The aim of this clinical trial is to test the effectiveness of the parent training intervention Supportive Parents - Coping Kids (SPARCK) for prevention of childhood mental health problems. The main research questions are:

• Is SPARCK effective in preventing and reducing negative outcomes and promoting positive outcomes for eligible children and parents compared with regular care practice?

In addition, investigators will conduct an implementation study to examine relations between implementation determinants and implementation and clinical outcomes in the SPARCK intervention condition

Participants in the effectiveness trial will be randomized to receive either the SPARCK intervention or active regular care practices provided by professionals in the Norwegian frontline services. Researchers will test the effectiveness of the SPARCK intervention at post treatment and six months follow-up.

SPARCK is a novel transdiagnostic and preventive parent intervention targeting parents with children aged 4 to 12 years with elevated, yet subclinical, symptoms of anxiety, depression (internalizing) and/or behavioral problems (externalizing). In this project, investigators will conduct a randomized effectiveness trial with families randomized to SPARCK or regular care practices in the Norwegian frontline services, e.g. child welfare services, health services, and school health services. Investigators will study potential effects of SPARCK primarily on a) child symptoms when compared with regular care, and secondary on b) parenting practices, self-efficacy and stress, c) parent and child stress regulation as indexed by stress hormones (cortisol and DHEA) in hair, d) referrals to specialized services and CWS, and e) child and parent subjective quality of life. Additionally, Investigators will study facilitators and barriers to successful implementation and the relation between implementation and clinical outcomes.

Design: Two-armed parallel group randomized controlled trial. Families will be assessed at three time points: At pre intervention, at post (intervention termination), and at follow-up six months after post assessment. In cases were intervention exceeds 24 weeks, we will assess post at week 25. In such cases, follow-up will be assessed six months after week 25. Stress hormones will be collected at pre intervention and four weeks after intervention termination.

Despite a relatively heterogeneous target group, investigators expect a balanced design in terms of symptom domains and comorbidity across internalizing and externalizing symptoms. However, there is some uncertainty regarding the frequency of children with depressive symptoms exclusively (in contrast to symptoms of anxiety or behavioral problems). Our primary outcomes reflect the transdiagnostic feature of SPARCK; targeting anxiety, depression, and externalizing symptoms. Eligible children may display symptoms symptoms in ether one, two, or across all three symptom domains. Accordingly, investigators do only expect change in a relevant symptom domain if children display elevated levels at pre intervention.

Data will be inspected the data halfway through the data collection to monitor various issues, such as the distribution of symptoms of study families at intake and potential harm to study families. For instance, if children with depressive symptoms exclusively is low-frequent at intake, investigators may modify relevant hypotheses and accompanying primary outcome. An external researcher which is not part of the project will oversee the process.

To investigate the implementation part of the project, investigators will include a quantitative data gathering amongst SPARCK practitioners and their service leaders over three time points; intervention time point 1 (iT1; at project start), iT2 (after one year of data collection), and iT3 (after two years of data collection.).

Recruitment, analysis, and power: Participant recruitment in the effectiveness study will follow regular care procedures for screening and inclusion into the frontline services. Eligible families will be randomized within each site with a 50% chance of being allocated to control or intervention group. To promote predictability for the services in terms of intervention delivery, pairwise randomization within each site will be conducted. To prevent delay of intervention, and if an eligible second case match is not recruited within a four week period, a single block randomization will be done. Blocks are nested within each municipal site and the size of the block is blinded for study personnel and the sites. Randomization will be executed by an external provider, Klinforsk (www.klinforsk.no). The effect of the SPARCK vs. regular care will be indicated through a group (between) by time (within) interaction effect in a mixed effect repeated measures design. With an expected weak effect size of f =0.1, GPOWER 3.1 estimates the necessary n to detect group by time interaction with 80% power to be 164, but this is based on no design effects and no dropout. Assuming a therapist intraclass correlation of 0.08, with 4 cases per therapist, the design effect is 1.24, giving an effective n of 80% of the nominal n. Correcting for design effects and 20 % potential dropout the needed effective sample size is 252.

Inclusion Criteria:

• Children displaying elevated symptoms of internalizing or/and externalizing problems

Exclusion Criteria:

• Child is referred to or receives ongoing help in the specialized mental health services for problems in the internalizing or externalizing domains
• Child is diagnosed with psychosis, mental retardation or pervasive developmental disorder
• Acute suicide risk
• Documented or probable ongoing physical or sexual abuse
• Child or caretakers receives other systematic interventions targeting internalizing or externalizing problems while enrolled in the study (prior to 6 month follow-up)

Participants are to be masked to what treatment condition they are assigned to, whether they receive the treatment or control condition. Treatment conditions are termed group 1 and group 2.