Okay. So when we think about the diagnosis of schizophrenia,
as I said before,
it can be diagnosed according to one of two different systems.
It can be diagnosed according to
the International Classification of Disease system which is developed by
the World Health Organization or can be diagnosed according to
the DSM-5 which is sort of the American handbook or bible of psychiatric disorders.
For the purposes of this course,
I'll be defining in terms of the ICD,
the International Classification of Disease Version 10.
But again, I want to emphasize that it's highly overlapping with the DSM-5 diagnosis.
The ICD-10 diagnosis for schizophrenia consists of nine major classes of symptoms.
The first class of symptoms is thought echo,
thought insertion or withdrawal, or thought broadcasting.
We've already talked about several of these symptoms.
Thought broadcasting we didn't talk about that,
actually involves the idea that when one is thinking,
one's thoughts can be heard outside one's own sort of personal experience.
So for example, I've worked with
folks who might believe that they might be in a cafe with other people
and they have this experience of thought broadcasting where they feel like what they're
thinking is being heard by everyone
in the coffee shop as they walk into the coffee shops.
That's example of thought broadcasting.
So again, the first class of symptoms thought echo,
thought insertion, withdrawal and thought broadcasting.
Second class of symptoms includes delusions of control which we've already talked about.
This is where you believe that your behaviors or thoughts
are being controlled by an entity outside yourself.
A third category of symptoms according to the ICD-10 are
hallucinatory voices giving a running commentary on your behavior.
And we talked about this as well.
The idea of voices giving you a command,
telling you to do something,
pick up a glass, put a glass down, etc.
Those are the hallucinatory voices,
that's class C. The third class.
The fourth class are
persistent delusions of other kinds that are culturally inappropriate.
This might include what we described as grandiose delusions,
delusions that you are perhaps God or the Son of God.
The idea that you can change the weather,
that you're communicating with aliens in another universe.
These types of unusual ideas that usually involve some sense of having
large amounts of power are examples of the persistent delusions in Class D,
the fourth class in the ICD-10.
Class E are persistent hallucinations in any modality.
So these are persistent hallucinations in auditory processing,
or factory processing, or smell, any modality.
The next classification, classification F are breaks in
the train of thought resulting in incoherence or irrelevant speech.
And this would relate to the disorganization we talked about earlier in this lecture.
Catatonic behavior is Class G and catatonic behavior are things such as posturing,
unusual movements, being immobile for long periods of time,
having what's called waxy inflexibility where you might be frozen in one position.
Someone might move you to another position,
and then you just stay absolutely immobile in that new position that's
known as waxy flexibility or just a general stupor.
The next category category H of
the ICD-10 classification of symptoms are
negative symptoms which we've already talked about apathy,
avolition, alogia, we've already defined those terms.
Social withdrawal of course is very important.
And lastly, the last category is,
in this category I is
a significant and consistent change in
the overall quality of some aspects of personal behavior.
Manifest as a loss of interest, aimlessness,
idleness, or self-absorbed attitude.
Given these nine categories of symptoms,
in order to merit a diagnosis,
you have to have either one of these symptoms or
several of these symptoms for at least a period of a month.
If the symptoms are less than a month,
you would have a different diagnosis.
You might suspect the emergence of
schizophrenia but you wouldn't meet full criteria for it.
The ICD-10 criteria are somewhat different from the DSM-5.
And then, in the DSM-5,
one needs a six-month period of suffering from symptoms to merit a diagnosis.
In addition to these general groups of symptoms that are used to diagnose the disorder,
there are also what are called subtypes of the disorder that
the ICD-10 uses and refers to.
And the types of symptoms,
the types of subtypes that they might refer to one as subtype would be paranoid subtype.
And this is a subtype where people or
the clinical picture is largely dominated by paranoid delusions.
The idea that the CIA might be following you,
the idea that perhaps your phone is tapped,
your computer is being watched by someone else.
So those types of paranoid delusions that's the paranoid subtype.
There's also a disorganized or hebephrenic subtype.
The disorganized or hebephrenic subtype involves profound disorganization.
This is the word salad,
might include the word salad that we talked about before.
Sort of a disruption in the logical processes of thought.
A third subtype might be a subtype that's
primarily demonstrated through negative symptoms.
And this is a subtype where people show a lot of avolition, social withdrawal.
This is sort of a negative subtype of the disorder.
There's also been referred to as simple schizophrenia.
What simple schizophrenia is,
it's a form of schizophrenia which there really never florid psychotic symptoms.
You don't have symptoms such as delusions and hallucinations,
the sort of very striking powerful symptoms that are very noticeable to clinicians.
But instead, one might suffer from sort of
a gradual decrease in one's social interaction.
Over time a person might become more and more socially withdrawn.
Over time they may be less likely to interact with others,
may become more and more mute over time.
It tends to have an insidious onset of
gradual onset and progresses over many, many years.
And at no time again, do you have those florid symptoms and that's
known as simple schizophrenia.
There is also a mixed subtype and this is often, in some studies,
this has been indicated to be the most commonly diagnosed subtype.
And in the mix subtype, you have elements
of the different subtypes that we've talked about.
You might have paranoid symptoms,
you might have disorganized symptoms,
you might have negative symptoms.
So it's a mix of these different subtypes.
So another feature of
schizophrenia that is not involved in the diagnosis of the disorder,
but over the last 20 years has really come to be recognized as
a key element of the disorder, are cognitive deficits.
Evidence suggest that cognitive difficulties which represent
difficulties in attention, in memory,
in problem solving, lead to
more difficulties in everyday life for people with schizophrenia,
than positive symptoms which is most often used to diagnose the disorder.
People with these deficits in
cognition may have trouble understanding or remembering what people say,
finishing a job or chore,
or remembering to do things.
People with schizophrenia, many people with schizophrenia,
have these difficulties in cognition and current estimates suggest that if you
take into account sort of baseline cognitive functioning.
So the idea that you're taking in
what people sort of intellectual capacity is if you account for that,
just about everyone with schizophrenia has some detriment in their cognitive skills.
So if we take a look at
this diagram of people with schizophrenia and if you look on the X or bottom axis,
those are areas of cognition.
They include obstruction, attention, verbal memory,
spatial memory, language, spatial ability,
sensory ability and motor ability.
You can see that people with schizophrenia have
deficits across all those areas of cognition.
So all those different cognitive skills,
people with schizophrenia on a mean basis in groups,
show deficits on these tests relative to healthy controls.
So this does in fact suggest that cognitive deficits are very common in the disorder
and they affect a wide range of different cognitive functions.
The other thing that's important to see from this diagram is,
if you look at the dotted line,
the dotted line in fact looks at people with schizophrenia,
the same people with schizophrenia assessed about a year and a half later.
These folks have been diagnosed with schizophrenia,
they've been treated with oral anti-psychotic medication and yet as you can see
the cognitive deficits are almost identical to what you see at initial assessment.
Suggesting not only that there are
these fairly profound cognitive deficits across a wide array of areas, but in addition,
treatment of the symptoms of schizophrenia with
contemporary psycho-pharmacologic interventions don't
seem to have an impact on the nature of
the cognitive difficulties even a year and a half later.
So the cognitive difficulties seem to be relatively
resistant to the effects of anti-psychotic medication.
So these cognitive difficulties have really in many ways been a new line of treatment in
our understanding of the disorder and are important new target for novel treatments.