The biological model assumes that psychological illnesses have a physical cause in the brain due to biological dysfunctions, genetics, toxins, infections, or stress. Possible biological causes of abnormal behavior include imbalances of neurotransmitters or hormones, structural damage or abnormalities in the brain, and genetic factors associated with schizophrenia. While studies have found associations between psychological disturbances and biological changes, it is difficult to determine whether biological changes cause or result from psychological symptoms. The biological model also faces issues regarding evidence, patient roles, and social stigma.

1. The Biological Model
Main assumptions:
Psychological illnesses have a PHYSICAL
cause.
Abnormal behaviour, thinking and emotion are
caused by biological dysfunctions
Understanding mental illness involves
understanding what went wrong with the
brain
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2. The Biological Model
Possible cause of abnormal behaviour
Genetics – inherited developmental abnormality
Toxicity – chemical poisoning from e.g. drugs or
environmental toxins
Infection/disease – causing chemical or
structural damage to the brain
Stress – causing abnormal hormonal effects in
the long term
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3. Genetics and schizophrenia

4. The Biological Model
Possible causes of abnormal behaviour:
– Biochemistry – an imbalance of certain
neurotransmitters or hormones might cause
parts of the brain to malfunction
– Structural damage or abnormality – if the
structure of the brain is damaged or
improperly formed then thinking, emotion and
behaviour may change
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5. Example – Clive Wearing

6. Brain Abnormality (Structure)
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7. Brain Abnormality (Structure)
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8. Brain Abnormality (Functioning)
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9. The Biomedical Model
Issues for evaluation:
– The evidence
– The patient role
– Blame and stigma
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10. The Biomedical Model
Evidence
– Plenty of studies have found that
psychological disturbance is associated with
biological changes (e.g. in neurotransmitters
& hormones)
However…
– It is often impossible to tell whether such
changes are a cause or an effect of the
psychological symptoms
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11. The Biomedical Model
The patient role
– The biomedical model offers people a role
and treatments they are familiar with, and are
often happy to go along with
However…
– It encourages them to become passive and
dependent and to hand over control of their
lives to the expert – this might not actually be
good for them.
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12. The Biomedical Model
Blame & stigma
– Biomedical processes are assumed to be
beyond patient’s control; they are not blamed
for their predicament or behaviour
However…
– Critics (e.g. Szasz, Laing) argue that society
isolates and stigmatises the mentally
‘ill’, which is just as bad
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