Our interest in resilience arose from long experience treating men and women with posttraumatic stress disorder (PTSD), as well as from our broad-range research into the disorder, which covered treatment assessment, diagnosis, biological characterization, cross-cultural study, epidemiology, risk factors and the development of measures for PTSD and other forms of anxiety.

Among the measures which we felt needed a stronger presence in the field of PTSD assessment was that of resilience. Although several scales addressing aspects of resilience have existed for some time, they had largely failed to penetrate into the world of clinical practice. In our treatment studies of PTSD we noticed that besides reducing the symptoms of the disorder, subjects became better able to handle stress and seemed to become more resilient.

After a search of the resilience literature, which for a long time was heavily influenced by contributions from the specialties of developmental psychology and child psychiatry, we selected 17 domains, as outlined in Table 1 of our publication in 2003, and developed a 25 item scale (Connor KM, Davidson JRT. Depression and Anxiety 2003; 18: 71-82). This report presented psychometric data establishing validity and reliability of the scale (known as the Connor-Davidson Resilience Scale or CD-RISC), as well as briefly describing each of the 25 items (see table 2 of that citation), and giving general scoring directions. However, the complete wording for each item and full directions did not appear in the report and the scale cannot be adequately reconstructed from the information given in this publication.

In the original validation study, mean scores in specific populations were reported as follows:

US general population 80.7
Primary care patients 71.8
Psychiatric outpatients 68.0
Generalized anxiety 62.4
2 PTSD samples 47.8 & 52.8

Besides the full 25-item CD-RISC (or CD-RISC 25), there are two briefer versions, the 10 item (CD-RISC 10) and two item (CD-RISC 2) scales. The 10 item version (score range 0-40) comprises items 1, 4, 6, 7, 8, 11, 14, 16, 17, 19 from the original scale, and was developed by Drs. Campbell-Sills and Stein, at the University of California, San Diego, on the basis of factor analysis. In a community survey of 764 US adults, a mean score of 31.8 (SD = 5.4) was obtained for the CD-RISC 10 (Campbell-Sills L, Forde DR, Stein MB. J Psychiatric Research (2009), doi:10.1016/j.jpsychires.2009.01.013). An almost identical mean score was obtained by Davidson in the US general population sample studied in the 2003 report above.

The CD-RISC 2 is based on items 1 and 8 (score range from 0-8), and was developed as a measure of "bounce-back" and adaptability by the original authors (Vaishnavi et al, 2007). In a general population survey of US adults, mean CD-RISC 2 score was 6.91, while lower scores were observed in psychiatric groups with depression (5.12), GAD (4.96) and PTSD (4.70) (Vaishnavi et al, 2007) and in survivors of the Southeast Asian Tsunami of 2004 (Irmansyah et al, 2010).

The CD-RISC literature continues to grow: the scale has now been translated into many different languages and studied in a variety of populations, including large community samples, survivors of various traumas, Alzheimer's caregivers, adolescents, elders, patients in treatment for PTSD, members of different ethnic groups and cultures, and selected professional or athletic groups (e.g. university students, nurses, social workers, physicians, military medical personnel, medical students, missionaries, cricketers). The CD-RISC has been included in functional neuroimaging studies, studies which utilized genotyping and studies which assessed treatment outcome. Psychometric properties of the RISC hold up in nearly all studies, although its factor structure and mean score varies with setting. For this reason, we do not recommend separate scoring of the factor subscales which were originally reported by Connor and Davidson, even though some interesting findings have been reported when specific factors or items were selected (e.g. Laff, 2008; Garcia-Izquierdo et al, 2009).