Background:  Children and adolescents with mental health problems are widely reported to have problems with peer relationships; however, few studies have explored the way in which these children are regarded by their peers. For example, little is known about the nature of peer stigmatisation, and no published research has investigated implicit attitudes thus ensuring that stigma is not well understood. To address this issue, the current study explored patterns of explicit and implicit stigmatisation of peers with depression and attention deficit hyperactivity disorder (ADHD). Methods:  The sample was 385 children (M = 10.21 years) and adolescents (M = 15.36 years). Participants completed a questionnaire assessing explicit stigma towards an age‐ and gender‐matched peer with ADHD or depression and another peer with ‘normal issues’ who were described in vignettes. They also completed a modified version of the Implicit Association Test (IAT) that explored implicit attitudes towards the target peers. Results:  Questionnaire data indicated that the peer with ADHD was perceived more negatively than the peer with depression on all dimensions of stigma, except perceived dangerousness and fear. In contrast, the IAT findings suggest that some participants had more negative views of the peer with depression than the peer with ADHD. Specifically, the findings demonstrate that adolescent males demonstrated significantly stronger negative implicit evaluations of depression compared with younger males and adolescent females. Conclusions:  Children and adolescents demonstrate stigmatising responses to peers with common mental health problems. The nature and extent of these responses depends on the type of problem and the type of measurement used. The findings highlight the importance of using both explicit and implicit measures of stigma.

Background: The nature of stigmatizing attitudes towards children and adolescents with mental health problems has received little empirical attention, despite consensus that such attitudes are widespread. As a consequence, much less is known about stigma in childhood and adolescence and methods of stigma measurement are frequently borrowed from the adult literature. For research on this topic to develop, a theoretically based and developmentally appropriate measure is needed. This study aimed to develop a theory-based peer stigma questionnaire suitable for children and adolescents. Method: Participants were 562 children and adolescents aged 9-16 years (M = 12.99 years; SD = 1.6 years) in the Republic of Ireland, 316 female, all were White. The Peer Mental Health Stigmatization Scale (PMHSS) contains 24 statements (negative and positive) about peers with mental health problems that are rated on a 5-point scale. Participants also completed the Strengths and Difficulties Questionnaire. Re-test data was collected after 2 weeks from 109 participants. Results: Principal Components Analysis on the negative statements indicate the presence of two components: Stigma Agreement, personal endorsement of stigmatising statements and Stigma Awareness: awareness of prevailing societal stigma towards youth with mental health problems. The positive statements include three components: Intellectual Ability, Recovery and Friendship. Conclusions: The PMHSS is a psychometrically sound instrument with good retest reliability suitable for use with older children and teenagers. Initial use of the scale suggests that personal endorsement of stigma is lower than perceptions of public stigma. Key Practitioner Message• The measurement of mental health stigma in children and adolescents has received little attention and most studies have used adapted questionnaires developed for adults without presenting evidence on their appropriateness or psychometric properties.• The stigma construct used to develop the Peer Mental Health Stigmatization Scale (PMHSS) comprises stereotypes, prejudice, discrimination and lower status.• The PMHSS can be administered to children as young as 9 years and yields a total stigma score, a total score for endorsement of positive statements as well as scores on separate subscales.• The findings demonstrate that children and adolescents distinguish between societal stigma (what most people think) and personal stigma (what I think) in relation to mental health problems.

During childhood and adolescence, self-stigma is characterized by a sense of being different from peers and negative self-evaluation as a consequence of that difference. However, our findings also demonstrated that some young people were prepared to challenge the stigma they experienced. Further research is needed to understand the factors that contribute to these differing responses and to develop antistigma interventions that facilitate the inclusion of young people with mental health problems in their peer groups.

Young people with mental health problems are often excluded from their peer group; however, research has not specifically explored their peers’ explanations for this exclusion. Drawing on data from group interviews with Irish adolescents (N = 148), this study explores the reasons offered for rejecting young people with mental health problems. Such reasons include perceived violation of expectations of friendships, and perceived social and personal risks to members of the peer group. The implications of these findings for the development of interventions to combat the stigma of mental health problems are discussed.

Stigma research suggests that exclusion of peers with mental health problems is acceptable, however, no research has explored young people's beliefs about the fairness of exclusion. Group interviews with 148 adolescents explored judgements about the fairness of excluding peers with ADHD or depression from dyads and groups. Young people evaluated exclusion of peers with ADHD or depression from dyads and groups, with the exception of group exclusion of the peer with ADHD, as mostly unfair. Beliefs about the fairness of exclusion were influenced by the attributions that they applied to the target peer's behaviour, social obligations and loyalty within friendships and concerns about the adverse psychological effects of exclusion. Furthermore, their evaluations were influenced by personal beliefs about the social and personal costs of including the target peer. Evaluations of exclusion highlight novel avenues for to develop knowledge on the stigma of mental health problems.