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Summary articles and learning goals Behavioural Disorders 2019
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Learning goals problem 1- What is the psychosis-proneness-persistence-impairment model?
- What are psychotic symptoms according to the DSM5?
- What kind of environmental causes can trigger clinical psychosis?
- Can you get sudden psychosis or does it build over time?
- What are the different approaches? (pros and cons)
Problem 1 Articles
The continuity of psychotic experiences in the general population ~ Johns and van Os
Abstract
The diagnosis of schizophrenia is made according to current diagnostic systems of DSM-IV on the
characteristic of positive and negative symptoms.
The traditional medical model assumes a categorical view of the schizophrenia syndrome and its core
symptoms, in which differences between psychotic symptoms and their normal counterparts are
considered to be qualitative.
An alternative, dimensional approach assumes that schizophrenia is not a discrete illness entity, but
that psychotic symptoms differ in qualitive ways from normal experiences and behaviours.
➔ This paper reviews evidence for the continuity of psychotic symptoms with normal
experiences, focusing on the symptoms of hallucinations and delusions.
The continuity hypothesis: diseases or distributions?
The psychosis phenotype is generally thought of as a dichotomous entity that can be identified by
applying certain operationalised criteria. Contrary to the situation in clinical practice, disease at the
level of the general population generally exists as a continuum of severity rather than as an all-or-
none phenomenon.
Psychosis continuum views
The hypothesis that psychosis exists in nature as a distribution of symptoms is not as bold as it may
seem. The supposition of a psychosis continuum does not necessarily imply that there is a continuum
of disorder. It can be surmised that the “real” distribution of psychosis most likely lies somewhere
between that of the dichotomous one and the continuous one depending on the degree of
interaction between the different causes and differences in their effect size, always assuming that
psychosis is subject to more than one causal influence.
Assessment of the distribution of psychosis
Two approaches: the first approach is to measure in the general population the same symptoms that
are seen in patients with psychotic disorders. The implicit assumption of this approach is that
experiencing symptoms of psychosis such as delusions and hallucinations is not inevitably associated
with presence of disorder. The second approach is different, and assumes that in the sub-disorder
range along the continuum, the expression of the trait is attenuated and takes on the form of
“schizotypal” signs and symptoms. The choice of instruments greatly influences the resulting
distribution in prevalence studies. The distribution will also be influenced by the symptom dimension
that the instrument is aiming to capture, for example positive or negative dimensions.
Are there findings supporting a psychosis continuum?
Several research findings can be brought forward to support the hypothesis of a psychosis
continuum. Prevalence of symptoms of psychosis: the distribution of schizotypal signs is highly
dependent on the instrument used. The distributions of variably-defined schizotypy signs are
themselves difficult to interpret in the absence of associations with third aetiological, social
impairment or treatment variables.
,There are normal individuals who experience hallucinations under no special circumstances, and
surveys have shown that more people experience hallucinations than come into contact with medical
or psychiatric services. A few studies have attempted to estimate the prevalence of hallucinatory
experiences in the general adult population. However, as witch schizotypy research, variation in
reports of hallucinations partly reflects the different assessment measures used, some of which also
assess attenuated anomalous experiences in addition to the hallucinations seen in psychosis.
Normal individuals can hold overvalued and delusional ideas.
The studies reviewed above provide evidence for the continuity of the individual phenomena of
hallucinations and delusions. However, in patients with psychotic disorder, the positive symptoms of
hallucinations and delusions typically occur together. Symptoms and underlying psychological
mechanisms of psychosis occur as part of a continuous, albeit very skewed, distribution that shows
only very partial overlap with clinical disorder.
Similarity in underlying dimensional representation
The above findings suggest that the positive symptoms of psychosis are prevalent in the general
population, but give little information about other symptoms and how different symptoms might
cluster together. There is growing evidence from factor analytical studies that schizotypy is a
multidimensional construct composed of three, and possibly four, dimensions: a positive dimension,
a negative dimension, a conceptual disorganisation dimensions, and an asocial/non-conformity
dimension.
