Are you sure? Delusion conviction moderates the behavioural and emotional consequences of paranoid ideas

Introduction Paranoid beliefs strongly impact behaviour and emotion: Most people with paranoid delusions engage in safety behaviours and a relevant minority even commits violent acts under the influence of delusional thoughts. The present study examined whether different levels of belief conviction modulate subsequent behaviour and emotion. To be able to control for important confounds, we set up an analogue study using nonclinical participants. Methods Participants were recruited from the general population (N=1935) and asked to fill out the Paranoia Checklist. Individuals had to imagine being persecuted by a secret service, whereby the level of subjective conviction was set at 20%, 40%, 60%, 80%, 90%, or 100%. Subsequently, participants had to estimate for 37 behavioural and emotional items how they might respond to this threat. Results Three quarters of the sample affirmed the presence of at least one paranoid idea from the Paranoia Checklist over the duration of a month. The level of belief conviction and paranoia was positively associated with behavioural and emotional consequences. Conclusions Our investigation suggests that a higher degree of belief conviction aggravates the behavioural consequences of persecutory beliefs in a linear fashion. The study is limited by its "what if" character and should be replicated with clinical participants. The study suggests that treatment approaches that aim to reduce overconviction may positively impact behaviour in psychosis.