Schizophrenia is a psychotic disorder which affects 1% of the population.


§  Positive symptoms – symptoms to do with presence

Hallucinations, delusions, thought and speech disturbances

§  Negative symptoms – symptoms to do with absence

Avolition, absence of emotion and absence of social functions


§  Criteria of DSM (Diagnostic and statistical manual of mental disorders)

A psychologist would diagnose an individual using this criteria, in which certain symptoms must be present for atleast 1 month (positive symptoms) while other symptoms have to be present for atleast 6 months (negative symptoms).


§  Subtypes of schizophrenia

-          Paranoid schizophrenia - hallucinations and delusions but normal cognitive functioning

-          Disorganized schizophrenia - disruption of thought processes and disorganised speech

-          Catatonic schizophrenia - disturbance in movement; sufferer may stop moving (catatonic stupor) or experience radically increased movement (catatonic excitement) aswell as imitation of another person’s movement (echopraxia)

-          Undifferentiated schizophrenia - symptoms are present but don’t fit the criteria for the other kinds of schizophrenia

-          Residual schizophrenia – symptoms stop or symptoms are not as severe


§  Problems with diagnosis

Reliability – A psychiatrists diagnoses may be different to other psychiatrists. Cooper et al watched videos of people getting diagnosed and found that psychiatrist’s in New York were more likely to diagnose schizophrenia than psychiatrists in London, who were more likely to diagnose manic depression.

Labelling – Diagnosis may lead to self-fulfilling prophecy, in which patients may play up to the role of having schizophrenia because they feel it is expected of them.

Misdiagnosis - Symptoms develop over time so when a patient is being diagnosed only a few symptoms may be present so they could be diagnosed with a mild form of schizophrenia when it’s much worse. Aswell as this, there are many cross-over symptoms which makes misdiagnoses common.

Implications for treatment – Drugs are used as a treatment for schizophrenia and with this many nasty side-effects can occur.



Biological explanations of schizophrenia


The genetic explanation

This suggests that there is a physical cause for schizophrenia, in which the disorder is

inherited through genes.


Gottesman et al carried out a correlation study and found that the lifetime risk of developing the disorder for monozygotic twins is 48% and for dizygotic twins it’s 17%. With 46% when both parents have the disorder compared to 13% when just one parent has it.

Evaluation This study shows that the development for schizophrenia does have a genetic basis. However as concordance between monozygotic genes wasn’t 100% some other factor must be involved to count for the other 52%. Aswell as this, the sample sizes are small so it could be argued that the study does not account for the entire population and therefore cannot be generalised.


The neurochemical explanation

Dopamine is a neurotransmitter that increases the firing of neurons at the synapse. With this, it has been found that people with schizophrenia have high


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