Characteristics of Psychotic Disorders

I'm Dr

Cody Porter.

I'm a senior lecturer in psychology at U E Bristol,

and today's lecture is going to focus on characteristics of psychotic disorders.

Specifically, we're going to focus on schizophrenia.

So schizophrenia is a mental health disorder that's part of the

schizophrenia spectrum and other psychotic disorders in the DS m five.

So the DS M and the I CD 10 are used to diagnose patients.

Throughout the course of this lecture, we're going to focus on the DS M.

So schizophrenia spectrum and other psychotic disorders is

defined by abnormalities in one of the following

delusions. Hallucinations, disordered thinking,

grossly disorganised or abnormal motor behaviour

or negative symptoms.

Now delusions are fixed beliefs that are not amenable

to change in the light of con conflicting evidence.

So these are things that somebody believes

they don't change. No matter what you tell them. No matter what evidence you have,

they can begin suddenly or they can develop over the course of weeks or even months.

Hallucinations are usually auditory or visual,

and these are perceptions that aren't actually present in reality.

So this can include things like hearing voices.

It can include things like, um, watching a TV,

but thinking that actually the TV presenter is talking directly to you.

And disorder thinking is usually associated with, uh, speech symptoms,

so this can be things like having a word salad.

Now a word salad is when a person's trying to construct a sentence, but instead

they just come up with a lot of different words.

It's almost like the words just pour out of their mouth and don't make much sense.

Grossly disorganised or abnormal motor

behaviour can include things like catatonia

and negative symptoms are things like, uh, becoming withdrawn,

becoming less social and diminished emotional expression.

Now that's for schizophrenia spectrum and other psychotic disorders.

What we're now going to look at is we're now going to focus on schizophrenia.

So for schizophrenia, there must be two or more of the following,

and each must be pre present for a significant proportion of time,

so usually during the course of a one month period,

less so if this is being successfully treated.

OK, so at least one must be from the 1st, 2nd or third category.

So that is

just a recap. Delusions, hallucinations, disordered speech,

grossly disorganised or catatonic behaviour and negative symptoms.

OK, so that's P. That's schizophrenia. We're now going to talk about psychosis,

So psychosis is described as an episode

that involves a distortion or a break from reality. A

period of psychosis is usually referred to as a psychotic episode.

During a psychotic episode, a person has difficulty, uh,

determining what's real from what is imagined or

from what's part of their psychotic episode.

Now, psychosis doesn't have a specific cause,

but rather it's a symptom of several different conditions.

So this can be mental illness,

including psychotic disorders such as schizophrenia.

It can be in relation to mood disorders such as bipolar disorder.

Psychotic episodes can come as a result of sleep deprivation

are as a result of general medical conditions.

And certain prescription drugs can also cause this.

What you also find is a substance abuse,

including alcohol and drugs such as marijuana can also lead to psychotic episodes.

So it's important to note the difference between schizophrenia

and psychosis because they're not the same thing.

Psychosis is when people lose contact with reality.

Now this might involve seeing or hearing things that other people can't see or hear,

so those are hallucinations,

or it can involve belief in things that aren't actually true. So those delusions,

while sometimes these terms are erroneously used interchangeably,

they are not the same thing.

Schizophrenia is a mental disorder.

Psychosis refers to a loss of touch with reality.

Schizophrenia is a disorder characterised by a number of symptoms,

including psychotic symptoms or psychotic episodes.

So what this means is that people who have schizophrenia experience psychosis.

However,

people experiencing psychosis don't necessarily have to have schizophrenia.

So we're now going to think about the validity

of these diagnoses specifically in relation to schizophrenia.

So when we think about Roshan

and Roshan's

1973 research,

his famous experiment on pseudo patients let eight normal people being

kept in a hospital despite having no actual mental health disorder.

Now this suggests that actually,

doctors have no valid method for detecting schizophrenia.

They assumed that these

pseudo patients were actually schizophrenic despite no real evidence of this.

And in a follow up study,

they found that the hospital actually

rejected people who had genuine schizophrenic symptoms

because they assumed that there was more deception taking place.

So again,

this highlights difficulty with validity of diagnosis.

So neuropsychologist Michael Green suggests that actually neurocognitive

deficits in basic functioning such as memory problems,

attention central executive and problem solving skills are

actually what we label as being schizophrenic.

So he suggests an alternative explanation to this

and some of the risk factors that we should consider when we think

about schizophrenia and how we go about diagnosing this are things like genetics,

stress, substance misuse,

childhood trauma and social isolation.

Sullivan and colleagues in 2003 conducted a meta analysis of 12 twin studies,

and what they found was the heritability was actually found in 81% cases,

and actually environmental influence was only found 11% of the time.

Now this links in nicely with the biological causes.

Gosman in 1991 found that identical twins

have 48% risk of developing schizophrenia,

whereas non identical twins have a lower risk of just 17%.

So there is evidence that a higher degree of genetic relatives

can lead to a higher risk of developing schizophrenia,

and Ben

and colleagues in 2007 support this.

They suggest that there's that there's

actually three genes associated with schizophrenia,

and they've all been associated with access dopamine in specific D two receptors.

Now they suggest that this leads to acute episodes and positive symptoms,

which include delusions and hallucinations.

Another explanation is biochemical explanations.

So specifically the dopamine hypothesis.

And the dopamine is a neurotransmitter,

and it's one of the chemicals in the brain that cause the neurons to fire.

The original dopamine hypothesis stated that schizophrenia or people

with schizophrenia suffer from excessive amounts of dopamine,

and this causes neurons that use dopamine to fire. Too often

this means they transmit too many messages.

Now. Criticism of this is what comes first so that chicken and egg scenario

is it a case that too much dopamine is causing schizophrenia?

Or is it a case that the schizophrenia is causing too much dopamine?

So it is a difficult one to pin down,

especially when we think of those biochemical explanations.

And interestingly, Far

and colleagues in 1990 found no evidence between those who have schizophrenia's

level of dopamine compared with what they deemed as healthy individuals.

So people with a non schizophrenia diagnosis

also Noel in 2009,

argues that

one third of patients do not respond to drugs that block the dopamine receptor.

So actually there might be other neurotransmitters involved in schizophrenia.

It's not simply just a case of one thing,

so schizophrenia is quite a common mental disorder,

and it's one that's widely debated within the literature.

Lots of clinicians will argue that actually schizophrenia is too big

and it should be broken down into several smaller mental disorders.