Psychosis may exist as a continuum of variation along various comorbid symptom dimension.
(NIET ALLES STAAT ERIN)
CONCLUSION
Several independent sources of evidence indicate that psychosis exists as a continuum of experiences
with a distribution in the general population. The implications of this evidence for the diagnoses,
aetiology and treatment of psychotic states that are associated with need for care are increasingly
apparent. The encouraging results of new therapeutic approaches that are characterised by a
dimensional view an normalising rationale, suggest that it may be rewarding to further incorporate
the notion of a psychosis continuum in scientific research and clinical practice.
Can neuroscience be integrated into the DSM-5 ~ Hyman
Abstract
The diagnosis of mental disorders has been based on clinical observation. The diagnostic and
statistical manual of mental disorders and the international classification of disease, the manuals that
specify the diagnoses and the criteria for making them, are currently undergoing revision. It is thus
timely to ask whether neuroscience has progressed to the point that the next editions of these
manuals can usefully incorporate information about brain structure and function.
Example schizophrenia
A great deal of research supports the division of the symptoms of schizophrenia into three clusters:
positive, negative and cognitive symptoms that might reflect different aspects of the
pathophysiology and possibly different genetic risk factors, and that respond differentially to current
antipsychotic medications.
In their classic adoption studies of schizophrenia Kety et al. found that the biological families of
individuals with schizophrenia contained members who did not have psychotic symptoms, but who
nevertheless exhibited less dramatic schizophrenia-like symptoms such as social isolation,
suspiciousness, eccentric beliefs and magical thinking. When such symptoms are chronic and
impairing, the DSM-IVTR calls for the diagnosis of schizotypal personality disorder. Oddly, this is
classified as a personality disorder, and is not grouped with schizophrenia, even though subsequent
studies have confirmed a genetic relationship between the two.
,In the future, it might be possible to develop a meaningful quantitative scale based on grey-matter
thickness, perhaps in some region of the prefrontal cortex. Insofar as dimensions could be measured
objectively using cognitive tests in the laboratory or through structural and functional neuroimaging,
such an approach would improve diagnostic reliablitly as well as address concern about validity.
A second possible approach is to ‘deconstruct’ DSM-IVTR disorders such as schizophrenia into related
symptom clusters. This would permit investigators to focus on those symptoms for which there are
promising neurobiological leads. In the case of schizophrenia, it might be possible to make
substantial progress in research on the cognitive symptoms without having to focus on the neural
underpinnings of delusions or hallucinations. An approach as this clearly has limitations for nosology.
A focus on the structural and functional abnormalities in the circuitry that underlies the cognitive
functions that are abnormal in schizophrenia will not, by itself, provide a complete picture of a
disorder that also has symptoms such as hallucinations and avolition.
The third possible approach to the classification of psychiatric disorders is to think in terms of larger
spectrum disorders. For the schizophrenia spectrum, this might include at least schizotypal
personality disorder and the non-affective psychoses in the DSM-IVTR.
CONCLUSION
It is probably premature to bring neurobiology into the formal classification of mental disorders that
will form the core of the DSM-V. However, it is not too early to use neurobiology as a central tool to
rethink the current approach to mental disorders and to begin some careful experiments that could
liberate science from the unintended consequences of reifying the current diagnoses that probably
do not mirror nature. The goal of creating larger groupings is to encourage re-analysis in the way I
described above for the schizophrenia spectrum. I hope in addition that mechanisms can be created
to post and evaluate relevant new findings, be they genetic markers or neuroimaging results, and
that there can be interim processes to adjust the experimental criteria long before it is time to start
thinking about DSM-VI.
A comprehensive review of auditory verbal hallucinations: lifetime prevalence, correlates and
mechanisms in healthy and clinical individuals ~ de Leede-Smith and Barkus
Abstract
This review will examine the presentation of auditory hallucinations across the life span, as well as in
various clinical groups.
