Schizophrenia
Diagnosis and Classification of Schizophrenia:
- Schizophrenia is a serious mental disorder. Diagnosis and classification of Schizophrenia
- There is no single defining characteristics of Issues in diagnosis and classification of schizophrenia
schizophrenia.
Biological explanations for schizophrenia
- DSM-5 – one positive symptom must be
present (delusions, hallucinations, or speech Psychological explanations for schizophrenia
disorganisation Drug therapy
- ICD-10 – two or more negative symptoms are
sufficient for diagnosis (avolition and speech Psychological therapies for schizophrenia
poverty). Management of Schizophrenia
Positive Symptoms:
- A positive symptom is an excess or distortion of The interactionist approach to schizophrenia
normal function. They are behaviours with a
loss of touch with reality.
- They occur in short episodes with normal periods in between and generally respond well to medication.
- Delusions
o Bizarre beliefs that seem real but are not
o Can be paranoid in nature, may also have an inflated belief about the person’s power and
importance.
o Delusions of reference is when events in the environment appear to be related to them.
- Hallucinations
o Bizarre perceptions of environment, usually auditory but can be visual, olfactory (smelling
things), tactile (bugs crawling under skin)
- Thought disorders (experiences of control)
o Thought and actions are perceived as under external control. May believe thoughts are being
inserted withdrawn or broadcasted to others.
o An indicator is divergent, incoherent, or loosely associated speech.
Negative Symptoms:
- A negative symptom is a reduction or loss of normal functions.
- They persist even in the absence of positive symptoms.
- Long lasting episodes, resistant to medication.
- Sufferers are not able to function effectively in society.
- Speech poverty (Alogia)
o Lessening of speech fluency and productivity.
o Reflects slowing or blocked thoughts
o Delay in verbal responses or give brief replies.
- Avolition
o Inability to initiate goal-directed behaviour – often mistaken for disinterest
o E.g., poor hygiene and grooming, lack of persistence in work or education, lack of energy
- Psychomotor disturbances
o Reduction in range or intensity of emotional expression including facial expression, voice tone,
eye contact and body language
o Sufferers can adopt frozen statue like poses.
Issues in Diagnosis and Classification of Schizophrenia:
Reliability:
- Reliability is a measure of consistency of symptom measurement.
- There is inter-rater reliability is when different clinicians reach the same diagnosis.
- Test-retest reliability is when the same clinician reaches the same diagnosis on two different occasions.
, - Cheniaux et al (2009) had two psychiatrists diagnose patients using both DSM and ICD criteria. They
found poor inter-rater reliability. The first psychologist diagnosed 26 with schizophrenia using the DSM
and 44 using the ICD. The second diagnoses 13 with the DSM and 24 using the ICD. This inconsistency
between mental health professionals and the different classification systems is a limitation of the
diagnosis.
- However, there may be issues with this research. A diagnosis cannot be made until a patient is
clinically interviewed. Psychiatrists are relying on retrospective data, and the patient’s ability to recall
relevant information accurately. Some patients may be exaggerating the truth or lying. The interview
with the two psychologists may not be consistent.
+ Osorio et al (2019) suggest that the reliability in diagnosis for schizophrenia has improved. They studied
180 individuals using the DSM-5 and found +0.97 inter-rater reliability in pair of interviewers and a
test-retest reliability of +0.92.
Validity:
- Validity is whether or not we are assessing what we are trying to assess.
- Predictive validity is if diagnosis leads to successful treatment, then the diagnosis is seen as valid.
- Descriptive validity is that to be valid, patients with schizophrenia should differ in symptoms from
patients with other disorders.
- Aetiological validity is that to be valid, all schizophrenics should have the same cause for the disorder.
- Criterion validity is whether different assessment systems arrive at the same diagnosis.
- Cheniaux et al (2009) had two psychiatrists diagnose patients using both DSM and ICD criteria. The
first psychologist diagnosed 26 with schizophrenia using the DSM and 44 using the ICD. The second
diagnoses 13 with the DSM and 24 using the ICD. This suggests that one of the diagnosis systems must
over or underdiagnose patients. This suggests that the criterion validity is low.
Co-morbidity:
- Co-morbidity is where one or more disorders occur simultaneously with schizophrenia.
- This can cause problems with the reliability of the diagnosis as there may be confusion over which
disorder is being diagnosed.
- This may mean that clinicians administer incorrect or ineffective treatments.
- Also, if two conditions often occur together, we may question whether they are actually a single
condition.
- Buckley et al (2009) found that 50% of patients with schizophrenia also have a diagnosis of
depression. 47% of patients with schizophrenia also have substance abuse. Very severe depression can
look like schizophrenia and vice versa, therefore they may just be one condition. This is also a limitation
because it could mean that clinicians may administer incorrect or ineffective treatments.
Gender Bias:
- There are suggestions that the majority of clinicians are men, and they misapply diagnostic criteria to
women.
- Males tend to suffer more negative symptoms than women
- Males tend to have higher rates of substance abuse
- Females have better recovery rates and lower relapse rates.
- There are also different predisposing factors which give men and women different vulnerability at
different points in life.
- Males first onset is typically between 18 and 25. They have 2 peaks at 21 and 39.
- Females first onset is generally between 25 and 35. They have 3 peaks at 22, 37 and 62.
- Longenecker et al (2010) found that since the 1980s men have been diagnosed more often than
women.
