Brief report An investigation into the relationship between salivary cortisol, stress, anxiety and depression Kav Vedhara a,b, *, Jeremy Miles c , Paul Bennett d , Sue Plummer e , Deborah Tallon b , Emily Brooks a , Lone Gale a , Katherine Munnoch a , Christa Schreiber- Kounine f , Clare Fowler f , Stafford Lightman g , Alistair Sammon f , Zenon Rayter f , John Farndon f a Department of Experimental Psychology, Human Stress Research Unit, University of Bristol, 8 Woodland Road, Clifton, Bristol BS8 1TN, UK b MRC Health Services Research Collaboration, Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, Clifton, Bristol BS8 2PR, UK c Department of Health Sciences, University of York, York YO10 5DD, UK d Health Services Research Focus, University of Wales College of Medicine, Cardiff CF14 4XN, UK e Diagnostech, York Chambers, York Street, Swansea SA1 3NJ, UK f Department of Surgery, University of Bristol, Bristol Royal Infirmary, Bristol BS2 8HW, UK g Department of Medicine, University of Bristol, Bristol Royal Infirmary, Bristol BS2 8HW, UK Received 22 April 2002; accepted 8 September 2002 Abstract This study examined the relationship between indices of self-reported emotional distress and absolute versus change in cortisol levels. Fifty-four women attending a diagnostic breast clinic completed scales measuring stress, anxiety and depression and provided five saliva samples over the course of a single day for the measurement of cortisol. No significant relationships were evident between absolute cortisol levels and the distress measures. Analysis of the change in cortisol levels revealed a non-linear interaction effect between stress and anxiety and time of day. There was a non-linear relation between time of day and cortisol levels, but the extent of the non-linearity was dependent upon levels of stress and anxiety, not depression. A relationship was apparent between indices of distress and change in cortisol levels, but not absolute levels of the hormone. # 2002 Elsevier Science B.V. All rights reserved. * Corresponding author. Tel.:  /44-117-928-7243; fax:  /44-117-928-7236. E-mail address: k.vedhara@bristol.ac.uk (K. Vedhara). Biological Psychology 62 (2003) 89  /96 www.elsevier.com/locate/biopsycho 0301-0511/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0301-0511(02)00128-X