This randomized controlled trial aims to evaluate the effectiveness of participation in five different STIME (Strengthened Cross-Sectoral Initiative for Children and Young People's Mental Health) interventions: 'Signs of Disordered Eating', 'Signs of Internalizing', 'Signs of Self-Harm', 'Take the Control Back', and 'The Parent Pilots'. The hypothesis is that participation in one of these interventions will be more effective than Management As Usual (MAU). Each intervention consists of three core components: early identification and screening, therapy based on evidence-informed manuals, and support within the child's learning environment.

This project consists of five separate randomized controlled trials, each designed to evaluate the effectiveness of one of the five STIME interventions.

Mental health difficulties in childhood can have wide-ranging negative consequences for a child's development, learning, education, physical and psychological health in adulthood, family formation, and later attachment to the labor market. Thus, mental health difficulties among children and adolescents constitute a significant public health issue that requires immediate cross-sectoral action.

Existing research points to effective strategies for the prevention of progression of mental health difficulties to mental health problems that require psychiatric treatment. However, we still know relatively little about whether and how interventions work in the real-life contexts in which they are intended to function. In particular, there is a lack of research on implementation in practice-an evidence gap that may be bridged by integrating systematic evaluation components into existing prevention programs such as STIME.

STIME is a collaboration between municipalities and the regional child and adolescent psychiatry, aiming to prevent the progression of mental health difficulties among children and adolescents aged 3-17 years, before specialized treatment is required. The interventions target a subclinical population-that is, children and adolescents who show signs of mental health difficulties, such as anxiety, disordered eating, or self-harm, but who do not meet the diagnostic criterias for a mental disorder. As part of the collaboration, regional mental health services are responsible for training municipal psychologists, while the municipalities are in charge of delivering the interventions.

Although a pilot evaluation indicates that the STIME interventions are promising, there is a need for a rigorous examination of their effectiveness. The present study will therefore investigate the effectiveness of five STIME interventions.

The study will be conducted as five separate randomized controlled trials. Participants eligible for partaking in 'Signs of Disordered Eating' will be allocated either to the intervention or MAU, involving a maximum of four online 45 min sessions over a period of ten weeks with a psychologist, upon which the 'Signs of Disordered Eating' intervention will be offered. Participants eligible for participation in 'Signs of Self-harm', 'Signs of Internalizing' or 'Take the Control Back' will be allocated either to the intervention or MAU, involving a maximum of three online 45 min sessions over a period of ten weeks with a psychologist, upon which the relevant intervention will be offered. The control group psychologists will have previous experience with the appropriate populations, but no prior knowledge or training in the STIME concepts.

For 'the Parent Pilots' intervention, parents will be randomized to either commencement of the intervention within the first group or the following group, which will commence when the first group finishes after ten weeks. As such, this will be a passive waitlist control group.

The primary aim is to determine whether participation in a STIME intervention results in greater improvements in mental health difficulties and everyday functioning compared to the control group. Effectiveness will be assessed using validated measures of wellbeing (primary outcome of interest) and functionality indicators relevant to each intervention's mental health difficulty (secondary outcome of interest). Outcomes will be measured at baseline (T0), immediately post intervention (T1), and six months post baseline (T2).

Each of the interventions has elaborate and narrowly defined inclusion and exclusion criteria. These are listed below for each intervention.

'Signs of Internalizing'

Inclusion criteria

• Adolescents aged 12-17 years
• Mild to moderate impairment in daily functioning (e.g., reduced engagement in school, social life, or leisure activities compared to before symptoms)
• Adolescents with well-managed ADHD or autism may be included if they demonstrate sufficient mentalizing abilities and can benefit from the intervention with parental support
• Presence of both anxiety and depressive symptoms, neither of which dominates or meets full diagnostic criteria
• The family is motivated to participate

Exclusion criteria

• Symptoms of moderate to severe depression
• Presence of OCD, PTSD, agoraphobia, panic disorder, or other psychiatric conditions
• Low cognitive functioning
• Moderate to severe functional impairment (e.g., school dropout, extreme social withdrawal, daily reliance on adult support, lack of motivation for treatment)
• Recent unsuccessful psychological treatment
• Primary problems related to family dynamics or a highly burdened family situation
• Increased or acute suicide risk
• Presence of self-harm or symptoms of disordered eating

'Signs of Disordered Eating'

Inclusion criteria

• Children and adolescents aged 10-17 years
• High body dissatisfaction, preoccupation with food and/or body image, and/or early behavioral signs of an eating disorder
• Stable physical condition, manageable in consultation with the adolescent's general practitioner
• Able to consume food with guidance and support
• The family is motivated to participate

Exclusion criteria

• Previous treatment for an eating disorder
• Symptoms meeting criteria for specialized psychiatric treatment
• Low cognitive functioning
• Significant weight loss
• Solely restrictive or selective eating without other eating disorder symptoms
• Severe comorbidity
• Increased or acute suicide risk
• Eating difficulties solely related to lifestyle factors

'Signs of Self-Harm'

Inclusion criteria

• Adolescents aged 12-17 years
• Current thoughts of self-harm
• At least one episode of direct (non-suicidal) self-harm within the past three months
• The family is motivated to participate

Exclusion criteria

• Increased suicide risk
• Psychiatric disorder requiring further assessment or not adequately treated
• Low cognitive functioning
• Self-harm only in socially accepted contexts (e.g., piercings or tattoos)
• Only indirect self-harm (e.g., excessive substance use)
• Only self-harm by proxy (involving another person)

'Take the Control Back'

Inclusion criteria

• Children and adolescents aged 5-17 years
• Experiencing obsessive thoughts and/or compulsive behaviors of mild to moderate severity
• Experiencing self-perceived distress related to obsessive thoughts and/or compulsive behaviors
• Experiencing obsessive thoughts as egodystonic, and thus aware that they are excessive (for the youngest participants, this criterion may be waived in cases of limited insight)
• Functioning is impaired by obsessive thoughts and/or behaviors, e.g., reduced school functioning, social difficulties, or impaired functioning at home
• The family is motivated to participate

Exclusion criteria

• Symptoms meeting criteria for specialized psychiatric treatment
• Has another psychiatric disorder that requires assessment or is not adequately managed
• Has difficulties other than obsessive thoughts and behaviors that currently constitute the primary burden, and which must be addressed first
• Has previously received OCD treatment within psychiatric care (may be offered STIME if assessed but not treated due to mild severity)
• Has an increased or acute risk of suicide
• Has low functioning for other reasons, e.g., significantly reduced cognitive functioning

'the Parent Pilots'

Inclusion criteria

• Parents of children aged 3-10 years who experience developmentally inappropriate difficulties with restlessness, hyperactivity, attention, and/or impulsivity
• The symptoms must be present at home as a minimum, but may also occur across settings such as home, daycare, and school
• The child's difficulties must be significant enough to affect overall daily functioning
• The parents are motivated to participate

Exclusion Criteria:

• Symptoms of attention difficulties that require psychiatric treatment
• Presence of another psychiatric disorder that requires treatment
• Previous treatment for ADHD within the psychiatric system
• Low level of functioning due to other causes, such as significantly reduced cognitive functioning