Clinical Characteristics of Schizophrenia including reliability and
validity.
AO1
Brief facts and figures
50 times higher risk of attempting suicide
Suicide is number one cause of
premature deaths among people with
schizophrenia
Over a lifetime, about 1% of the
population will develop schizophrenia
DSM-V
Diagnostic and statistical
manual of mental disorders 5th
edition
Certain groups of
symptoms can be classed
together as a syndrome
Allows mental disorders to
be diagnosed and treated
Selective criteria from DSM-V
Must have two or more
characteristic symptoms present
for a significant portion of time
e.g. delusions,
hallucinations, disorganised
speech
Social/occupational
dysfunction for a significant
portion of time
Duration: continuos signs
of disturbance for at least
6 months
Positive and negative symptoms
Positive Symptoms are
those that appear to reflect
an excess or distortion of
normal functions
e.g. delusions,
hallucinations, disrorganied
speech
Negative Symptoms are those
that appear to reflect a loss of
normal functions
e.g. effective flattening, alogia, avolition
AO2
DSM-V
Advantage of the DSM-V is that
therapies are usually specific to
certain disorders so a reliable
diagnosis can point to a particular
type of therapy
Disadvantage of the
DSM-V is misdiagnosis as
if this occurs, it could lead
to inappropriate treatment
and sometimes, wrongful
institutionalisation
Reliability
Refers to the consistency of a
measuring instrument to asses
and diagnosis schizophrenia
Inter-rater reliability refers to
whether two independent
assessors give similar diagnoses
Challenges- WHALEY (2001)- found inter-rater
reliability correlations in the diagnosis of
Schizophrenia as low as +0.11
Supports- Jakobsen et al. (2005)
took a random sample of 100
danish patients with a history of
psychosis and found high
sensitivity of inter rater reliability of
93%
AO3- Cultural Bias
Test-retest reliability refers to
whether tests used to deliver
these diagnoses are
consistent over time
Supports- PRESCOTT et al. (1986) analysed the test retest reliability of
several measure of attention and information processing in 14 chronic
schizophrenics and found performances on these measures were
stable over 6 months
AO3- Longitudinal
Validity
Refers to the extent that a diagnosis represents
something that is real and distinct from other
disorders and that the extent the DSM-V measures
what it claims to measure
Comorbidity refers to the extent that two or more conditions
co-occur. Psychiatric comorbidities are common in
schizophrenics including substance abuse, anxiety and
symptoms of depression
Support- BUCKLEY et al. (2009) estimate that comorbid
depression occurs in 50% of patients and 47% of patients
also have a lifetime diagnosis of comorbid substance abuse.
This creates difficulties in the diagnosis of the disorder as
well as treatment.