The Neuropsychology

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The Neuropsychology of Psychosis
Vaughan Bell vaughan_at_backspace.org
School of Psychology, Cardiff University
(see notes page for references)
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Outline

• Defining psychosis.
• Traditional psychiatric model.
• Neuroanatomy.
• Neuropsychology.
• Neurological soft signs.
• Mental fever view.
• Continuum model of psychosis.
• Outcome predictors.

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Defining Psychosis

• Psychosis is often discussed as if it is a well
  defined unitary psychological concept.
• In fact, it is a fairly vague term used to
  classify a set of symptoms, and is not in itself,
  a diagnostic category.
• Each symptom definition has its own internal
  ambiguities and inconsistencies.

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Psychotic Symptoms

• Hallucinations In any sensory modality, although
  auditory hallucinations (voices) are common.
• Delusions Defined as fixed, false, incorrigible
  beliefs, sometimes bizarre, often persecutory.
• Thought disorder Derailment, flight of ideas,
  clanging, insertion, blocking, neologisms,
  echolalia.
• Lack of insight Significance / origin of
  symptoms, implausibility of experience. Can
  include inappropriate reaction / refusal of
  treatment (!).
• Symptom diagnosis involves significant subjective
  components, or is based on incoherent
  definitions.

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Aetiology of Psychosis

• Traditionally linked to
• Schizophrenic spectrum disorders
• Affective disorders
• Organic syndrome disorders (commonly dementia)
• Although may arise after almost any sort of
  illness, injury or drug (inc. medication) use.
• Cases on PubMed can be found following AIDS,
  intensive care, malaria, leprosy, mumps,
  steroids, flu, diving, painting...

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Aetiology of Psychosis

• However, the diagnosis of schizophrenia, relies
  on the presence of psychotic symptoms.
• This has confused the picture, as many studies of
  psychosis are actually on schizophrenic
  psychosis.
• This is confusing as schizophrenia seems to
  involve specific neuropsychological deficits
  above and beyond those associated with the
  presence of psychosis per se (Tsuang et al,
  2000).
• Ive attempted to focus on studies that look at
  non-specific psychosis, rather than schizophrenic
  psychosis only.

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Traditional Psychiatric Model

• Traditionally, psychosis has been seen as a
  qualitatively different state from normal mental
  functioning.
• It is seen as a disorder or pathological in
  nature.
• According to Johns and van Os (2001), this view
  additionally relies on
• symptom factors such as intrusiveness, frequency
  and co-morbidity.
• personal and social factors such as coping,
  illness behaviour, societal tolerance, resultant
  disability.

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Neuroanatomical Abnormalities
Probably the first neuroimage of psychosis.
Patient with paranoid schizophrenia. (Moore et
al, 1935)
Pneumoencephalogram showing enlarged sulci.
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Neuroanatomical Abnormalities

• It is now certain that schizophrenia involves
  structural changes to the PFC, corpus callosum
  and ventricles. (Wolkin Rusinek, 2003).

• A recent study by Pantelis et al (2003) showed
  that psychosis per se involves grey matter
  changes.
• Baseline MRI scan of 75 people with prodromal
  signs of psychosis.
• 23 developed frank psychosis at 1 year follow up,
  baseline scans were compared.
• Rescanned 10 individuals with frank psychosis and
  compared re-scan with baseline.

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Pantelis et al (2003)
Areas of grey matter reduction in psychosis.
right temporal inferior frontal cortex cingulate
L
R
Baseline comparison example
left medial temporal left orbitofrontal cingulate
cerebellum
R
L
Follow-up comparison example
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Subjective Deficits

• Prodromes may self-perceive subtle cognitive and
  perceptual aberrations predictive of later
  psychosis in schizophrenia (Klosterkötter et al,
  2001).
• Hambrecht et al (2002) prodromes who subjectively
  experience cognitive deficits (perception,
  cognition, stress reactivity)
• ...may also be characterised by objectively
  measurable disturbances.
• Particularly attention, verbal / visual memory
  and verbal fluency.
• Although these were significantly less severe
  than patients who had already developed
  schizophrenia.

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First Episode Psychosis

• Friis et als (2002) factor analysis of cognitive
  function in first episode psychosis found five
  main areas of deficit
• working memory
• verbal learning
• executive function
• impulsivity
• motor speed
• Group means were well below normal.
• But WM, VL and EF were weakly correlated,
  suggesting a great deal of individual variation.

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Diagnostic Comparison

• Verdoux and Liraud (2000) compared neuropsych
  performance in schizophrenia, non-schizophrenic
  psychosis, bipolar and major depression.
• Only memory performance was significantly
  associated with diagnostic group.
• Even when controlled for treatment time,
  substance use, number of hospitalisations.
• So, no significant difference for psychosis per
  se.
• But they conclude a continuum of impairment may
  exist between schizophrenia, other psychosis and
  mood disorders.

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Verdoux and Liraud (2000)
N 20
N 29
N 33
N 19
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Duration of Untreated Psychosis

• However, the duration of untreated psychosis does
  not seem to be related to cognitive deficits or
  changes in brain morphology.

