A Mentalization Based Prevention Program to Foster Well-Being and Mental Health in Pre-Adolescent Children and Their Families

Children's well-being measured by the KIDSCREEN-10 (Ravens-Sieberer et al., 2010)

To assess children's well-being, the KIDSCREEN10 Index will be used both as a self-report completed by the children and as an external proxy report provided by their parents. Responses are recorded on a 5-point Likert scale ranging from 1 (not at all/never) to 5 (very much/always). The ten items on mental health are summed up to yield a total score ranging from 10 to 50, where lower scores indicate poorer mental health and higher scores reflect better mental health.

Children's mental health measured by the SDQ (Goodman, 1997)

The Strengths and Difficulties Questionnaire (SDQ) will be used to assess mental health difficulties in children. The SDQ is completed as an external proxy report by parents and consists of 25 items, which are distributed across five subscales: Emotional Symptoms, Conduct Problems, Hyperactivity/Inattention, Peer Relationship Problems, and Prosocial Behavior. Items are rated on a 3-point Likert scale ranging from 0 (not true) to 2 (certainly true). For each subscale, items scores are summed to yield a total score. Additionally, a Total Difficulties Score is calculated by summing the scores of the first four subscales, whereas the Prosocial Behavior subscale is analyzed separately. Higher scores on the Total Difficulties Scale indicate increased behavioral and emotional challenges, whereas higher scores on the Prosocial Behavior subscale reflect stronger social competencies.

Parental well-being measured by the EQ-5D-5L (EuroQol Group, 1990; Herdman et al., 2011)

Well-being of parents will be measured using the European Quality of Life 5 Dimensions 5 Level Version. Parents assess their level of well-being across five dimensions: Mobility, Self-care, Usual activities, Pain/Discomfort, and Anxiety/Depression. Response options include: no, slightg, moderate, severe, extreme problems. Additionally, participants complete a scale on which they can rate their current health from 0-100, with 100 being the best possible health and 0 the worst possible health. Scores for the five-dimensional scale will be summed and treated separately to the health-scale score.

Parental mental health measured by the DASS-21 (Lovibond & Lovibond, 1995)

The Depression, Anxiety and Stress Scale-Short Version will be used to assess mental health in parents over the past seven days based on severity. The 21 items are divided into three 7-item subscales, each representing one of the emotional states. The items are rated on a 4-point Likert-type scale ranging from 0 (Does not apply to me at all) to 3 (Applied to me very much or most of the time). The severity score for each subscale is calculated by summing the valid item scores and multiplying the result by two.

Children's Positive Mental Health measured by the PMH-Kids (Lippert et al., 2024)

The Positive Mental Health Scale for children and adolescents (PMH-Kids) measures positive mental health in children and adolescents between 6 and 18 years old. The scale consists of 9 self-reported items. The items are rated on a 4-point Likert-type scale ranging from 0 (do not agree) to 3 (totally agree). The total score ranges from 0 to 27 with higher scores representing a higher degree of positive mental health.

Children's stigma towards mental health measured by the PMHSS (McKeague et al., 2015)

The Peer Mental Health Stigmatization Scale (PMHSS) will be used to assess stigmatizing attitudes towards children with mental health. The questionnaire comprises 11 items rated on a 5-point Likert scale ranging from 1 (strongly agree) to 5 (strongly disagree).The total stigma score is calculated by summing responses across all items. The resulting scores range from 11 to 55, whereby a lower score indicates a higher level of stigmatization.

Children's Help-seeking behavior measured by the AHSQ (Rickwood & Braithwaite, 1994)

The Actual Help-Seeking Questionnaire will be used to assess actual help-seeking behavior. Children will be asked to tick resources from a provided checklist of 8 potential resources from whom they have sought help in the past six months because they experienced a mental health problem. In addition, they will have the option to add a person not listed, to indicate that they did not seek help from anyone, and to indicate that they did not have a mental health problem in the past six months.

Parental Positive Mental Health measured by the PMH (Lukat et al., 2016)

The Positive Mental Health Scale (PMH) will be used to assess positive mental health in parents. The scale consists of 9 self-reported items. The items are rated on a 4-point Likert-type scale ranging from 0 (Do not agree) to 3 (Totally agree). The total score ranges from 0 to 27 with higher scores representing a higher degree of positive mental health.

Mediator-Children's bias in mentalization measured by the Biased Mentalization Task

Bias in mentalization, i.e. an overly negative, balanced or overly positive judgment of peer-interactions, will be assessed using an adapted version of the Biased Mentalization Task (Sharp et al., 2007). The adapted version was approved by the authors of the original publication. The Biased Mentalization Task measures biases in mentalizing through the use of 10 ambiguous peer-related social scenarios. The children can choose from three response options: One response option that contains an overly positive bias, one response option that contains an overly negative bias and a balanced response option. Each scenario will be displayed as a video. Frequency analyses and latent class analyses will be used to divide the children into the three bias types.

Mediator-Children's Emotion Regulation measured by the ERQ-CA (Gullone & Taffe, 2012)

The Emotion Regulation Questionnaire for Children and Adolescents (ERQ-CA) will be used to assess the use of two emotion regulation strategies - cognitive reappraisal and expressive suppression. The scale consists of 10 items answered on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). Subscale scores are calculated as the mean of the valid items.

Mediator-Attention regulation (Smolker et al., 2022)

The Emotional Word-Emotional Face Stroop (EWEFS) task assesses attentional processes in children by measuring cognitive control over emotionally distracting stimuli and concurrently indexing processing speed and attentional vigilance via performance on congruent trials. On each trial, participants classify the emotional valence of a centrally presented word (positive or negative) via button press while ignoring a task-irrelevant face displaying either congruent or incongruent emotion. The task comprises 96 trials split into two 48-trial blocks: a mostly congruent block (75% congruent, 25% incongruent) and an equal block (50 % congruent, 50 % incongruent). Reaction time (RT) and accuracy on congruent trials capture basic processing speed and attentional vigilance.

Mediator-Parental Mentalization measured by the PRFQ-A (Luyten et al., 2017)

The Parental Reflective Functioning Questionnaire Adolescent version (PRFQ-A) will be used to assess parental reflective functioning, i.e. a parent's capacity to understand and interpret both their own and their child's mental states. The PRFQ-A consists of 18 self-report items, divided into three subscales: Pre-Mentalizing Modes (PM), Certainty about Mental States (CMS), and Interest and Curiosity (IC). Items are rated on a 7-point Likert-scale ranging from 1= "Strongly disagree" to 7=" Strongly agree". Subscale scores are calculated as the mean of the respective items of each respective subscale. Higher scores on the PM subscale indicate greater difficulties in mentalizing, whereas higher scores on the CMS and IC subscales reflect greater certainty and curiosity about the child's mental states, respectively. It should be noted that a very high score on the CMS or IC subscale may indicate hyper/pseudo-mentalizing.