Author's reply

All too often the presence of paranoid thinking has only been given significance in relation to diagnosing illness. It has been viewed as a symptom that leads to a diagnosis and that, more or less, is the end of it. An alternative view is that the experience itself should take centre stage. ^1,2 Persecutory thinking is important to understand and treat in its own right. Evidence is accumulating that paranoid ideation is on a spectrum of severity in the general population. Our study concerned the milder end of the experience, but it is of interest for understanding clinical paranoia.

Braithwaite's suggestion of an ‘erroneous use of the word paranoia’ contains an example of the problems of the traditional diagnostic approach to psychosis. The history of the term paranoia was originally described by Sir Aubrey Lewis. ³ Lewis began his review of the fluctuations in the use of the word by noting that Hippocrates applied it to describe the delirium of high fever. Braithwaite does not wish to revert to this early use of the term, but takes a very traditional psychiatric delusion definition. This view is that paranoia only refers to a fixed false belief that the person cannot conceive of as a symptom. The problems with such a view of delusions have been laid out in many places over many years. ⁴ A simple illustration of the difficulties is provided by asking: how strongly does the idea have to be held to be delusional (100% conviction, 99%, 90%, etc.)? Studies show that about a half of people with clinical delusions can conceive that they might possibly be mistaken. The empirical evidence indicates that delusions are complex multidimensional experiences that are not easily dichotomised into being present or absent. The other aspect of the objection is that paranoia can refer to all delusion subtypes. Undoubtedly, psychiatric researchers have used the term variably. In our work the definition of the experience being studied – called persecutory or paranoid ideation – is made explicit for readers, based on an earlier review. ⁵ Therefore, the most salient point is that the phenomenon being explained is always clear.

Ghosh focuses on one of the predictors of paranoia in virtual reality: previous gaming experience. He provides helpful comment on the association. However, there are perhaps more interesting aspects of the study for psychiatry. Persecutory ideation in virtual reality was predicted by everyday occurrences of paranoid thought, suggesting that the results are more generally applicable to understanding the paranoia spectrum. Therefore the identification of a number of emotional and cognitive processes (e.g. worry, self-esteem, cognitive flexibility) that predict paranoia is where the interest should lie for clinical practice. These factors could be changed and thereby may lead to reductions in persecutory ideation. More broadly, the study highlights the large affective component to paranoid experience. It is hoped that these aspects of the study also generate interest and debate.