Validity and reliability of the questionnaire

The EBQ comprised of five items about nurses’ feelings while working with patients with NSSI. The reliability of this section was modest (α = 0.772).

For the SHAS, the original authors used 23 (out of a possible 29) attitudinal items, which they combined into 6 factors: 1) Competence Appraisal, 2) Care Futility, 3) Client Intent Manipulation, 4) Acceptance and Understanding, 5) Rights and Responsibilities and 6) Needs Function. The internal consistency of the original scale was α = 0.89, although the individual sections ranged from 0.52–0.81 [34]. The reliability of the entire scale for the present study was lower (α = 0.58). We improved the reliability of our scale (to α = 0.61) by excluding three statements: Question Nr. 30: “I am highly supportive towards clients who self-harm “, Question Nr. 8: “An individual has the right to self-harm” and Question Nr. 17: “For some individuals self-harm can be a way of relieving tension”, a method allowed by the statistical program (SPSS version 20.0, SPSS Inc., Chicago, IL, USA). Hereinafter these three statements were no longer used in the analyses. The acquired data were not suitable for factor analysis according to the required conditions due to the small sample size [35], therefore we analyzed and interpreted each statement separately and didn’t use reverse scoring or calculate the cumulative scale.