A blinded validation of the Swedish version of the Clinical Assessment Interview for Negative Symptoms (CAINS)

Abstract

Purpose

The Clinical Assessment Interview for Negative Symptoms (CAINS) was developed in order to advance the assessment of negative symptoms. The aim of this study was to validate the Swedish version of the CAINS.

Materials and methods

Thirty-four out-patients with a schizophrenia spectrum disorder were recruited. All patients were videotaped while interviewed with the CAINS and the Brief Psychiatric Rating Scale (BPRS). Another rater watched the video recordings in the reverse order, enabling a blinded design. The patients also filled in self-reported measures of depression, quality of life, and social and vocational functioning. We calculated inter-rater agreement and internal consistency for the CAINS. We also calculated validity measures by correlating the subscales Motivation and Pleasure (CAINS-MAP) and Expression (CAINS-EXP) to subscales of the BPRS.

Results

The blinded inter-rater agreement for the CAINS total score was high (ICC = 0.92) but slightly lower for the expression subscale (ICC = 0.76). Cronbach’s alpha was 0.84 for the total score. Convergent validity with the negative symptoms subscale of BPRS was different for the blinded and the unblinded data, with a CAINS-MAP correlation of 0.10 (p = 0.580) and a CAINS-EXP correlation of 0.48 (p = 0.004) in the blinded data. The unblinded data had a CAINS-MAP correlation of 0.38 (p = 0.026) and a CAINS-EXP correlation of 0.87 (p < 0.001). Self-rated measures of anhedonia correlated to CAINS-MAP with a coefficient of 0.68 (p < 0.001), while the CAINS-EXP only had a correlation of 0.16 (p = 0.366) to these measures.

Conclusion

The Swedish version of the CAINS displays adequate psychometric properties in line with earlier validation studies.

Keywords:

• Psychometric
• motivation
• pleasure
• expression
• schizophrenia

Acknowledgements

We wish to thank all the patients participating in the study and all the staff at the psychosis clinic for their help in recruiting the patients. We also wish to thank the personnel at the research clinic and Linda Steinholtz and Elin Thörnblom for valuable discussions during the training process. Lastly, we thank professor Lisa Ekselius for comments during the design of the study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes on contributors

Johan Bengtsson is a resident in psychiatry and PhD-student.

Robert Bodén, PhD, is a senior consultant in psychiatry at the Brain Stimulation Unit and associate professor in psychiatry.

Daniel Neider is a senior consultant in psychiatry.

Martin Cernvall, PhD, is a clinical psychologist at the psychosis outpatient unit. All at Uppsala University Hospital and the department of neuroscience, Uppsala University.

Additional information

Funding

The

work was supported by the Märta and Nicke Nasvell Foundation, Selander Foundation, Söderström-Königska Foundation and Linné Foundation. RB was supported by the Swedish Research Council under [Grant 2016-02362], and the Gullstrand Research Fellow grant from Uppsala County Council. JB was granted conference attendance from Anna Maria Lundin’s scholarship committee.