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Neurological Soft Signs

• Characterised by abnormalities in motor, sensory
  and integrative functions, which do not reflect
  localised brain dysfunction.
• Cuesta et al (2002) used the Neurological
  Evaluation Scale (NES) to assess NSS in psychotic
  patients.
• NSSs were more predictive of cognitive impairment
  in psychosis than psychopathological dimensions.
• Particularly useful for patients with severe
  communication disturbances as relies less on
  verbal abilities.

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Mental Fever View

• Tsuang et al (2000) argue that psychosis is the
  fever of mental illness - a serious but
  non-specific indicator.
• Several lines of argument back their case
• Many disorders can cause psychosis.
• Relatives of persons with psychotic illness can
  often show similar neurocognitive / psychosocial
  deficits without being psychotic themselves.
• Neurocognitive / psychosocial deficits may be
  present before the onset of psychosis.
• Dubious evidence for psychosis neurotoxicity.

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Continuum Model

• There is now increasing evidence that the
  qualitative distinction between psychosis and
  normality is insufficient.
• Johns and van Os (2001) argue for a continuum
  between frank psychosis and more mundane views of
  reality.
• Verdoux and van Os (2002) showed that unusual
  experiences (unusual perceptions, anomalous
  beliefs) are prevalent throughout the population.

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Continuum Examples

• Hallucinations
• Ohayon (2000) 27 reported daytime hallucinations
  (N 13,057).
• Tien (1991) 10 - 15 hallucination prevalence
  (N18,572)
• Delusions
• Eaton et al (1991) Bizarre delusions 2, paranoid
  / special power delusions 4-8.
• Peters et al (1999a) Delusional ideation scale,
  10 of healthy group scored above psychotic mean,
  ranges were similar for both groups.

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Continuum Examples

• Thought Disorder
• Spence (1996) argues for a continuum between
  thought insertion and everyday spontaneous
  thought.
• Cox and Cowling (1989) 50 believe in thought
  transference between two people.
• Lack of insight
• Botovnick and Cohen (1998) People report feeling
  a touch in a hand they know is rubber.
• Kuhn (1962) Scientists may hold on to beliefs
  despite overwhelming evidence to the contrary.

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Continuum Examples

• Peters et al (1999b) have reported equivalent
  levels of anomalous beliefs in people from New
  Religious Movements and psychotic inpatients.
• However, NRM followers are much less distressed
  and pre-occupied by their beliefs than patients.

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Hemispheric Asymmetries

• Experimental studies on schizophrenic patients
  seem to suggest that the usual LH advantage for
  linguistic processing in schizophrenia is lost.
• Crow (1997) argues that schizophrenia is a
  dimensional trait that results from a reduced
  left hemisphere dominance for language.
• And argues that schizophrenia is the price we pay
  for an evolutionary adaptation for language which
  requires left hemisphere specialisation.

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Hemispheric Asymmetries

• However, functional asymmetries (greater RH
  activation) also exist for non-pathological
  continuum states.

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Continuum View

• All of this suggests that the anomalous
  experience component of psychosis may be variably
  distributed throughout the population.
• However, Peters et al (1999a) study on New
  Religious Movements shows that there must be
  something else which mediates how distressing
  this becomes.
• Perhaps a combination of attribution and
  aetiology.

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Outcome

• van Os et al (1999) aimed to identify underlying
  dimensions in psychopathology and relate to
  outcome.
• Worst outcome first
• early / insidious onset and affective flattening
• bizarre behaviour / affect, catatonia, poor
  rapport
• positive psychotic symptoms
• manic symptoms
• Symptoms associated with cognitive slowing seem
  to have worse outcome.

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Outcome

• Verdoux et al (2002) assessed cognition at
  baseline for first admission psychosis.
• Assessed social and clinical outcome at 6 month
  intervals for a further two years.
• Visual and verbal memory performance was
  correlated with outcome over the two years.
• Poorer performance was correlated with higher
  risk of psychotic symptoms and rehospitalisation.
• This was after controlling for medication
  adherence.

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Outcome

• Silverstein et al (1997) unfavourable clinical
  outcome associated with marginal changes in
  neuropsychological performance.
• Good outcome associated with neuropsychological
  improvement.
• They suggest an alternative effect, where
  neuropsychological improvement may require a
  stable period of psychosocial recovery.

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Implications

• Psychosis is a rather vaguely defined concept and
  often not clearly delineated from schizophrenic
  symptomology in the literature.
• However, more exacting studies suggest that it is
  associated with significant neuroanatomical and
  functional changes.
• Memory performance and neurological soft signs
  seem to be particularly relevant.

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Implications

• Psychosis like experience may exist on a
  continuum.
• Higher levels of psychosis-like or anomalous
  experience may be related to increased right /
  decreased left hemisphere activation.
• Disability and outcome in psychosis seem to be
  significantly associated with neuropsychological
  performance.
• Especially if related to schizophrenia.