earlier). Much of this has involved use of questionnaires or interviews to gauge rates of paranoid feeling in non-clinical samples. Better than this, though, would be observing people's actual paranoid interpretations unfolding in response to real events. Catherine Green and her team think they've found a way.
The researchers had 58 healthy participants sit in a room with a male experimenter and write about their journey to the lab that day (ostensibly as part of research into people's 'understanding of the causes of events'). Next, a male colleague knocked on the door and asked the experimenter if he could come outside for a moment. After the experimenter exited, the sound of male laughter was played for 35 seconds on speakers in the corridor.
What would you think if an experimenter left the room to talk to a colleague and then you heard laughter outside? Asked to explain these events, two of the participants thought the experimenter's departure had something to do with them; five of them thought the laughter was about them; and two participants thought both events were somehow connected to themselves. 'They laughed at something they read in my questionnaires,' one participant said. In all, 15.5 per cent of the healthy sample showed evidence of mild paranoia - what's known as 'an idea of reference' in which they misattributed self-relevance to the events. None of the participants showed more severe persecutory paranoia, and in fact 28 participants failed to notice the laughter.
'The current study illustrates that paranoid explanations for events can be elicited and assessed in a real life situation,' Green and her colleagues said. Questionnaires completed before and after the main part of the study showed that those participants who came up with more paranoid explanations also tended to score higher on 'trait' paranoia. However, they scored no higher on a measure of social avoidance and distress, which suggests their paranoid explanations were not merely a consequence of social anxiety. They did however score higher on interpersonal sensitivity and negative self-regard.
'The current data suggest that some of the processes considered central to clinical paranoia ... may also be operating at the milder end of the spectrum,' the researchers concluded, 'but the data raise questions as to what processes might be responsible for transition across the spectrum from ideas of reference to persecutory ideation.'
Green CE, Freeman D, Kuipers E, Bebbington P, Fowler D, Dunn G, and Garety PA (2011). Paranoid explanations of experience: a novel experimental study. Behavioural and cognitive psychotherapy, 39 (1), 21-34 PMID: 20846468
Further reading: Is paranoia increasing? Free Psychologist magazine article.