The biological theory of schizophrenia

Question 1

the biological theories aim

Answer 1

explain schizophrenia by looking at the biological factors behind it

Question 2

What are the two biological explanations for schizophrenia ?

Answer 2

• Neurotransmitters can cause schizophrenia as there is an imbalance in diff parts of the brain
• brain dysfunction can cause schizophrenia if part of brain isn’t working properly

Question 3

explain the dopamine hypothesis

Answer 3

Too much neurotransmitters in the brains of schizophrenics, dopamine is produced by everyone and links to behaviour such as movement, mood , perception and attention. Too much dopamine = movements become erratic, people experience delusions or hallucinations . Research shows that the messages from dopaminergic neurons
that transmit dopamine fire too easily or too often, which can lead to many of the
symptoms of schizophrenia. People with schizophrenia seem to have unusually
high numbers of dopamine (D2) receptors on certain neurons, resulting in more
dopamine binding and therefore more neurons firing across synapses. This
could explain why people with schizophrenia may believe, hear or see something that does not exist.

Question 4

How does dopamine affect brain function ?

Answer 4

• PFC = not enough dopamine to support normal cognitive functioning
  Rest of brain = too much dopamine = too much info passed through synapses = excess in normal functions
  both can lead to clinical characteristics of schizophrenia e.g. rest of brain with too much dopamine -> too many thoughts = thoughts disturbances
  PFC -> too little dopamine = negative symptoms

Question 5

Explain the brain dysfunction theory

Answer 5

• Tests have shown that in people with schizophrenia, blood flow is lower in
  the frontal cortex region of the brain, and this area is less frequently activated
  when certain tasks are carried out. There is also some evidence that this part
  of the brain is smaller in volume. The prefrontal cortex, which acts like a
  ‘control centre for the brain’, appears to be defective. This may explain why
  people with schizophrenia lose control over their psychological functioning,
  such as planning ahead, being organised and making judgements. The
  temporal lobes are also lower in volume in people with schizophrenia. This
  is mainly due to a lack of grey matter in this part of the brain.
  The hippocampus, which has a role in formation of memories and
  the emotions that go with them, is smaller in volume in people with
  schizophrenia. Research shows that in general the more severe the disorder
  is, the more deflated this part of the brain is.

Question 6

What have psychologists argued to ?

Answer 6

• even though the effects may not be seen until many
  years later, some of this neurological damage in people with schizophrenia may
  occur before they are born, when their brain is exposed to an infection whilst still developing in the womb.

Question 7

State 2 criticisms of the theory

Answer 7

• By only focusing on nature, the theory ignores the effect of nurture
  on the development of schizophrenia. Even if evidence shows that
  the brains of people with schizophrenia look and work differently, this is not
  enough to cause the disorder by itself. The brain still needs to interact with
  what is happening in the environment to be able to produce symptoms like
  hallucinations, delusions and disorganised speech.
• It is possible that brain dysfunction is an effect of schizophrenia,
  not its cause. Because a lot of evidence comes from investigating the
  brain using post mortems or scans after the diagnosis is made, researchers
  cannot be sure what came first. Brain function and brain structure may
  change after something else has triggered the disorder. In other words, brain
  dysfunction is like a symptom.

Question 8

State 3 criticisms of the theory

Answer 8

• Critics say that the biological theory is too deterministic.
  Schizophrenia may not be completely controlled by what is happening
  in the brain. People may choose to let their symptoms take over rather
  than trying to mentally control them. Critics say that it is pessimistic
  to see people with schizophrenia as having no free will. Is the biological
  theory really suggesting that people with schizophrenia cannot control
  their disorder at all? Saying they cannot control their disorder is quite
  pessimistic.
  Critics say that the biological theory is too reductionist. They
  argue that it is too simplistic to try to explain such a complex disorder
  by just looking at a part of the brain or one neurochemical. A number
  different psychological factors may be working together to cause
  schizophrenia to occur rather than reducing it to one biological cause.
  For some psychologists, ‘schizophrenia’ is too broad a label that
  covers a diversity of symptoms. If this is true, it may not be realistic to
  look for a biological cause for something that may be partially constructed
  by society.