The Neuropsychology of Psychosis

1. The Neuropsychology of Psychosis Vaughan Bell vaughan@backspace.org School of Psychology, Cardiff University (see notes page for references)

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

3. 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.

4. 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.

5. 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...

6. 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). • I’ve attempted to focus on studies that look at non-specific psychosis, rather than schizophrenic psychosis only.

7. 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 andvan 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.

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

9. Neuroanatomical Abnormalities • It is now certain that schizophreniainvolves 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.

10. 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

11. 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.

12. First Episode Psychosis • Friis et al’s (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.

13. 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.

14. Verdoux and Liraud (2000) N = 20 N = 29 N = 33 N = 19

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

16. 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.

17. ‘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.

18. 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.

19. Continuum Examples • Hallucinations: • Ohayon (2000) 27% reported daytime hallucinations (N = 13,057). • Tien (1991) 10 - 15% hallucination prevalence (N=18,572) • 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.

20. 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.

21. 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.

22. 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.

23. Hemispheric Asymmetries • However, functional asymmetries (greater RH activation) also exist for non-pathological ‘continuum’ states.

24. 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.

25. 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.

26. 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.

27. 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.

28. 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.

29. 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.