Tuesday, 6 October 2020

Affective Instability and Paranoia

This post is by me (Lisa Bortolotti), summarising a paper I wrote with Matthew Broome on how affective instability may be a causal factor in paranoia. It was published in a special issue of Discipline Filosofiche on Philosophical Perspectives on Affective Experience and Psychopathology, edited by Anna Bortolan and Alessandro Salice.


Matthew Broome

Most accounts of paranoia rely on cognitive biases and perceptual anomalies. However, recent empirical research has shown that affective instability may play an important role. 

What is affective instability? Unexpected changes of mood include emotional dysregulation, lability, impulsiveness, and swings. Collating the main overlapping dimensions, definitions, and their measurement scales, a recent systematic review proposed that affective instability is “rapid oscillations of intense affect, with a difficulty in regulating these oscillations or their behavioural consequences” (Marwaha et al. 2013). 

How does affective instability impact on paranoia? In large samples, recent research has identified some interesting correlations and potential causal relationships: affective instability predicted not only the onset of paranoid ideation, but also its maintenance. This association between affective instability and paranoia remains after controlling for numerous confounds, and affective instability does not impact in the same way on other phenomena. For instance, no association is found between affective instability and auditory hallucinations.

Affective instability might explain some of the connections between childhood sexual abuse and psychosis (Marwaha et al. 2014) and between bullying, psychotic disorder and psychotic symptoms (Catone et al. 2015), with bullying doubling the risk of paranoia.

How should we think about the causal role that affective instability plays in relation to paranoia? There are several options we examine in the paper:

  1. the causal link between affective instability and paranoia is biological, with a single mechanism causally responsible for both affective instability and paranoia.
  2. the causal link between affective instability and paranoia is mediated by behavioural effects. 
  3. the causal link between affective instability and paranoia is mediated by the way the person appraises the world or appraises the self. 
  4. the causal link between affective instability and paranoia is determined by the person’s lifestyle rather than the person's behaviour.

Lisa Bortolotti


Acknowledging and further examining the causal contribution of affective instability to paranoia is not incompatible with the main models of delusion formation currently discussed in the empirical and philosophical literature.

It has also significant implications for prevention and treatment. For instance, instability of mood would need to be addressed in the attempt to prevent psychotic episodes. People at risk of psychosis would need to be supported in implementing lifestyle changes that are conducive to an improvement in emotional regulation, such as sleeping better.

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