The biopsychosocial model provides a system where triggers, maintaining and moderating factors can
be incorporated informatively. The domains interact with one another on a causal and mechanistic
level, demonstrating the etiological complexity of AVH at any point along the lifespan and in both
clinical and non-clinical groups. Factors can be conceptualized as background factors which are
stable, may be biologically underpinned, and provide a backdrop against which other factors interact.
These interacting factors can be mechanisms or triggers, the former contributing to maintenance and
the latter initiating onset
Prevalence of AVH and related phenomena
AVH are at their most prevalent in diagnosed psychotic disorders such as schizophrenia and
schizoaffective disorder but also occur in other disorders including bipolar disorder, substance
intoxication and organic dementias.
Children: The presence of an imaginary companion could be part of the normal development and
sociability of the child, however further research in this area is warranted to understand their
developmental relevance and long term outcomes.
, Adolescence and adulthood: studies examining the prevalence of non-clinical auditory hallucinations
in adolescents are limited compared to child and adult investigations. This is unusual given that the
onset for prodromal symptoms for psychosis and other mental health disorders often emerge during
mid- to late adolescence. Adolescence is the onset of a series of rapid changes in hormones and brain
development. From a biopsychosocial perspective these changes are often cited as a possible
explanation for the initiation and presentation of mental health symptoms which can evolve into
schizophrenia. The range of neurological, emotional and social changes which take place in
adolescence may put predisposed individuals in a heightened state of vulnerability to
psychopathology.
Persistence of AVH
Under the biopsychosocial framework of AVH development, it is evident that there are certain
mechanisms which contribute to the maintenance of hallucinatory experiences past the stage of
initial development. A specific factor associated with the persistence of hallucinatory experiences in
children is the formation of secondary delusions. Delusional ideation is more likely to occur under
situation of affective dysregulation. When states of anxiety, depression and stress interact with pre-
existing hallucinatory phenomena affective disturbances can culminate to create delusional
pathology.
In childhood the incidence of AVH has been reported to be a risk for a later transition to
schizophrenia. Besides psychosis the presence of childhood AVH are concurrently associated with
depression and anxiety.
The persistence-impairment model suggests that the progression to increased impairment from
psychotic-like experiences occurs at a point where the individual is exposed to sufficient environment
stressors. Persistence of AVH in adolescence has been associated with increasing depression, general
psychopathology, delusional ideation and need for care.
The Clinical Staging model distinguishes residual symptoms or early signs in order for them to be
detected more readily before progression to full psychopathology. The key factors implicated would
be the persistence of the AVH, the presence of distress, other mental health symptoms and any type
of help seeking behaviour.
From the evidence considered so far, it appears that non-clinical AVH become pathological when
they persist, lead to the development of other symptoms and causes distress and functional
impairment. Accordingly it can be argued that they do lie on a continuum of risk, ranging from
normal healthy experiences, through to pathological psychotic.
Comparison of clinical and non-clinical hallucinations in adult populations
Compared to AVH in schizophrenia, non-clinical AVH have been found to occur much less frequently,
and usually occur after specific conditions such as high stress or sleep deprivation. There are also a
number of cognitive capacities which also distinguish clinical and non-clinical voice hearers, both of
whom are distinguishable from healthy volunteers. A cognitive factor that has been found to
distinguish clinical from non-clinical AVH is inhibitory control.
Compared to healthy non-voice hearers, higher levels of negative affect are common to AVH in
schizophrenia and otherwise healthy voice hearers both during hallucinations and also when
hallucinations are not present. This is suggestive of emotional arousal possibly premeditating
hallucination onset, or being a factor involved in the occurrence of these perceptual experiences.
Anxiety has the most predictive power for the predisposition to hallucinate in non-clinical groups,
over and above depression and stress ratings.
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