1. The Biological Explanations of Schizophrenia 1. Genetics 2. Biochemistry 3. Evolutionary Theory

2. 2. Biochemistry Dopamine Hypothesis

3. Biochemical Factors Dopamine hypothesis Post-mortems and PET scans have shown that people with schizophrenia have abnormally high levels of the neurotransmitter dopamine.

4. These findings have led to the development of the dopamine hypothesis which states that synapses that use dopamine as neurotransmitter are overactive in the brains of people with schizophrenia. Antipsychotic drugs reduce the symptoms of schizophrenia by blocking dopamine receptors.

5. Long answer - Dopamine Hypothesis People with schizophrenia have abnormally high levels of the neurotransmitter dopamine. This ‘dopamine hypothesis’ states that synapses that use dopamine are overactive in the brains of people with schizophrenia. Antipsychotic drugs reduce the symptoms of schizophrenia by blocking dopamine receptors

6. BRAIN Revision Clip 1 Clip 2 Clip 3  Neurotransmitters  Neurons + Synapses  Dopamine Hypothesis Clip 3 Clip cocaine

7. Dopamine Hypothesis Support  Antipsychotic drugs reduce the symptoms of schizophrenia by blocking dopamine receptors. This suggests that it is the overactive dopamine receptors causing the symptoms (Davison & Neale 2000)

8. Dopamine Hypothesis  Drugs like amphetamines which increase dopamine function can sometimes cause schizophrenia like symptoms in people without schizophrenia (Jackson 1986)

9. Dopamine Hypothesis  Evidence against...  Antipsychotic drugs only work on the positive symptoms of schizophrenia e.g. hallucinations. This means that increased dopamine functions does not explain negative symptoms like social withdrawal (Lavender 2000)

10. Dopamine Hypothesis Evidence against...  The link with dopamine is correlational so it does not show cause and effect. It may be that increased dopamine function is a symptom of schizophrenia rather than a cause of it (Davis 1978)

11. Other Neurological Factors Abnormal brain structure  Abnormal brain structure caused abnormal development could be the cause of schizophrenia

12. PET scans

13. Abnormal brain structure  Evidence for...  Johnstone et al (1976) compared the size of the ventricles (hollow spaces) in schizophrenics brains with non-schizophrenics’ brains.  They found that people with schizophrenia had enlarged ventricles which would suggest that schizophrenia is linked to a loss of brain tissue.

14. Abnormal brain structure  Evidence for...  Buchsbaum (1990) carried out MRI scans on schizophrenics’ brains and found abnormalities in the prefrontal cortex.

15. Abnormal brain structure  Evidence against......  Non-schizophrenics can also have enlarged ventricles which would go against Johnstone’s evidence.  These findings are correlational so they do not show cause and effect. It may be that abnormal brain structure is a symptom of schizophrenia rather than a cause of it.

16. 3. Evolutionary Theory ‘Group Splitting Hypothesis’

17. EVOLUTIONARY THEORY  Steve and Price (2000) suggested that schizophrenia is an adaption whose function is to facilitate group splitting this is known as “group splitting hypothesis.”

18. “Group Splitting Hypothesis.” This is how it works..  As the size of the group increases more eyes and brains are available to watch for predators and find food. However beyond a certain size, negative effects begin to out weight the advantages. Because there are more mouths to feed the share for each person is therefore reduced.

19. “Group Splitting Hypothesis.”  This means the group must travel greater distances to find a sufficient quantity as travel increases energy used increases risk from predator’s increases.  Consequently as the group grows through reproduction and from outsiders optimum size exceeded so fission (group splitting) occurs.

20. “Group Splitting Hypothesis.”  This is achieved by the formation of a sub group under a charismatic leader who because of their psychosis can separate themselves from the dogma of the main group and create a new community with a new world ‘view !’

21. “Group Splitting Hypothesis.”  Steven and Price suggest that symptoms of a schizoid personality (mood changes, delusions of grandeur etc) would have induced others; already feeling disconnected to adverse conditions because of the size of the group, to follow and form a new community. Such as found in leaders like Adolph Hitler and Jim Jones.

22. Adolph HitlerJim Jones.

23. Evaluation  Polimeni and Reiss (2002) propose schizophrenia is linked to Shamanism {a central charismatic figure in a tribal community}. This is frequently associated with supernatural qualities, ability to speak to spirits, perform magic.

24. Evaluation  Schizophrenia may have enhanced a Shaman’s ability to perform religious ceremonies such as universally observed in all cultures

25. Evaluation  Brewerton (1994) religious based experiences are common in schizophrenia. Rather than splitting groups they argue that schizophrenic symptoms may reflect an ancient and important form of behavioural specialization.

26. Now …Question time

27. Essay question  This question could appear as follows:  Describe one biological explanation for schizophrenia (5 marks)  Evaluate this explanation (10 marks)  (2) Describe one psychological explanation for schizophrenia (4 marks)  (3) Evaluate the biological and psychological explanations described in questions (1) and (2) (16 marks).

28. Easter question Critically consider one biological explanation of schizophrenia (5 + 10 marks) 1.5 pages of A4 paper only !!

29. Plan A01 – ½ page  Briefly outline your chosen explanation  Describe theory behind it  Use research names as evidence A02 – 1 page  Evaluate explanation  4 points needed  Named support/ weaknesses

30. PEER MARKING

31. Marking scheme MarksContent 5 Accurate & detailed, sound knowledge & understanding. Appropriate selection of research 4 Generally accurate but less detailed. Some evidence of correct selection of research. 2-3 Basic description lacking detail and muddled. Presentation of material is unclear. 1 Very brief or flawed descriptions with little knowledge shown. Selection /presentation is weak/unclear. 0No creditworthy material presented Definition of schizophrenia Describe biochemical factors -Dopamine hypothesis (Gross, 2010) -Action of drugs -Post mortems/PET Scans (Iverson 1979)

32. Marking Scheme A02 3 x Research support – used to back up points made 1 x IDA – integrated into discussion e.g. nature versus nurture 2 x Research method points (e.g. reliability, validity, reductionism, etc) Your points = Connected PEE used to explain points Use scientific language - e.g. “supported by,” “criticised by,” Nature vs Nurture debate Criticism 1.Reliability -Non- schizophrenics have high levels of dopamine (Jackson 1986) 2.Reductionist -Only works on positive symptoms doesn’t work on negative (Bentall 1990) 3.Dopamine is symptom rather than cause (Lloyd 1984 ) Support 4. Drugs block dopamine receptors (Davison & Neale 2000)

33. MarksContent Tickbox 10 Correct selection of material to answer the question. Knowledgeable discussion with strengths/weaknesses. Broad range of issues, including research methods. Language is scientific, clear and uses specialist terms. Points are linked together and some are supported by relevant research. Grammar/punctuation is good. 7-9 Research is not always used effectively to highlight points. Discussion is reasonably clear with good expression of ideas/concepts. Some errors in grammar, punctuation but clearly written. 4-6 Basic discussion with limited evaluation of research. Poor use of research support. Few specialist terms. Errors in grammar, punctuation, spelling. 2-3 Very basic discussion, few examples of research support for points made. Some points are vaguely described, presentation is unclear, confusing to read. 0No evaluation/discussion presented

34. Grades A- 12 B- 10 C- 9 D- 7 E- 6 U