Supplementary Material for: The WHO-5 Well-Being Index: A Systematic Review of the Literature

<b><i>Background:</i></b> The 5-item World Health Organization Well-Being Index (WHO-5) is among the most widely used questionnaires assessing subjective psychological well-being. Since its first publication in 1998, the WHO-5 has been translated into more than 30 languages and has been used in research studies all over the world. We now provide a systematic review of the literature on the WHO-5. <b><i>Methods:</i></b> We conducted a systematic search for literature on the WHO-5 in PubMed and PsycINFO in accordance with the PRISMA guidelines. In our review of the identified articles, we focused particularly on the following aspects: (1) the clinimetric validity of the WHO-5; (2) the responsiveness/sensitivity of the WHO-5 in controlled clinical trials; (3) the potential of the WHO-5 as a screening tool for depression, and (4) the applicability of the WHO-5 across study fields. <b><i>Results:</i></b> A total of 213 articles met the predefined criteria for inclusion in the review. The review demonstrated that the WHO-5 has high clinimetric validity, can be used as an outcome measure balancing the wanted and unwanted effects of treatments, is a sensitive and specific screening tool for depression and its applicability across study fields is very high. <b><i>Conclusions:</i></b> The WHO-5 is a short questionnaire consisting of 5 simple and non-invasive questions, which tap into the subjective well-being of the respondents. The scale has adequate validity both as a screening tool for depression and as an outcome measure in clinical trials and has been applied successfully across a wide range of study fields.