Development and validation of the Test of Mental Health Literacy for Supporting Children

: This study aimed to develop the Test of Mental Health Literacy for Supporting Children (T-MHLSC), a novel criterion-referenced tool assessing adults’ knowledge and beliefs about the mental health of children aged 5–12, and to examine its psychometric properties. initial validation with child mental health clinicians (n = 42), cognitive testing with potential users (2 parents, 3educators, and 7 health professionals), and a quantitative pilot with parents (n = 1176). In Phase 4, construct validity and test–retest reliability were evaluated in a diverse sample of adults living or working with children aged 5–12, including parents/carers (n = 111), educators (n = 102), and general health professionals and child mental health clinicians/researchers (n = 112). : The final T-MHLSC comprises two vignettes, each followed by five measure questions, plus one questions about child mental health in general. Potential users rated the measure as clear, accessible, and non-stigmatizing, and the vignettes demonstrated strong ecological validity. The measure effectively distinguished different levels of MHLSC, showed the expected negative correlation with stigma and positive correlation with empathy toward children with mental health problems, and demonstrated moderate to good test–retest reliability. : The validated T-MHLSC is a practical, accessible, and psychometrically robust tool for assessing adults’ knowledge and beliefs about supporting child mental health.