explanations of schizophrenia: explanation + evaluation

AO1: outline neurochemical explanation of schizophrenia 

- suggests an excess of dopamine ( a neurotransmitter) is involved in development of schizophrenia 

-based on 3 observations

1. phenothiazines- these are antipsychotic drugs used to treat schizophrenia(SZ). they reduce dopamine levels in the brain and reduce schizophrenic symptoms. This is taken to mean that high dopamine levels are related to SZ.

2.L-DOPA is a drug used to treat parkinsons disease. it increases levels of dopamine in the brain. In too high a dose, it can cause many schizophrenic symptoms. This again is taken to mean that high dopamine levels are related to SZ as increasing them creates schizophrenic symptoms.

3.Post-mortems performed of schizophrenics have shown unusually high dopamine levels especially in limbic system. 

AO2: evaluate neurochemical explanation of SZ 

1. Randrup et al: found that schizophrenic symptoms could be induced in rats when given amphetamines. the rats showed symptoms of disorganised behaviour ( continuous licking and sniffing). He found that the results could be reversed with antipsychotic drugs. 

2.Amphetamines and cocaine increase dopamine in the brain. if taken too much these substances can sause 'amphetamine psychosis' or 'cocaine psychosis'. symptoms of this are virtually indistinguishable from those of SZ.

3. Treatment aetiology fallacy: this means that the disorder is being explained by the drugs used to treat it. in this case , antipsychotic drugs decrease dopamine levels in the brain so it is assumed that high dopamine levels cause SZ. 

4. Cannot establish causation- post mortems cannot reval whether increased dopamine cases SZ or whether SZ interferes with dopamine metabolism.

AO1: outline genetic explanation of schizophrenia- suggests that some people are born with biological predisposition to SZ.

- universal general prevelance rate of SZ= 1%

- if one parent has SZ risk increases to 6%

- if identical twin has SZ risk imcreases to 48%

- if non identical twin has SZ risk increases to 17%

- there are a number of genes that contribute to susceptibility of SZ: weinberger     estimated that number of gene variations linked to SZ was 10, the more of            these gene variations a person has, the higher the risk of getting SZ.

- If COMT gene is abnormal it effectively depletes frontal lobes of dopamine which     can unleash hallucinations and impair the brains reality check. 

AO2: evaluate genetic explanation of schizophrenia 

- kety et al's copenhagen high risk study: identified 207 offspring of diagnosed schizophrenic mothers and 104 offspring of 'healthy' mothers. children aged between 10 and 18 years at start of study and were matched on age, gender, parental socio-economical status and urban/rural residence. follow up of children conducted when mean age was 42. Results showed that 16% of 'schizophrenic' group has developed SZ compared to 1.9% of control group.--> supports familial link to SZ

-Tienari's finnish addoption study: identified 112 'adopted away' offspring of diagnosed schizophrenic mothers and a matched control group of 135 'adopted away' offspring of mothers who had not been diagnosed with any mental disorder. adoptees were aged between 5-7 at start of study and had all ben separated by their mothers at 4 years old. results found that 7% of experiemntal group developed SZ compared to 1.5% of control group.

AO1: outline the psychodynamic approach to schizophrenia - 

- freud suggested that schizophrenia is an infantile state of being brought about by a desire to escape the harsh realities of an uncaring world. 

- he said that cold , hostile parenting can play a big role in development of SZ: the harsh reality of a difficult life creates a desire to escape the conscious awareness of these difficult issues.

- regression into a childlike pre-ego state is used as a coping mechanism. primary narcisism ( early oral stage of development before ego has separated itself from id) is a stage where reality ceases to exist and id rules. 

- symptoms of SZ related to particualr parts of regression : neologisms, echolalia and echopraxia all childlike acts brought on by infantile state, delusions of grandeur represent selfish personality of pre-ego (id), halluciantions = ego trying to regain control over psyche 

AO2 : evaulate the psychodynamic approach to schizophrenia

- oltmanns et al found that parents with schizophreic offspring do behave differently to other parents, especially around disturbed offspring. 

- vaughen and leff looked at relapse rates of schizophrenics who retured to family home. higher relapse rates were found in homes with high expressed emotion (51%) than homes with lower expressed emotion(13%).

AO1: outline the cognitive approach to schizophrenia 

suggests that thought diusturbances are cause of SZ

Role of attention: frith's attention deficit theory says that most normal people are able to focus attention selectively and filter out irrelevant information, where as schizophrenics are unable to do this and therefore interpret irrelevant information as more significant and important than it actually is. 

Attentional bias: Bentall suggests that scizophrenics are biased towards paying attention to threatening and emotional stimuni 

AO2: evaluate the cognitive approach to schizophrenia 

harvey and keefe found that diminished cognitive ability is a core feature of SZ. severely impaired performance on cognitive tests ( two standard deviation below the mean of healthy controls) in several cognitive domains is strong evidence for the importance of cognitive impairment in the disorder.