Symposium V: Theories and Mechanisms of Psychotic Symptoms Speakers
Rob Dudley
Eva Tolmeijer
Louise Isham
Daniel Freeman
Richard Bentall
Title: Visual Hallucinations: Why Do People See Things Others Do Not?
Abstract: Visual hallucinations (or visions) are associated with high levels of distress and disability yet there is little understanding of what leads to these experiences or how to help people affected by them. This talk will overview recent studies examining the occurrence of visions across non-clinical, ultra-high risk and first-episode groups, as well as people with psychosis and PTSD, demonstrating that visual hallucinations are common, and possibly represent a different pattern or constellation of experiences than reported by people with auditory experiences alone. Studies examining plausible candidate mechanisms (trauma, dissociation, imagery, worry, sleep) will be discussed.
Title: People's Ideas About the Causes of Feeling Unsafe Around Others.
Abstract: Although evidence supports multifactorial causation of persecutory beliefs, people’s own beliefs about causation are understudied. Therefore, views on causation were assessed in people with persecutory beliefs (n=115) using an open-ended interview. When assessing ideas about any causal factors, most reported a cause of which past traumatic experiences were most common (51%). When assessing ideas about specific causes, most reported more than one cause including personal (52%) and social environmental causes (48%) and past stressful and traumatic events (77%). Biological, natural environmental and spiritual causes were less frequently reported. The findings support that people with persecutory beliefs have a multifactorial view of causation and reveal that past traumatic experiences are most reported.
Title: Grandiose Delusions: Testing a Theoretical Psychological Model
Background: “I was completely convinced that I was God. I stepped off things and expected to fly. I tried walking on water and wouldn’t think through where I tried – places where getting out could’ve been challenging. It could’ve gone very very wrong if things had been slightly different. I could’ve got seriously hurt” – Sophie.
Grandiose delusions are a relatively common experience for individuals who have been given a diagnosis of affective or non-affective psychosis. Whilst at first glance they may appear to be a positive experience, they can also carry huge burden and significant harm can arise. It is critical therefore to have an effective intervention, but at present no theory driven targeted psychological intervention for grandiose delusions exists. The aim of the current research was to test a theory driven psychological model of harmful grandiose delusions which could then inform the development of a translational treatment.
Methods: Both clinical and non-clinical participants were asked to complete a range of self-report measures which assessed grandiosity and six putative psychological constructs hypothesised to drive grandiose beliefs. These were: the meaning in grandiose delusions, immersion behaviours, fantasy elaboration, anomalous experiences, reasoning biases, and mania. Where necessary, appropriate measures of key constructs were developed using exploratory and confirmatory factor analysis. Structural equation modelling was used to test the associations between each potential maintenance mechanism and grandiosity, and to test the total amount of variance in grandiosity explained by the model.
Outcomes: From March 2021 to March 2022, 798 patients with psychosis were recruited from NHS trusts and from August 2019 to November 2020, 13,323 non-clinical participants were recruited online. Six new measures were developed (the Grandiosity Meaning Measure (gram), the Grandiosity Meaning Measure - Sources (grams), the Immersion Behaviours Questionnaire (IBQ), the Thinking about Exceptional Experiences Questionnaire (TEEQ), the Qualities of Daydreaming Scale (QuoD), and the Subjective Harm from Exceptional Experiences Questionnaire). In this talk the findings relating to the associations between the hypothesised maintenance mechanisms and grandiose beliefs will be presented together with the implications for treatment development.
Title: Paranoia: 22 Social and Cognitive Processes
Abstract: The study was conducted to serve as a guide to the strengths and weaknesses of our current understanding of paranoia. 10 382 UK adults, quota sampled to match the population for age, gender, ethnicity, income and region, were assessed on a large number of cognitive and social processes. We examined the extent to which people felt that they had exaggerated fears of other people, how much of paranoia could be explained, and what might make paranoia or social anxiety particularly prominent for a person.
Title: Are There Common Factors in Delusions and Other Personally Significant Beliefs?
Abstract: A proliferation of research on delusions over the last thirty years has been constrained by lack of engagement with research literatures on other strongly held, personally significant beliefs such as religious beliefs, political beliefs and conspiracy theories. These share many features with delusions, for example, in terms of the certainty and emotion with which they are held and their resistance to disconfirmatory evidence and counter-argument. Indeed, there are many case studies of individuals whose beliefs have been disputed as delusional vs religious (the Morman murderers Dan and Ron Lafferty) or political (Anders Breivik). I will discuss some of the key similarities between delusions and these other kinds of beliefs, point to a key difference (that delusions are not coproduced in coalitions with other people and not proliferated within populations) and discuss a programme of research involving direct comparisons between these different kinds of beliefs.