mental illness

Answer 50

Proposes that inherited genes can be attributed to mental illness and can increase an individual’s susceptibility to developing a certain disorder (e.g., schizophrenia).

Gottesman & Shield’s adoption and twin studies (1972 & 76) have shown that when looking at the development of schizophrenia, these studies find higher concordance rates in monozygotic twins than between dizygotic twins.

However, concordance rates are not 100%, and therefore, there must be some interaction with the environment and nurture factors involved as part of the nature vs nurture debate.

The key study by Gottesman et al. (2010) investigates whether genetic transference from the parents is the cause of a child developing (severe) psychiatric disorders.

It may be put forward that evolutionary theory supports the genetic explanation as they both outline the importance of heredity in the development of a species such as the development of mental illness.

Embryo manipulation also coincides with the genetic explanation as usually when an embryo is altered, it is the genes that are changed by inserting the desired material into the sperm and or egg cells using advanced gene-editing technology.

Overall, it is clear that a person’s genes have a large influence over susceptibility to mental illness, but these genes would later need to interact with environmental factors to produce mental illness in an individual (diathesis stress theory).

Question 51

DETAILED

Brain abnormality explanation for mental illness

Answer 51

Brain abnormalities can be used as an explanation for mental illness as medical screening technology has allowed psychologists to study structures of the brain.

For example, by using scans such as MRI and PET scans which allow psychologists to pinpoint brain damage that could cause mental illnesses.

Neuroscience and neuropsychology are used to study the brain, even during post mortem investigations.

Brown et al. found from studying the brain of those with schizophrenia that they were 6% larger and had larger lateral ventricles.

There is evidence that hippocampal volume, amygdala, pre-frontal cortex, and ventricular enlargement can be linked to symptoms of schizophrenia or other mental disorders.

For example, a patient that has low activity in the amygdala may be more prone to symptoms of psychopathy or sociopathy, or a patient that has low hippocampus functionality may have schizophrenia symptoms such as disorganised speech, incoherence and derailment.