Concomitants of paranoia in the general population D. Freeman 1 *, S. McManus 2 , T. Brugha 3 , H. Meltzer 3 , R. Jenkins 1 and P. Bebbington 4 1 King’s College London, Institute of Psychiatry, London, UK 2 National Centre for Social Research, London, UK 3 Department of Health Sciences, University of Leicester, Leicester, UK 4 Department of Mental Health Sciences, University College London, London, UK Background. Paranoia is an unregarded but pervasive attribute of human populations. In this study we carried out the most comprehensive investigation so far of the demographic, economic, social and clinical correlates of self- reported paranoia in the general population. Method. Data weighted to be nationally representative were analysed from the Adult Psychiatric Morbidity Survey in England (APMS 2007 ; n=7281). Results. The prevalence of paranoid thinking in the previous year ranged from 18.6 % reporting that people were against them, to 1.8 % reporting potential plots to cause them serious harm. At all levels, paranoia was associated with youth, lower intellectual functioning, being single, poverty, poor physical health, poor social functioning, less perceived social support, stress at work, less social cohesion, less calmness, less happiness, suicidal ideation, a great range of other psychiatric symptoms (including anxiety, worry, phobias, post-traumatic stress and insomnia), cannabis use, problem drinking and increased use of treatment and services. Conclusions. Overall, the results indicate that paranoia has the widest of implications for health, emotional well- being, social functioning and social inclusion. Some of these concomitants may contribute to the emergence of paranoid thinking, while others may result from it. Received 23 March 2010 ; Revised 23 July 2010 ; Accepted 25 July 2010 ; First published online 24 August 2010 Key words : Delusions, epidemiology, paranoia, schizophrenia. Introduction The paranoia spectrum is of special interest. Its severe end, persecutory delusion, is taken as a key sign of schizophrenia. Studying the milder variants, mistrust and suspicion, sheds light on societal issues, such as individual well-being and social cohesion. The few reported studies have identified correlates in common for mistrust, suspicion, persecutory ideation and de- lusions, suggesting that they are related experiences (e.g. Combs et al. 2006 ; Vermissen et al. 2008 ; Freeman et al. 2010 b). The pervasiveness of paranoia has been firmly es- tablished over recent years. Many people have a few paranoid thoughts, and a few people have many. Epidemiological and experimental studies indicate that paranoid thinking may be a regular experience in one out of three people from the general population, and at least one in twenty have a persecutory delusion during their lifetime (e.g. Johns et al. 2004 ; Freeman et al. 2008 b ; Rutten et al. 2008). Even low-level, fleeting suspicious thoughts are distressing (Freeman et al. 2005). This high prevalence is unsurprising if paranoia arises from the normal everyday decision making about whether to trust or mistrust. Few large epidemiological studies have examined the correlates of paranoia, but two are noteworthy. The assessment of trust in other people is considered as a central component of social cohesion or ‘ social capital ’ (Coleman, 1988 ; Putnam, 1995). Kawachi et al. (1997) in the USA used survey data from the late 1980s obtained from 7654 individuals across 39 states. The key items for assessing levels of trust were : ‘ Do you think most people would try to take advantage of you if they got a chance ? ’, ‘ Generally speaking, [would you say that most people can be trusted] or that you can’t be too careful in dealing with people ? ’ Endorsement of each of these items was associated with greater wealth inequalities (the size of the gap between the rich and the poor) across the states and with higher mortality rates. Strikingly, a 10 % increase in the level of trust across the states was associated with an 8 % reduction in overall mortality. A path * Address for correspondence : D. Freeman, Ph.D., King’s College London, Department of Psychology, PO Box 077, Institute of Psychiatry, Denmark Hill, London SE5 8AF, UK. (Email : Daniel.Freeman@kcl.ac.uk) Psychological Medicine (2011), 41, 923–936. f Cambridge University Press 2010 doi:10.1017/S0033291710001546 ORIGINAL ARTICLE