- Cotton et al (2009) found that female patients typically function better than men. This may be
why the diagnosis rates are lower in women as their better interpersonal functioning may bias
practitioner to under-diagnose schizophrenia. This is an issue as men and women suffering the same
Diagnosis and Classification of Schizophrenia:
- Schizophrenia is a serious mental disorder. Diagnosis and classification of Schizophrenia
- There is no single defining characteristics of Issues in diagnosis and classification of schizophrenia
schizophrenia.
Biological explanations for schizophrenia
- DSM-5 – one positive symptom must be
present (delusions, hallucinations, or speech Psychological explanations for schizophrenia
disorganisation Drug therapy
- ICD-10 – two or more negative symptoms are
sufficient for diagnosis (avolition and speech Psychological therapies for schizophrenia
poverty). Management of Schizophrenia
Positive Symptoms:
- A positive symptom is an excess or distortion of The interactionist approach to schizophrenia
normal function. They are behaviours with a
loss of touch with reality.
- They occur in short episodes with normal periods in between and generally respond well to medication.
- Delusions
o Bizarre beliefs that seem real but are not
o Can be paranoid in nature, may also have an inflated belief about the person’s power and
importance.
o Delusions of reference is when events in the environment appear to be related to them.
- Hallucinations
o Bizarre perceptions of environment, usually auditory but can be visual, olfactory (smelling
things), tactile (bugs crawling under skin)
- Thought disorders (experiences of control)
o Thought and actions are perceived as under external control. May believe thoughts are being
inserted withdrawn or broadcasted to others.
o An indicator is divergent, incoherent, or loosely associated speech.
Negative Symptoms:
- A negative symptom is a reduction or loss of normal functions.
- They persist even in the absence of positive symptoms.
- Long lasting episodes, resistant to medication.
- Sufferers are not able to function effectively in society.
- Speech poverty (Alogia)
o Lessening of speech fluency and productivity.
o Reflects slowing or blocked thoughts
o Delay in verbal responses or give brief replies.
- Avolition
o Inability to initiate goal-directed behaviour – often mistaken for disinterest
o E.g., poor hygiene and grooming, lack of persistence in work or education, lack of energy
- Psychomotor disturbances
o Reduction in range or intensity of emotional expression including facial expression, voice tone,
eye contact and body language
o Sufferers can adopt frozen statue like poses.
Issues in Diagnosis and Classification of Schizophrenia:
Reliability:
- Reliability is a measure of consistency of symptom measurement.
- There is inter-rater reliability is when different clinicians reach the same diagnosis.
- Test-retest reliability is when the same clinician reaches the same diagnosis on two different occasions.
, - Cheniaux et al (2009) had two psychiatrists diagnose patients using both DSM and ICD criteria. They
found poor inter-rater reliability. The first psychologist diagnosed 26 with schizophrenia using the DSM
and 44 using the ICD. The second diagnoses 13 with the DSM and 24 using the ICD. This inconsistency
between mental health professionals and the different classification systems is a limitation of the
diagnosis.
- However, there may be issues with this research. A diagnosis cannot be made until a patient is
clinically interviewed. Psychiatrists are relying on retrospective data, and the patient’s ability to recall
relevant information accurately. Some patients may be exaggerating the truth or lying. The interview
with the two psychologists may not be consistent.
+ Osorio et al (2019) suggest that the reliability in diagnosis for schizophrenia has improved. They studied
180 individuals using the DSM-5 and found +0.97 inter-rater reliability in pair of interviewers and a
test-retest reliability of +0.92.
Validity:
- Validity is whether or not we are assessing what we are trying to assess.
- Predictive validity is if diagnosis leads to successful treatment, then the diagnosis is seen as valid.
- Descriptive validity is that to be valid, patients with schizophrenia should differ in symptoms from
patients with other disorders.
- Aetiological validity is that to be valid, all schizophrenics should have the same cause for the disorder.
- Criterion validity is whether different assessment systems arrive at the same diagnosis.
- Cheniaux et al (2009) had two psychiatrists diagnose patients using both DSM and ICD criteria. The
first psychologist diagnosed 26 with schizophrenia using the DSM and 44 using the ICD. The second
diagnoses 13 with the DSM and 24 using the ICD. This suggests that one of the diagnosis systems must
over or underdiagnose patients. This suggests that the criterion validity is low.
Co-morbidity:
- Co-morbidity is where one or more disorders occur simultaneously with schizophrenia.
- This can cause problems with the reliability of the diagnosis as there may be confusion over which
disorder is being diagnosed.
- This may mean that clinicians administer incorrect or ineffective treatments.
- Also, if two conditions often occur together, we may question whether they are actually a single
condition.
- Buckley et al (2009) found that 50% of patients with schizophrenia also have a diagnosis of
depression. 47% of patients with schizophrenia also have substance abuse. Very severe depression can
look like schizophrenia and vice versa, therefore they may just be one condition. This is also a limitation
because it could mean that clinicians may administer incorrect or ineffective treatments.
Gender Bias:
- There are suggestions that the majority of clinicians are men, and they misapply diagnostic criteria to
women.
- Males tend to suffer more negative symptoms than women
- Males tend to have higher rates of substance abuse
- Females have better recovery rates and lower relapse rates.
- There are also different predisposing factors which give men and women different vulnerability at
different points in life.
- Males first onset is typically between 18 and 25. They have 2 peaks at 21 and 39.
- Females first onset is generally between 25 and 35. They have 3 peaks at 22, 37 and 62.
- Longenecker et al (2010) found that since the 1980s men have been diagnosed more often than
women.
- Cotton et al (2009) found that female patients typically function better than men. This may be
why the diagnosis rates are lower in women as their better interpersonal functioning may bias
practitioner to under-diagnose schizophrenia. This is an issue as men and women suffering the same
