Do paranoid delusions exist on a continuum with subclinical paranoia? A multi-method taxometric study

Background There is widespread interest in whether psychosis exists on a continuum with healthy functioning. Previous research has implied that paranoia, a common symptom of psychosis, exists on a continuum but this has not been investigated using samples including both patients and non-patients and up-to-date taxometric methods. Aim To assess the latent structure of paranoia in a diverse sample using taxometric methods. Method We obtained data from 2836 participants, including the general population as well as at-risk mental state and psychotic patients using the P-scale of the Paranoia and Deservedness Scale. Data were analysed using three taxometric procedures, MAMBAC, MAXEIG and L-MODE (Ruscio, 2016), and two sets of paranoia indicators (subscales and selected items from the P scale), including and excluding the patient groups. Results Eleven of the twelve analyses supported a dimensional model. Using the full sample and subscales as indicators, the MAMBAC analysis was ambiguous. Overall, the findings converged on a dimensional latent structure. Conclusions A dimensional latent structure of paranoia implies that the processes involved in sub-clinical paranoia may be similar to those in clinical paranoia

A randomised controlled trial of a brief online mindfulness-based intervention on paranoia in a non-clinical sample

Paranoia is common and distressing in the general population and can impact on health, emotional well-being and social functioning, such that effective interventions are needed. Brief online mindfulness-based interventions (MBIs) have been shown to reduce symptoms of anxiety and depression in non-clinical samples, however at present there is no research investigating whether they can reduce paranoia. The current study explored whether a brief online MBI increased levels of mindfulness and reduced levels of paranoia in a non-clinical population. The mediating effect of mindfulness on any changes in paranoia was also investigated. One hundred and ten participants were randomly allocated to either a two week online MBI including 10 minutes of daily guided mindfulness practice or to a waitlist control condition. Measures of mindfulness and paranoia were administered at baseline, post-intervention and one-week follow-up. Participants in the MBI group displayed significantly greater reductions in paranoia compared to the waitlist control group. Mediation analysis demonstrated that change in mindfulness skills (specifically the observe, describe and nonreact facets of the FFMQ) mediated the relationship between intervention type and change in levels of paranoia. This study provides evidence that a brief online MBI can significantly reduce levels of paranoia in a non-clinical population. Furthermore, increases in mindfulness skills from this brief online MBI can mediate reductions in non-clinical paranoia. The limitations of the study are discussed