WEEK 3 Flashcards
(21 cards)
Meehl’s quasi-dimensional model of psychosis
- used the term schizotaxia to describe genetic predisposition to psychotic disorder. individuals with schizotaxia would then develop schizotypy or schizophrenia based on environmental factors.
- the limitation here is that his model favored the single major gene theory of schizophrenia (one schizo-gene).
- Meehl viewed schizotypy as the only clinical outcome of schizotaxia
advantages of the fully dimensional model of psychosis
1) provides a framework of description of the inter-individual heterogeneity and variation of phenotypic expression
2) integrates most of the elements of the quasi-dimensional model
3) includes transitory anomalous experiences in the general non-clinical population
Stephen Lawrie: criticisms of the psychosis continuum
1) just because symptoms are continuously distributed in the general population doesn’t mean that schizophrenia and other psychoses are qualitatively indistinct from normal experiences.
2) there is no guarantee that a continuum is more valid and will aid progress. individual symptoms are less reliably identified compared to a multidimensional diagnosis. they vary in severity over time and may differ across contexts.
3) continuous measures are routinely employed in medicine when they can be simply and reliably assessed in one dimension. we don’t have such simple or easily used instruments… the prevalence of psychotic experiences vary across instruments.
4) established diagnostic categories are clinically useful. we also need to make dichotomous decisions such as whether or not to legally detain people.
pros and cons of categories
PROS:
- ease of use - description, communication, conceptualisation
- familiarity - typologies are used in the rest of medicine and biology
CONS:
- can distort perceptions of individuals, whether they are ill or well
- convey limited stereotyped information
pros and cons of continua
PROS:
- flexible measurement
- many biological variables are dimensional, like age
CONS:
- need to be simple (uni-axial) to be practical, like blood pressure
- many biological variables are categorical, like gender
CAARMS VS CAPE
- both measure APS
- CAARMS is a semi-structured interview with a clinician, lasts 2 hours
- CAPE is self-administered, lasting a few minutes
- it’s hard to reach homogeneity in answers - CAPE responses are poor predictors for clinician-rated APS. CAPE is asked in a college setting, whereas CAARMS is in a clinic.
- symptoms are not independent of their developmental and experiential context. the articulation of symptoms is not independent of the way in which it is elicited - despite their similar verbal formulation.
Josef Parnas: APS
- early diagnostic assessment requires not only a superficial symptomatic screening, but also an insight into the life of a patient in applying considerable psychopathological knowledge.
- “we are able to build up scales trivialising symptoms into phenomenological continue, but in this move the symptoms are emptied of their clinical validity”: when we reduce complex, subjective experiences (like those in schizophrenia or psychosis) to simplistic, numerical scales, we may be able to “measure” them—but in doing so, we lose the depth, nuance, and meaning that those experiences actually carry.
prodromal symptoms
- occur before the onset of FEP
- negative symptoms occur FEP for up to 5 years, and positive symptoms predate FEB for up to one year.
- the term prodromal is adopted in a retrospective view. it is not clinically suitable for intervention.
prospective intervention
= being able to identify individuals who will later develop psychosis within samples of high clinical risk
CAARMS 3 criteria
- APS (most frequent intake criterion, intermediate transition risk)
- BLIPS (very high transition risk)
- Genetic Risk and Deterioration Syndrome (GRDS, low transition risk)
attenuated psychotic symptoms (APS)
= “truman-like” experiences: feeling like the world is fake and fabricated, feelings of being controlled and spied on.
- these are felt in ARMS individuals who do not reach the delusional level - they are still able to criticize and dismiss these experiences
- included in the DSM-5 as the only symptom for ARMS psychosis
DSM-5 APS vs. clinical high risk state (CHR-P): key differences
1) the DSM-5 only includes APS to diagnose ARMS psychosis, not BLIPS or GRDS.
2) distress and disability are requirements for entry criteria for DSM-5 APS. these are not required to meet CHR.
reliability and validity within CAARMS
- reliability: ability of the tool to provide converging diagnosis across raters
- validity: ability of the tool to pick up true positives
- however, reliability for CAARMS is heavily reliant on proper training for raters. intensive training that is ongoing is required to achieve satisfactory reliability on the use of CAARMS.
FES vs. FEP
- the chance of relapse for people with FES is very high compared to that of those with short-lived psychotic episodes. so an initial diagnosis of FES is associated with the poorest longitudinal outcomes.
PSYCSCAN (2017)
is aiming at developing predictive tools to be used in clinical practice. the predictive algorithm will be based on a wide range of candidate predictors spanning from psychopathology to social demographic factors to neurobiology. ultimately, the outcome is the provability of the clinicians to be able to predict transition in individuals meeting CHR-P.
OASIS
= outreach and support in south london
- clinical service for identifying and treating help-seeking individuals aged 15-35 with at risk symptoms
OASIS 3 core clinical targets
1) reduce at risk symptoms and disability
2) prevent transition to psychosis
3) improve outcomes if psychosis develops
OASIS: discretion
- no obvious signage at the location. this:
1) respects privacy and acknowledges the stigma they may be subject to
2) separates CHR-P services from major mental health hospitals
3) improves accessibility
interventions for ARMS: what the evidence tells us
- we can delay the onset of psychosis
- we can’t prevent it
- we can’t maintain beneficial effects over long periods of time
- it seems that there are no effective treatments for APS, cognitive dysfunction, social functioning, negative symptoms in ARMS.
numbers needed to treat (NNT)
= the number of patients you need to expose to treatment in order to have at least one prevented from the outcome
- the higher it is the less effective your treatment in prevention
OASIS: costs
- the initial costs are high because of recruitment costs
- however, running costs are lower than standard services because OASIS aids in:
1) preventing psychosis
2) reducing admissions
3) reducing admission length
4) improving outcomes
