7 detailed essay plans based on the Illuminate publishing textbook, answering the 16 markers provided at the end of each topic and covers all AO1 and AO3 points. Each plan can be translated easily into a top-band essay.
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SCHIZOPHRENIA:
Discuss reliability and validity in relation to the diagnosis and/or classification of
schizophrenia [16 marks]
AO1:
- Schizophrenia is a serious mental disorder experienced by about 1% of the
world’s population. It is more commonly diagnosed in men, city-dwellers, and
lower-socioeconomic groups.
- There are two major systems for the classification of mental disorder, the
World Health Organisations International Classification of Disease (ICD-10,
now 11) and the American Psychiatric Associations Diagnostic and Statistical
Manual Edition 5 (DSM-5)
- After classification, diagnosis is possible by identifying symptoms and
deciding what disorder a person has.
- In the case of schizophrenia, there are 2 types of symptoms: positive and
negative.
- Positive symptoms include hallucinations and delusions. Hallucinations are
unusual sensory experiences and can occur in relation to any sense, for
example: seeing distorted facial expressions or occasionally people or
animals that are not there.
- Delusions, also known as paranoia, are irrational beliefs. These can take a
range of forms with common delusions involving being an important historical,
political, or religious figure. They may also commonly involve being
persecuted, perhaps by government or aliens.
- Negative symptoms involve the loss of usual abilities and mainly include
avolition and speech poverty.
- Speech poverty is a reduction in the amount and quality of speech. This is
sometimes accompanied by a delay in the persons verbal responses during
conversation. However, more recently there is emphasis on speech
disorganisation in which speech becomes incoherent or the speaker changes
topic mid-sentence.
- Avolition is described as finding it difficult to begin or keep up with goal-
directed activity, i.e., actions performed in order to achieve a result. People
with schizophrenia often have sharply reduced motivation to carry out a range
of activities.
- The DSM-5 diagnoses schizophrenia as having one or more of the positive
symptoms whereas two or more negative symptoms are sufficient under ICD.
AO3:
- One strength of the diagnosis of schizophrenia is its reliability. Reliability
means consistency and a psychiatric diagnosis is said to be reliable when
different diagnosing clinicians reach the same diagnosis for the same
individual and when the same clinician reaches the same diagnosis for the
same individual on two occasions. Prior to DSM-5, reliability for schizophrenia
diagnosis was low but this has now improved using the DSM-5. Osorio found
that pairs of interviewers diagnosing schizophrenia had an inter-rater reliability
of +.97 and test-retest reliability of +.92
- One limitation of the diagnosis of schizophrenia is its validity. In general,
validity concerns whether we assess what we are trying to assess. One way
, to assess validity of a psychiatric diagnosis is criterion validity. Cheniaux et al
had two psychiatrists independently assess the same 100 patients using ICD-
10 and DSM-5 criteria and found that 68 were diagnosed with schizophrenia
under ICD system and 39 under DSM. This suggests that schizophrenia is
either over or underdiagnosed according to the diagnostic system.
- Another limitation of schizophrenia diagnosis is its co-morbidity with other
conditions. If conditions occur together a lot of the time, then this calls into
question the validity of their diagnosis and classification because they might
actually be a single condition. Schizophrenia is commonly diagnosed with
other conditions, for example, one review found that about half of those
diagnosed with schizophrenia also had a diagnosis of depression or
substance abuse. This is a problem for classification because it means
schizophrenia may not exist as a distinct condition and is a problem for
diagnosis as at least some people diagnosed with schizophrenia may have
unusual cases of conditions like depression.
Describe and evaluate biological explanations for schizophrenia [16 marks]
AO1:
- One biological explanation for schizophrenia is genetic basis.
- Family studies have confirmed that risk of schizophrenia increases in line with
genetic similarity to a relative with the disorder. For example, someone with
an aunt with schizophrenia has a 2% chance of developing it, increasing to
9% if the individual is a sibling and 48% if they are an identical twin. Of
course, family members tend to share aspects of their environment as well as
many of their genes so the corelation represents both.
- The genetic basis also refers to candidate genes. Early research in this area
looked for a single genetic variation in the belief that one faulty gene could
explain schizophrenia. However, it appears that a number of different genes
are involved, i.e., schizophrenia is polygenic. The most likely genes would be
those coding for neurotransmitters including dopamine. Ripke et al combined
all previous data from genome-wide studies of schizophrenia and found 108
separate genetic variations were associated with slightly increased risk of
schizophrenia.
- Schizophrenia can also have a genetic origin in the absence of a family
history of the disorder. One explanation for this is mutation in parental DNA
which can be caused by radiation, poison, or viral infection. Evidence for
mutation comes from positive corelations between paternal age and risk of
schizophrenia, increasing from around 0.7% with fathers under 25 to over 2%
in fathers over 50.
- Another biological explanation of schizophrenia is the neural correlates
explanation. This is the idea that patterns of structure or activity in the brain
that occur in conjunction with an experience and may be implicated in the
origins of that experience. The best-known neural correlate of schizophrenia
is the neurotransmitter dopamine.
- The original dopamine hypothesis was based on the discovery that drugs
used to treat people with schizophrenia caused symptoms similar to those in
people with Parkinson’s disease, a condition associated with low dopamine.
Therefore, schizophrenia might be the result of high levels of dopamine in
subcortical areas of the brain. For example, an excess of dopamine receptors
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