Psychosis as a continuum Flashcards
What would be needed to say a disease was entirely dichotomous?
If the disease was caused by just one gene. 100% penetrant.
What was the first utterance of psychotic continuum?
Paul Meehl 1962:
SZ gene * - Schizotaxia to either:
*later proven to be polygenic
Schizotypy
or
Schizophrenia8
*Later several phenotypes of schizotaxia
Now schizotaxi may be back in vogue
What did van Os find in his studies of Psychosis?
That clinical populations had “a point on continua”
That non clinical populations showed symptoms.
Study in 2000
showed: 8.7% delusions and 3.3 % true
Showed 6.2% hallucinations and 1.7% true.
What did van Os find with regards to prevalence rates and time course?
5% median prevalence rates
3% median incidence rates
75-90% goes away
What are the rates of psyhcotic like symptoms, symptoms and full psychosis?
8%, 4% and 3%
Are PLE significant?
Yes, they carry a three fold increase in risk of psychosis.
What are the two main arguments for the theory of continuum?
That the general population exhibits symptoms.
Continua is easier to dissect and achieve progress.
What are the criticisms of the continuum theory?
Stephen Lawrie:
1: General population existence is not enough to say the symptoms are indistinct
2: The variety of individual symptoms makes progress harder and less reliable.
3: Continuous measures in medicine require single dimension reliable measures.
4: There is a need for dichotomy when detaining or medicating people.
What are the two ways to measure psychotic symptoms and if there a difference in results?
CAARMS and CAPE:
Yes: self reporting like in CAPE is a poor estimate of psychotic symptoms.
What are the main critiques of this continuum theory?
Lack of scientific evidence.
Questionable clinical utility
No clear advantage compared to categories
Based on a severe epistemological error.
