Copyright © The British Psychological Society Reproduction in any form (including the internet) is prohibited without prior permission from the Society Brief report Responding mindfully to unpleasant thoughts and images: Reliability and validity of the Southampton mindfulness questionnaire (SMQ) Paul Chadwick 1,2 *, Martin Hember 2 , Janette Symes 2 , Emmanuelle Peters 3 , Elizabeth Kuipers 3,4 and Dave Dagnan 5 1 Department of Psychiatry, Royal South Hants Hospital, Southampton, UK 2 University of Southampton, Southampton, UK 3 Institute of Psychiatry, King’s College London, London, UK 4 NIHR Biomedical Research Centre, London, UK 5 Lancaster University, Lancaster, UK Objective. To assess the reliability and validity of the Southampton mindfulness questionnaire (SMQ), a 16-item measure of mindful awareness of distressing thoughts and images. Methods. A total of 256 people participated, comprising a non-clinical community sample of 134 (83 meditators and 51 non-meditators) and a clinical sample of 122 people with a current distressing psychosis. To assess concurrent validity, non-clinical participants and half clinical participants (total 197 participants) completed the mindful attention awareness scale (MAAS). Predicted links were assessed with affect, and 59 patients completed a validated measure to assess link between mindfulness and intensity of ‘delusional’ experience. Results. The scale has a single factor structure, was internally reliable, significantly correlated with the MAAS, showed expected associations with affect, and distinguished among meditators, non-meditators and people with psychosis. Conclusions. The data support use of the SMQ in clinical practice and research to assess mindful responding to distressing thoughts and images. The emergence of mindfulness and acceptance based therapies (e.g. Hayes, Strosahl, & Wilson, 1999; Kabat-Zinn, 1990; Linehan, 1993; Segal, Teasdale, & Williams, 2002) has changed clinical psychology research and practice. Measures of the multiple facets of mindfulness are needed to elucidate mechanisms of change in such therapies * Correspondence should be addressed to Professor Paul Chadwick, Department of Psychiatry, Royal South Hants Hospital, Southampton SO14 OYG, UK, (e-mail: paul.chadwick@hantspt-sw.nhs.uk). The British Psychological Society 451 British Journal of Clinical Psychology (2008), 47, 451–455 q 2008 The British Psychological Society www.bpsjournals.co.uk DOI:10.1348/014466508X314891