What causes schizophrenia? A wide range of views offered based on CIE A2 syllabus

1. Schizophrenia:
Etiology
E. KENT ROGERS

2. Physiological
 Almost all mental health workers now agree that the cause of
schizophrenia has a strong biological element. There is a robust and
growing body of evidence that supports this. In the next few slides, we’ll
be looking at these:
1. Stem cell research
2. Specific gene abnormalities Brain structure abnormalities
3. Protein abnormalities found in the blood of schizophrenia.
4. Family patterns, including identical twin studies
5. Successful treatment with medication
6. Neurotransmitter abnormalities
7. Brain anatomy abnormalities
8. Brain wiring abnormalities
9. In utero Virus

3. Stem Cell Research
 Stem cells taken from schizophrenics and trained to
become neurons produce more dopamine than that
of controls (Vivian Hook, 2014)
 Argument for Biological Cause: Since stem cells have
not had any social or other experiences, the problem
must be based in genes.
 Counter-argument: Epigenetics
 Counter-Counter-Argument: Regardless of how genes
came to be as they are, they are still the cause

4. Abnormal Genes Identified
 Gene ZNF804a implicated schizophrenia Girgenti, et al. (2012)
 Hovatta et al. located likely genes associated with schizophrenita
(1999)
(Just write: “Girgenti et al. and Hovatta et al. and others have found
genetic abnormalityes associated with schizophrenia”
Counter-argument: Can’t be genes alone since identical twins
(monozygotic twins) only have a fifty percent chance of both
having schizophrenia

5. Protein Blood Screenings
 These blood tests check protein levels and types. Schizophrenics
have differences from normal population. These screenings are over
80% accurate in diagnosing schizophrenia. (Bahn et al.)
 Argument: A biological abnormality suggests biological cause.
 Counter-argument: Experience and behavior is known to alter how
biology functions

6. Family Patterns
 The closer the relationship, the more likely both members are to
have schizophrenia. (See textbook for specifics).
 Argument: This suggests genetic causes.
 Counter-argument: If genes were alone responsible, monozygotic
twins of schizophrenics would have a 100% chance of developing
schizophrenia, not 50%, the actual rate. Also, being married to a
schizophrenic slightly increases the chance of a partner having it.
This points to social influence, which also occurs in families.

7. Medications
 In 1951, phenothiazines were developed by Lobrorit. They reduced
psychotic symptoms.
 These same drugs caused muscle tremors as seen in Parkinson’s disease.
 It was known that Parkinson’s is caused by low levels of dopamine in
some areas of the brain. Therefore, perhaps the antipsychotics were
lowering dopamine which would mean high levels of dopamine might
cause the symptoms of schizophrenia.
 And too much L-dopa, the medicine that treats Parkinson’s, causes
schizophrenia-like psychosis.
 Also, amphetamines greatly amplify dopamine and too much of these
also cause schizophrenia-like psychosis.

8. Medications continued.
 Therefore, it is clear that too much dopamine in certain
areas of the brain cause symptoms of schizophrenia. This
supports a biological etiology.
 Counter-argument…same as above.
 *NOTE: it should be noted that new “atypical”
antipsychotics often work better than the phenothiazines.
These new drugs work on other neurotransmitters, so
dopamine doesn’t seem to be the ONLY factor in
schizophrenic psychosis.

9. Neurotransmitter Abnormalities
 Supporting the stem cell research and the deductions based on
effective medicate, certain areas of schizophrenic brains have
shown to have elevated levels of dopamine.

10. Brain Anatomy
 Schizophrenics also have smaller brains
 Schizophrenics also have less grey matter
 Schizophrenic brains have enlarged ventricles, the spaces of fluid in
the brain. This means there is less brain mass surrounding the
ventricles.
 In other words, there is actual brain damage.
 Finally, schizophrenic brains have higher density of dopamine
receptors.

11. Brain Wiring/Functioning
 fMRI scans have shown schizophrenic brains to function in different
ways.

12. In Utero Viral Infections
 It has been shown that children of mothers who had influenza
during the second trimester have elevated risk of having
schizophrenia

13. Evidence for Environmental Causes
 As stated above, the fact that identical twins only have a 50%
chance of having schizophrenia if their twin has it shows that there
must be something more than genetics alone. There must be an
environmental factor.
 It is generally believed to be stress.

14. Cognitive View continued: FRITH
(1992)
 FRITH (1992) argued that a number of schizophrenic symptoms can
be explained by deficits in Theory of Mind, a two step processes
involved in empathy:
1. Inference: Recognizing how someone is feeling by non-verbal cues
2. Attribution: Understanding why someone is feeling the way they do.

15. Cognitive: FRITH
 Firth did a test involving a story and cartoons, similar to Nelson. Each
story involved a person being deceptive.
 Patients and controls were then asked questions that required an
understanding of what the characters were thinking and feeling.
 Those with negative symptoms and paranoid delusions did worse
than controls with Theory of Mind questions.

16. FRITH CONTINUED
 Frith argued that lack of Theory of Mind accounts for the following
schizophrenic symptoms:
 Delusions: They can’t understand that their own ideas are not
necessarily true.
 Paranoia: They can’t interpret other’s intentions and when others
don’t agree with their own experiences (hallucinations) they
become paranoid that others are plotting.
 Break down of social relationships: without theory of mind,
communicating become confusing and so they withdraw.

17. Uniting the Biological and
Environmental Theories
The Diathesis-Stress Hypothesis
 Most mental health theorists, scientists and practitioners
believe in the diathesis-stress hypothesis.
 Genetic factors load the gun with the bullet. Stress pulls
the trigger. If there is not enough stress, the bullet is not
released (i.e., schizophrenia does not occur)

18. So we might think of it this way
(though this is not for sure)…
 Genetic abnormality PLUS STRESS leads to…
 Altered protein synthesis and altered neurotransmitter, especially dopamine,
levels. This leads to…
 Deterioration of brain functioning and this probably leads to…
 Hallucinations and break down in theory of mind which leads to…
 Delusions, paranoia and social withdrawal. Which leads to
 Furthers psychosis and dysfunction of the brain. This in turn leads to…
 Diminished brain size, grey matter etc.