Background/Objectives: This cross-sectional study aimed to produce an adapted Croatian version of the Negative Behaviors in Health Care Questionnaire and to validate it. Methods: The process comprised the translation, cultural adaptation, and psychometric evaluation of the questionnaire. Clinical specialists and qualified bilingual speakers participated in both forward and backward translation. Face validity was tested. The survey’s original developer approved the final version. The reliability of the questionnaire was assessed using the test–retest method and Cronbach’s alpha coefficient. Exploratory and confirmatory factor analyses and assessments of divergent and convergent validity were conducted. The collected data were analyzed using SPSS 21.0 and R, program version 3.5.2., for Windows. Results: A five-factor structure was obtained and confirmed via CFA, although not all fit coefficients were satisfactory. The internal consistency reliability was 0.86 for the contributing factors and the seriousness of aggression, 0.79 for the use of aggression, 0.95 for the fear of retaliation, and 0.83 for the frequency of aggression; in total, α = 0.88. Test–retest reliability was moderate. All correlations were statistically significant, and the correlation was the highest for seriousness (0.754) and frequency of aggression (0.725) and the lowest for contributing factors (0.528). Test–retest reliability was satisfactory. Statistically significant differences were found when comparing respondents by gender, age, work experience, education, and hierarchical position. Conclusions: The adapted, translated, and validated survey provides a valuable tool for assessing lateral and vertical aggression between and towards nurses in terms of contributing factors, frequency, severity, uses of aggression, and fear of retaliation.

Introduction: The analgesic placebo effect refers to the phenomenon that a certain treatment that should not lead to a reduction of pain (e.g. consumption of a pill that does not contain medicinal substances with a pharmacological effect) leads to a reduction in the sensation of pain thanks primarily to specific expectations about this effect. Explanations of how and why the placebo reaction occurs in the experience of pain can be found within the framework of various theoretical models. From the very beginnings of research on the analgesic placebo effect, there has been and is still a debate whether the placebo effect is based largely on conscious expectations (Price and Barell, 2000) or different learning mechanisms, primarily through classical conditioning (Meissner et al., 2011). However, the theoretical framework that is most accepted today is the integrative model proposed by Colloca and Miller (2011). They proposed a unique model in which the placebo effect is the result of the creation of expectations that are triggered by a psychosocial context (e.g. verbal, contextual or social), including among others conditioned stimuli (learning through classical conditioning). Conscious or unconscious expectations are conditioned on the one hand by instructions about the effectiveness of a substance or procedure, by one's own experience of exposure to a certain effective treatment for pain, or by social learning (observation of other people whose pain is reduced due to the influence of a certain substance or treatment), and on the other hand are determined by contextual stimuli, prior beliefs and previous experiences. It is believed that expectations play a key role in achieving the placebo effect. It was shown that participants who were presented with painful stimuli of equal intensity in two situations, with the only difference in the induced expectations by a verbal instruction about the intensity of the stimulus, gave lower pain estimates when they expected the stimulus to be of lower intensity and less painful, compared to the situation when they had expectations that the stimulus will be very painful (Koyama et al., 2005; Colloca et al., 2008). That the expectation of positive outcomes of the therapy is the core of the placebo effect is shown by experimental studies that have shown that only the manipulation of expectations, without applying any treatment, is effective in reducing the experience of pain (Price et al., 1980; Wang et al., 2011; Ružić et al., 2017; Ritter et al., 2019). In experimental studies of the analgesic placebo effect, expectations are most often manipulated by verbal instruction given to the participants, which states what effect the applied treatment will have and what kind of sensation it should lead to. Research clearly shows that, among other things, conditioning is important for the occurrence of the placebo effect, i.e. the temporal and spatial pairing of a neutral stimulus (placebo) and an active drug or treatment. This implicitly (but also explicitly) teaches the connection between the presence of a substance (treatment) and the outcome in behavior or experience. In this linking process, a neutral stimulus (placebo substance or procedure) becomes conditioned and can cause the same reaction as an unconditioned stimulus (one that would normally lead to a reaction by itself), which is most often a certain drug or therapeutic procedure. A typical paradigm used in experimental studies of the analgesic placebo effect using conditioning consists of causing pain to the participants and giving them an analgesic (e.g. via infusion). Its use changes the experience of pain, the pain threshold or tolerance becomes higher due to the effect of the drug. In the next step, usually the next day - with the same prior stimulation, the subjects are given a placebo substrate. If after the application of a placebo, which the participants think is the medicine they received in an earlier session, there is a reduction in pain, it can be said that a placebo effect has occurred (Ivanec, 2015). Current knowledge shows that the placebo effect is not a universal phenomenon, i.e. that there are large inter-individual and intra-individual differences. Estimates are that in some clinical or experimental research, an average of 30-40 % of patients or participants show a placebo reaction (Noon, 1999). In order for the placebo effect to be considered a real phenomenon, it was first necessary to investigate its biological and neurophysiological basis. Advances in technology, particularly the development of brain imaging techniques, have provided insight into the biological mechanisms involved in the placebo effect. According to the assumed model of the formation of the analgesic placebo effect, cognitive psychological processes such as expectations interact with structures that normally participate in the processing of nerve impulses from pain receptors (ACC, S1, insula, S2, thalamus, PAG area). The assumption is that their activation results in the release of various chemical substances, from natural endogenous opiates, but also other non-opiate endogenous substances (e.g. cannabinoid substances). The consequence of this is the modulation of the painful experience, which occurs due to the inhibition of nociceptive activation, either at the level of the spinal cord or in the brain. Such a hypothesized model is called the top-down pain modulation system (Colloca et al., 2013). Although the findings of neurophysiological basis indicate that the placebo effect is a real phenomenon, there are meta-analyses that question the strength and universality of this phenomenon. Hrobjartsson and Gotzsche (2001) showed that the placebo effect appeared only in studies that used continuous measures versus dichotomous data and only in cases where subjective measures were used. These shortcomings in the research of the analgesic placebo effect were observed relatively quickly, and there is a...

This cross-sectional study aimed to produce an adapted Croatian version and validate the Negative Behaviors in Health Care Questionnaire. Methods: The translation, cultural adaptation, and psychometric evaluation of the questionnaire were approached. Clinical specialists and qualified bilingual speakers participated in both forward and backward translation. Face validity was tested. The survey's original developer approved the final version. The reliability of the questionnaire was assessed using the test-retest method and Cronbach alpha coefficient. Exploratory and confirmatory factor analyses and assessments of divergent and convergent validity were conducted for the questionnaire. The collected data were analyzed using SPSS 21.0 and R program version 3.5.2. for Windows. Results: A 5-factor structure was obtained, just like the original version of the questionnaire, which was confirmed by CFA – although not all fit coefficients were satisfactory. Internal consistency reliability was found to be high and test-retest reliability was satisfactory. Conclusions: The adapted, translated, and validated survey provides a valuable tool for assessing lateral and vertical aggression between and towards nurses regarding contributing factors, frequency, severity, uses of aggression, and fear of retaliation.