Abstract
BACKGROUND: The assessment of adolescents' mental health competencies requires validated instruments. Thus, we sought to develop and evaluate the psychometric properties of a scale in which adolescents self-assess their competencies to act in mental health. METHODS: A psychometric study was conducted. The data was collected in Portugal between May 2022 and September 2023. Firstly, a focus group was held with 9 experts to generate the scale items. The data was examined using content analysis. Secondly, a modified e-Delphi technique was used to obtain the opinion of 97 healthcare workers on the scale statements and the classification method. An analysis of response frequencies was carried out. Thirdly, cognitive interviews about the scale were conducted with 8 adolescents. Content analysis was performed. Finally, the scale was applied to 514 adolescents. Item sensitivity assessment and factor analysis were performed. The scale's convergent and divergent validity, internal consistency and test-retest reliability were also examined. RESULTS: A 20-item scale emerged, featuring four factors: perception of knowledge about mental health, mental health self-care, interpersonal relationships and mental health first aid. Cronbach's alpha and McDonald's omega varied from 0.79 to 0.92, the composite reliability from 0.70 to 0.89, and the intraclass correlation coefficient from 0.77 to 0.80. CONCLUSIONS: The scale was created and demonstrated good validity and reliability. It facilitates the assessment of adolescents' mental health needs and the results of educational interventions.