The biological approach views mental disorders as medical conditions with physical causes, such as infections, biochemical imbalances, genetic factors, and neurological damage. Strengths include modern brain scanning technologies identifying biological abnormalities and some effective drug treatments. However, it is also reductionist by ignoring environmental influences, and drug treatments do not work for all disorders. The diathesis-stress model provides a more balanced view that both biological and environmental factors interact to cause psychopathology.

1. The biological approach
Psychopathology

2. Assumptions
 Mental disorders can be classified, diagnosed
and treated by the medical profession in the
same way as disease.
 The emphasis is on physiology as opposed to
behavioural, cognitive or affective difficulties
 Scientific research will eventually discover a
physical cause for all types of mental disorder

3. Infection.
 We are all familiar with the fact that
many physical illnesses are caused by
viruses or bacteria invading the body.
 It has been suggested that this may be
the cause of some psychological
abnormalities, but it is thought that there
are not many of these.

4. Example
 One particular example would be
general paresis, which is a disorder
that involves the patient becoming
increasingly forgetful and intellectually
impaired to their pre-morbid state. It is
known that this disorder is caused by an
infection due to syphilis, which is a
sexually transmitted disease.

5. Biochemical Factors
 Biochemical Factors.
 The brain operates by transmitting impulses from one
nerve cell to another via a chemical medium.
 These chemicals are called neurotransmitters and
are present in the central nervous system, and there
a number of different neurotransmitters that do
different ‘jobs’.
 Some abnormalities are thought to be related to
deficiencies, or increased levels, of particular
transmitters, which leads to chemical imbalances.

6. Biochemical Factors
 These chemical imbalances are thought to be
the cause of some psychological
abnormalities.
 Schizophrenia is an example of this – in
schizophrenia there is an increased level of
the neurotransmitter dopamine in the brain
(see handout)
 Serotonin is a brain chemical associated with
depression.

7. Genetic Factors
 Some psychological disorders are thought
to be caused, at least in part, by genetic
factors.
 This is where individuals within a family can
exhibit the same or related pathologies (they
have the same disorders).
 There has been a lot of research into this
field, particularly with discrete societies. Many
studies have looked at the Amish community
in the US, which has stood still for many
years.

8. Genetic Factors
 Amish people live a very particular lifestyle and they
do not marry outside of their community, it is
therefore an ‘opportune’ genetically related sample.
 It has been shown that in one particular Amish
community, depression is present in certain families
and is not present in others. This would suggest that
depression, or a vulnerability to exhibit depression, is
genetically caused, i.e. people sharing the same
gene pool, with the disorder, are more likely than
others to show the symptoms of depression.
Researchers suggest that there are genetic
markers, for some conditions as a result of this type
of study.

9. Twin studies
 Twin studies are used to investigate the role
of genetics.
 MZ twins – share 100% of genes
 DZ twins – share 50% of genes
 Psychologists look at the concordance rates
for abnormality i.e. what % of the twins both
have the same ‘abnormal’ condition.

10. Genetic Factors
 Twin studies have found a concordance rate
between MZ twins of around 80% for
schizophrenia.
 A concordance rate of around 47% has been
found for anxiety disorders.
 These studies are often used as evidence in
the nature-nurture debate.
 If genetics were wholly responsible for mental
illness what would the concordance rate be?

11. Diathesis stress theory
 Meehl (1962) and Rosenthal (1970) have
developed a theory called the diathesis-stress
theory, which states that the abnormality itself is not
inherited, but a predisposition (vulnerability) to
develop the illness is inherited (diathesis).
 The idea behind this is that if the predisposition for
depression say, is present in the family, then the
possibility of inheriting the illness is present but that it
will be life events and conditions that determine
whether it is developed or not (stress).

12. Diathesis stress
 The diathesis stress model emphasises
biological factors but also considers
environmental factors in the development of a
disorder.
 Therefore this represents an interaction
between nature and nurture and so is a likely
explanation.

13. Neurological Factors
 Damage to the nervous system,
especially the brain, can lead to difficulties of
normal functioning of the cortex.
 There are specific links between some mental
disorders and abnormalities of functioning of
the brain.
 These abnormalities can be biochemical or
structural. Alzheimer’s, a degenerative
disease causes cortical malfunctioning and
affects memory.

14. Neurological Factors
 Some types of depression are linked to abnormal
levels of neurotransmitters in the brain, which causes
cortical malfunction.
 There is also a suggestion that in bi-polar disorder
(manic depression psychosis) there is a defective
gene which produces a biochemical imbalance which
leads to extreme swings of mood, hence the mania
and depression combined.
 Thus we see interplay of both genetic and
biochemical factors, resulting a neurological disorder.

15. Evaluation of the approach
 This is the dominant approach in diagnosing
and treating abnormality.
 Psychiatrists qualify as medical doctors
before specialising in mental illness.

16. Evaluation of the approach +
 Modern techniques such as brain scans can
identify issues to do with the brain.
 Scans can show that people with depression
have low levels of serotonin and that
schizophrenia is linked to excess dopamine.
 Scans have also showed that people with
schizophrenia suffer a loss of brain tissue

17. Evaluation of the approach +
 Research has identified a genetic component
in disorders such as schizophrenia, bipolar
depression and some phobias.
 Drug treatments (based on the biological
approach) are effective at treating some
disorders.

18. Evaluation of the approach -
 This approach is very reductionist.
 This means that it has a very simple view of
psychopathology (caused by biological
factors) and so ignores any possible
environmental influences.
 For example, we know that depression is
linked to serotonin but life stressors also play
a part in depression.
 The diathesis stress model highlights how
biology interacts with environmental factors.

19. Evaluation of the approach -
 Although drug treatments can be effective
(and so provide evidence for a biological
basis) they do not work for all people and all
conditions.
 They are not so effective for conditions like
eating disorders and phobias.

20. Activity
 1. On your diagram of a person, represent
biological explanations for abnormality.
 Try to also include the strengths and
weaknesses of the approach.
 2. Cut out the key points from the sheet on
the biological approach and group them into:
 Descriptions of the approach
 Evaluation – strengths
 Evaluation – weaknesses