hello and welcome to class one of schizophrenia This video will cover the classification of
schizophrenia. We will talk about the symptoms you need to have to
actually be diagnosed with schizophrenia, known as positive and negative symptoms.
But diagnosing schizophrenia is not fool proof, we are also going
to discuss a number issues with diagnosis concerning both validity and reliability.
Schizophrenia is a mental health disorder that affects around 1 percent of
the British population, the first symptoms usually appear between 15 and 45, and men are much more
likely to develop schizophrenia than women. A common misconception is schizophrenia is
about having multiple personalities, but that is a disorder termed dissociative personality disorder.
A good definition for schizophrenia would describe it as a break from reality. That
describes well it's two positive symptoms. Which are hallucinations and delusions.
When I describe the symptoms for schizophrenia I will say they are either positive or negative.
It's important not to be confused by these terms, positive means experiences that are in
addition to normal experience, so what people with schizophrenia experience that
non sufferers don't. Negative symptoms are a lack of normal experiences or abilities,
so what people with schizophrenia don't experience that non sufferers do.
So let's go describe some examples of the symptoms. Identification of these symptoms
is the job of a clinician and they will be using a guide. Either the diagnostic
statistical manual known as the DSM-5, or the ICD, the international classification of disease.
To be diagnosed with schizophrenia two of the following symptoms need to be present
for at least a month, and one of the symptoms has to be a positive symptom.
Hallucinations are a positive symptom. They are additional sensory experiences,
someone with could experience visual hallucinations, seeing objects that are distorted,
or even things that are not there at all. Auditory hallucinations could be sounds,
but a common auditory hallucination is hearing voices that are often critical and abusive.
A separate positive symptom is delusions. These are irrational beliefs about themselves,
the people around them or the world. Example delusions are persecution,
feeling people are out to get them. Or delusions of grandeur, like thinking they are royalty.
So those are the positive symptoms, There are a range of negative symptoms,
but the ones I will focus on are avolition and speech poverty.
Avolition is a loss of normal motivation and energy, people with avolition are
less sociable and are less likely to look after their personal hygiene.
Speech poverty is a loss of depth in the sufferers communication. So speech can be brief,
and when they do talk it is disorganized and there may be missing words. Speech however can become
so disorganized that random words are added and the speaker wanders off the point jumping from
topic to topic, if speech is this disorganised we would then classify this as a positive symptom.
so we've talked about classification systems and some of the key symptoms of schizophrenia.
But correctly diagnosing a case of schizophrenia isn't necessarily as
simple as checking the symptoms in the DSM. In the rest of this need to consider both
the reliability and validity of schizophrenia. A quick reminder, reliability is the if results we
gain from our measuring tool are consistent, so if someone is assessed multiple times
they get the same diagnosis. And validity is about truth so is it true that an individual
has schizophrenia or that schizophrenia exists as a distinct and clearly definable mental illness?
When considering reliability there is inter-rater reliability,
do two medical professionals reach the same diagnosis when assessing the same patient?
If one doctor gives a diagnosis of schizophrenia but the other gives a diagnosis of depression
then we don't have inter-rater reliability. There is also test retest reliability,
this is if the same doctor gives the same diagnosis over time.
So if she assesses someone with having schizophrenia in March
if she changes the diagnosis to OCD in May there is a lack of test retest reliability.
Evaluating the reliability of schizophrenia diagnosis Beck in 1963 reviewed the diagnosis
of 153 patients who had been diagnosed by multiple doctors. The results showed only a 54% concordance
rate between the doctors diagnosis. This means that Inter-rater reliability of schizophrenia
diagnosis is low and suggests that many people may be being miss diagnosed and potentially receiving
inappropriate treatment or not diagnosed and missing out on treatment they need.
When considering validity we have a few ideas to discuss, firstly is a concept called co-morbidity.
This simply means that schizophrenia is often diagnosed alongside other mental
health conditions. We see evidence for this in research by Buckley 2009 showing schizophrenia
assessed alongside depression 50% of the time and drug abuse 47%, PTSD 29%, OCD 23%.
This suggests the treatment of schizophrenia is complecated and there may not be a clear
distinction between schizophrenia and other conditions such as depression.
Similar to that point we have the issue of symptom overlap. A number of mental
health conditions share the same symptoms as schizophrenia, people with the diagnosis
of bio-polar for example can have both of the positive symptoms of hallucinations and delusions.
The fact there is such significant symptom overlap leads us to question if bio-polar and
schizophrenia are actually two separate and distinct mental health conditions.
Perhaps we need to rethink completely the definitions we use for schizophrenia,
undermining it's validity as a diagnosis. Another consideration is the potential for
gender bias in the diagnosis of schizophrenia. Men and women are equally likely to develop
schizophrenia over the course of their lifetimes, but we do see gender differences
Men tend develop symptoms earlier, peaking at around 25 women are diagnosed on average
5 years later. Men have worse social functioning and are more likely to abuse alcohol and drugs as
a co-morbidity. Men are more likely to develop negative symptoms, and women positive symptoms.
Some psychologists argue that womens experience of schizophrenia is taken less seriously and
more likely to be underdiagnosed. Cotton suggests this is because women's issues
are not taken as seriously because of women's better social ability and coping strategies,
also because of this ability to cope, they are less likely to access treatment.
As well as gender bias there is evidence for culture bias,
in particular in the UK with people who have an afro-carribian heritage
being nine times more likely to be diagnosed with schizophrenia over the course of their lifetimes
than the general population. (2005: Fearon) if a genetic vulnerability was the explanation for
the increased risk of diagnosis we would expect to see high levels of schizophrenia in the Caribbean.
However a range of studies in the 1990's conducted in Jamaica, Trinidad, and Barbados
showed the same 1% likelihood as the UK. Its suggested that the explanation is
misdiagnosis, that due to cultural differences afro-carribians are being over diagnosed.
Fernando suggests this is due to what he calls a category failure.
Where western definitions of mental illness are applied to people from non western cultures.
One particular aspect of Afro-carribian culture that may be being misinterpreted
is the religious experience of hearing the voices of angels. This is more common and acceptable in
Afro-carribian society than western culture. While a western doctor may see this as a hallucination,
a Afro-carribian doctor may interpret this a religious experience.
Loring and Powell provide research evidence for diagnostic bias in both gender and race.
They sent the same two case studies to 290 psychiatrists. But they said the case studies
were either from a white male, a black male, white female or black female or no details on gender or
race. It was found that the sex race of both the client and psychiatrist influenced the diagnosis.
Women were less likely to be given a diagnosis of schizophrenia, and black clients more likely. The
most accurate diagnosis was when the clients race and sex was the same as the psychiatrist.