lecture 6- biomedical model of mental health

Question 1

The biomedical model overview

Answer 1

• Suggests there is no meaningful distinction between mental and physical diseases.
  
  • Mental disorders reflect a disturbance of brain structure and/or function
    Puts more emphasis on medical treatment.

Question 2

Biological causes of mental health disorders

Answer 2

1) Neurotransmitters and hormones
2) Genetics
3) Developmental abnormalities
4) Physical deprivation
5) Neglect or stress
Toxic or infectious agents

Question 3

Neurotransmitter imbalance:

Answer 3

Altered production of neurotransmitters at synapses over or under-stimulates the target neuron.
The altered reuptake of neurotransmitters either increases or decreases concentration at synapses.
Alterations in neurotransmitter receptors so they are abnormally sensitive or insensitive.
- Psychotropic drugs used for anxiety, depression, OCD and schizophrenia influence synaptic transmission.
- They can:
○ Increase/decrease transmitter release
○ Increase/decrease transmitter reuptake
○ Stimulate or inhibit transmitter receptors

Question 4

Drugs and mental disorders:

Answer 4

Drug discovery can help to understand mechanisms of disease
Amine hypothesis of depression- antidepressants correct a chemical imbalance in the brain.
- In the 50’s, reserpine was used to treat high BP, but patients were becoming depressed or suicidal
The drug was found to depleting nerve cells of amine neurotransmitters like serotonin and dopamine

Question 5

iproniazid

Answer 5

In the late 50’s, iproniazid was developed with side-effects including euphoria, increased appetite and improved sleep, subsequently used to treat depression. Found to work by increasing amine neurotransmitters.
- Depression is caused by deficiency of amine neurotransmitters. Anti-depressants then correct the deficiency and all modern anti-depressants work this way.
- Most anti-depressants are serotonin-selective reuptake inhibitors, blocking the reuptake of serotonin increases its concentration at synapses in the brain

Question 6

Criticism of the amine hypothesis:

Answer 6

• Over simplification
  
  • Methodological problems such as small sample sizes and poor control of confounding variables
  • Inconsistent findings
    Problem with basing a theory of disease causation on the mechanism of a drug used to treat it

Question 7

Hormones and mental illnesses:

Answer 7

The endocrine system consists of glands that secrete hormones into the blood stream
- The pituitary gland in the brain is the master gland and controlled by the hypothalamus
Hypothalamic-pituitary-adrenal axis is over active in stress states.
- Leads to persistent elevation of the stress hormone cortisol in the blood stream
- And is implicated in several psychological disorders like depression and anxiety

Question 8

Genetics and mental illnesses:
chromosomal abnormalities-

Answer 8

chromosomal abnormalities- complete or partial duplications/deletations can result in down syndrome, intellectual disability and dementia
Single gene defects- abnormalities in particular genes or disease associated normal variants
Vulnerabilities to mental disorders are usually polygenic (influenced by multiple genes)
There is not a singe gene for a particular disorder

Question 9

Epigenetics

Answer 9

a person genetic code, fixed at birth, but genes can be switched on or off during life. Genes are silenced using molecular tags to parts of the DNA strand
- The pattern of gene methylation is influenced by the environment, including early life experiences, adverse life experiences can lead to epigenetic changes that influence risk of mental disorders in adulthood.
- Gene-environment interaction: behaviour isn’t exclusively determined by the genes that you inherit, psychiatric disease risk depends on genetic and environmental factors

Question 10

4 Types of biomedical model treatment

Answer 10

1) Transcranial magnetic stimulation
2)Insulin shock treatment
3) Frontal leukotomny
4)Electroconvulsive therapy (ECT)
5) Deep brain stimulation

Question 11

Transcrainal magnetic stimulation

Answer 11

uses an electromagnetic coil to deliver magnetic pulses to the brain.
○ More focused than ECT as it can be targeted to specific areas
○ Also used to treatment-resistant depression and anxiety.
○ TMS found effective for acute depression but not as good as ECT

Question 12

Insulin shock treatment:

Answer 12

○ Mainly for schizophrenia, used insulin to induce a coma
Risks of obesity, seizures, brain damage or death

Question 13

Frontal leukotomny:

Answer 13

○ Drilled a hole through the skulls- through the frontal lobe and placing a probe inside and moved it around
○ Resulted in induced brain damage
Then began to use the stick through the eye as a less invasive approach

Question 14

Electroconvulsive therapy (ECT)

Answer 14

○ Controlled induction of convulsive seizures under anaesthesia
○ Safe and effective in several disorders
○ Affects numerous neurochemical systems
But has a high relapse rate

Question 15

Deep brain stimulation

Answer 15

○ Over-activity of BA 25 in patients with severe drug resistant depression
○ Reduced metabolism and blood flow

Question 16

4 types of pharmological treatment

Answer 16

Selective serotonin reuptake inhibitor:
- Several types which act on different neurotransmitters and is found to be effective
- Side effects include nausea, nervousness, insomnia and sexual dysfunction
- Used in the treatment of other disorders as well.
- Only used in severe cases
Anxiolytics (SNRI)
- Used when self-help and CBT fails.
- Selective reuptake inhibitors, so that noradrenaline stays in the synaptic cleft for longer
Antipsychotics (neuroleptics)
- Treat psychotic disorders by blocking brains dopamine receptors
- Reduces delusions and hallucinations
- Can lead to weight gain, diabetes and reduced white blood cell counts
Mood stabilisers eg lithium
- Treat bipolar affective disorder
- Mechanism uncertain and there is a risk of toxicity but very effective
Can lead to thirst, weight gain, tremor and fatigue

Question 17

4 Advantages of Biomedical model:

Answer 17

1) Suggests a clear mechanism for most disorders
2) Particularly effective at delivering insights into disorders, with a cleared biological base
3) Drug treatment revolutionised patient care (more effective than other therapies)
Based on scientific methods

Question 18

6 Disadvantages of Biomedical model:

Answer 18

1) Assumes universality, there is not room in framework for social, psychological or behavioural dimensions
2) Reductionism- is psychology really just biology
3) Deacon 2013- biomedical claims mental disorders are brain diseases caused by organic cause yet scientists have not identified any of these organic causes
4) Claims psychotropic medication works by correcting neurotransmitter imbalance which causes mental disorder but there are not any evidence that mental disorders are caused by chemical imbalances
5) Claims biological psychiatry has made great progress in reducing societal burden of mental disorders but mental disorders have become increasingly chronic and severe
Assumes mental illness is caused by underlying biological factors but pharm logical interventions are rarely effective alone