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Understanding the psychological and social causes of psychotic symptoms

One of the main reasons people seek psychiatric treatment for psychotic experiences is because they become very distressed by them. A significant factor contributing to this distress may be the internalisation of societal stigma, however attempts to reduce this stigma have so far not been successful, and there is evidence that mainstream mental healthcare can sometimes make this worse. We also know that psychotic experiences in the general population, although much more common than once thought, are associated with a heightened risk of suicidal ideation and self-harm, and that a major risk factor for psychotic experiences is early trauma and adversity. How trauma leads to psychotic experiences remains unclear, and we and many other research groups are conducting research to address this question.


It seems clear, then, that psychological distress can be both a cause and a consequence of psychotic experiences, and that both the experiences and the distress they cause can reduce a person’s ability to experience a recovery that is meaningful to them, as well as pose a risk to their autonomy. Reducing societal stigma, improving psychiatric care, and reducing early adversity is therefore essential, however there also remains a pressing need to identify the full range of modifiable causes of psychosis, particularly if wish to hasten the development of more effective therapies. In Scotland, there has already been considerable investment in research on the genetic and biological causes of psychosis, therefore a major focus of the Psychosis, Recovery and Autonomy Research Unit is to increase the quantity and quality of research being carried out to identify modifiable psychological and social causes. Completed and ongoing research in this area is outlined below:

Carmichael, Goodall, Harper & Hutton (ongoing)

  • This study is examining whether trauma contributes to persecutory delusions via the formation of negative self-schemata.

  • We are also piloting a novel interview-based assessment of schemata, using this to validate responses to a widely-used questionnaire measure of this outcome.

Carmichael, Goodall, Harper & Hutton (ongoing)

  • This systematic review and meta-analysis is examining the extent to which specific forms of childhood trauma (sexual, physical and emotional abuse; physical and emotional neglect) are related to paranoia severity in people with persecutory delusions, taking into account study and outcome quality.

  • The protocol for this review is available here.

Davis & Hutton, (in prep)


  • This cross-sectional study of the general population (N=156) examined whether  early trauma and adversity contributes to paranoia via increasing fears about death.

  • Fear of death did not explain the association between early adversity and paranoia. An unexpected finding was that fear of death was negatively associated with both paranoia and subclinical psychotic experiences

Michalska, Rhodes, Vasilopoulou & Hutton (2017)


  • We did a systematic review and meta-analysis of 13 studies (N=15,647) which reported data on the relationship between psychosis and loneliness.

  • We found loneliness was significantly associated with psychosis across these studies, explaining about 10% of the variance.

  • The paper is available here.


Michalska, Rhodes, Murray & Hutton, (in prep)


  • This experimental study tested whether temporary induction of mild feelings of loneliness in healthy older adults (N=62) caused an increased tendency to hear words in ambiguous speech or see faces in ambiguous stimuli.

  • Although we did not detect an increase in loneliness following the induction, participants allocated to the lonelines group did hear more words than those allocated to the control condition, suggesting that the induction triggered some process that led to biases in perception that predispose to auditory hallucinations.

Murphy, Bentall, Freeman, O’Rourke & Hutton, (in prep)


  • We did the first systematic review and meta-analysis of the influential yet contested theory that persecutory delusions are caused by a bias towards holding others responsible for negative events, which protects their low ‘implicit’ self-esteem from reaching conscious awareness.

  • We included data from 63 studies (N=5193; participants with psychosis N=3524).

  • The results will shortly be submitted for publication.

Woodrow, Karatzias, Harper, Fleming & Hutton (ongoing)

  • This randomised controlled trial will use 'ecological interventionist-causal' methodology to examine whether a therapeutic approach designed to improve emotion regulation will reduce paranoia in people with psychosis. This novel experimental approach to understanding the causes of psychosis will employ 'real-time' experience sampling to examine the effects of the intervention and the relationship between emotion regulation improvements and paranoia.

Woodrow, Karatzias, Harper, Fleming & Hutton (ongoing)

  • This large study of the general population (Target N = 400) seeks to identify the key psychological and emotional mediators of the trauma-psychosis association. The first stage (N=200) will involve exploratory factor analysis, and the second (N=200) will involve confirmatory factor analysis of the previously observed model.

  • The first stage of data collection is nearly complete, and the exploratory analysis is due to commence soon.

  • The website for the study is available here.

Woodrow, Karatzias, Harper, Fleming & Hutton (ongoing)

  • This systematic review is synthesising the existing literature on the psychological and emotional mediators of the trauma-psychosis relationship, taking into account study quality and strength of evidence for causality.

  • Searches, quality assessment and initial syntheses have been completed.

  • The protocol for this review is registered here.

In addition to our work trying to understand the causes of psychotic symptoms, we are also researching the safety and effectiveness of existing treatments, developing ways to thoroughly assess adverse effects of therapy, and developing new interventions.

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