Background Dementia causes behavioural changes in people that often lead to earlier placement in a nursing home. Staff can find these behavioural changes challenging and require specific competencies to support and care of people living with dementia. However, there is little information regarding the competencies nurses require in dementia care. Thus, the aims of this study were to determine the prevalence of challenging situations in nursing homes of older people with dementia, characterise the nursing staff's responses to such situations and contribute to a model outlining competences that dementia care nurses require. Methods Data were collected using mixed methods in a cross‐sectional survey of views of nursing staff (n = 106) in two nursing homes in Finland during May to June 2018 using a structured questionnaire including open‐ended questions. Quantitative data acquired were analysed statistically, and responses to the open‐ended question were analysed using content analysis methodology. Results Most nurses (98%) reported that challenging situations occurred daily or weekly. The most common reported forms of challenging behaviour were as follows: wandering, restlessness, constant leaving, repeated inquiries and requests and opposition to treatment (mentioned by 95%, 90%, 85%, 83% and 83% of respondents, respectively). Five key competencies were identified from their responses: practical knowledge, theoretical knowledge, therapeutic use of self, social competence and self‐management. They also indicated significant correlations between leadership and both the impact of challenging behaviour on coping at work and use of physical restraints on older people with dementia. Conclusion Challenging situations in nursing homes of older people with dementia are very common. There is a need to identify specific competencies for caring for people with dementia in addition to updating official guidelines to handle such situations. The support of supervisors and competencies related to therapeutic use of self in nursing are highly important for nurses providing care for people with dementia.

Various dementia training interventions have been developed for nursing staff, but there is inconclusive evidence on their effectiveness and which elements are key to positive outcomes. The aim of this study was to evaluate how nurses assess the prevalence of challenging behavior of people with dementia, nursing staff members’ responses to challenging behavior, and nurses’ competence, before the training and three and 12 months after the training. The main content of the training intervention was advancing person-centered care and its development. Data were collected through a survey of nursing staff ( n = 127) at two Finnish nursing homes across three distinct time points. The TREND statement was used to enhance the quality and transparency of the research. The prevalence of challenging behavior in the experimental group significantly decreased one year after training, while no change was observed in the control group. No change in nursing staff members’ responses to challenging behavior was observed in either group over the study period. Nurses in the experimental group demonstrated significant improvements in self-assessed competence both three months and one year after the training intervention. Hence, regular nursing staff training can decrease the prevalence of challenging behavior among older people with dementia and enhance nurses’ competence in nursing. The support of supervisors plays a significant role in these changes.