Diagnosis of schitzophrenia

what is the prevelance of schizophernia ?

affects 1% of the population

what is classification ?

the process of grouping things on their similarities

what is diagnosis ?

identification of a disease / disorder

what are the two main classification systems ?

DSM-5 and ICD-10

what are positive symptioms?

additional experiences beyond those of ordinary existence.

what are the main positive symptoms of schizophrenia ?

hallucinations + delusions

What are hallucinations?

false sensory experiences, such as seeing something in the absence of an external visual stimulus

What are delusions ?

false beliefs

What are the different types of delusions ?

Persecutory delusions (an individual is going to be harmed)

Referential delusions (certain gestures, comments to an individual)

Grandiose delusion (individual beliefs that they have exceptional abilities)

Erotomaniac delusions (individual beliefs falsely that another person is in love with them)

Nihilistic delusions (a catastrophe will occur)

Somatic delusions (health and organ functions)

What are negative symptoms ?

loss of usual abilities and experiences

What are the negative symptoms of schizophrenia?

speech poverty and avolition

What is speech poverty ?

Reduction in the amount and quality of speech --> DSM empasises speech disorganisation and incoherence as a positive symptom

What is avolition ?

severe loss of motivation to carry out everyday tasks

What are the two types of schizophrenia ?

Type 1 - acute

Type 2 - chronic

What has to be valid in the diagnosis of schizophrenic ? (tree types of validity involved)

1) predictive validity

2) descriptive validity (DSM has higher than ICD)

3) Aetilogical validity (means same causes for all suffers)

Strength of diagnosis is good reliability / improving :

consistent results between inter-rate and test - retest results

Beck 54% in (1963)

Soderberg 81% (2003)

Limitation of diagnosis is low validity :

Criterion validity = evaluates how accurately a test measures the outcome it was designed to measure.

what is cheniaux et al study for validity + reliability ?

had two psychiatrists independently assess the same 100 clients.

68 diagnosed with schizophrenia with ICD and 39 with DSM

Psychists 2 made half the diagnosis of psychist 1.

limitaiton for diagnosis is co-morbidity with other conditions (often diagnosed with other conditions)

Buckley concluded that schizophrenia is co-morbid with depression (50% of cases) + substance abuse (47%)

-> suggests may not exist as a distinct condition

Limitaion for diagnosis is gender bias

men are diagmosed more than women

ration of 1.4: 1

-> could be because men are more genetically vunerable / women are better at masking symptoms

research for diagnosis gender bias :

Lewin : when clearer diagnosis criteria were given diagnosis of females drops

limitation in culture bias

symptoms such as hearing voices

-> Afro-Carribean societies hear voices from ancestors

(Cochrain research)

-> afro carribeans x7 more likely to be diagnosed

British men may overinterpret symptoms by UK psychiatrist

limitation is symptom overlap

overlap between the symptoms of schizophrenia and other conditions

-> bipolar disporder shapre many of the same symptoms

makes it hard to diagnose

Limitation of schizophrenogenic diagnosis (overlap with other disorders) Hewitt et al reserach :

Hewitt compared 14 schitzophrenic patients + 14 autistic patients

-> 7 of the autistic patients had symptoms of schitzophrenia

-> this could lead to individuals being misdiagnosed