The goal of this clinical trial is to learn if Sensory motor arousal regulation treatment (SMART) works better than treatment as usual (TAU) to treat youth 7-17 years with complex trauma histories and self-regulation difficulties. The study also will investigate which patients will benefit more from SMART (treatment effect heterogeneity) and whether therapeutic alliance mediates effect. The main hypotheses the trial aims to answer are:

1. Main effects: The SMART model approach will be more effective than ordinary treatment (control condition), in terms of improvement from therapy starts to 6 and 12 months follow up, for:

   1. Regulatory capacities of emotions and bodily states, attention and behavior, and self and social relations
   2. Trauma symptoms of re-experiencing, avoidance/ numbness and hyperarousal and sense of threat (core PTSD symptoms) and disturbances in self-organization (affect, self-concept; relations - core complex PTSD symptoms)
   3. Internalizing symptoms (somatic complaints, anxiety symptoms and depression symptom severity) and Externalizing symptoms (conduct problems, aggression, inattention, and social problem severity)
   4. Psychosocial strengths - prosocial behavior, subjective well-being and impairment in peer relationships, family relationships, and academic/school functioning

2. Exploration of mediation: When comparing SMART and ordinary treatment (TAU), (i) therapeutic alliance is higher in SMART, and (ii) a better treatment effect in SMART is partially mediated by therapeutic alliance

3. Exploration of treatment effect heterogeneity (moderators): Effects of SMART treatment compared to TAU vary between: patients with low versus high level of self-regulation difficulties (full vs partial Developmental trauma disorder), patients with extensive vs less extensive developmental trauma exposure, adolescents (13-17 years) vs younger children (7-12 years), and patients exposed to trauma early in life vs in their teens

At each site, eligible participants are randomized to SMART or ordinary treatment/ TAU. Investigators acquire study data at baseline and outcome data at follow up after 6 and 12 months, and measure therapeutic alliance twice during the treatment process.

Specialized mental health services often fall short in adequate treatment of youth with developmental trauma histories. These youth are often difficult to treat due to composite mental and somatic problems. A promising treatment model for the group is the SMART approach, which utilizes sensory motor therapeutic equipment in a specialized room to support youths' natural ways of regulating bodies and emotions. This may facilitate therapeutic bond, improve regulation of arousal, and facilitate a more effective processing of trauma. The study will test the effectiveness of SMART treatment for young people 7-17 years old with developmental trauma and self-regulation difficulties in a two-group RCT. The investigators hypothesize that the SMART approach is more effective than ordinary treatment for an array of outcome measures, including regulatory capacities, attention and behavior; trauma symptoms; and internalizing and externalizing symptoms. The study also will explore if therapeutic alliance mediates treatment effects and heterogeneity of treatment effects (moderator analyses). The study will include 120 children/ adolescents with developmental trauma exposure and difficulties in self-regulatory capacities from four units at dpt. of child and adolescent mental health, Vestre Viken, randomized to SMART or ordinary treatment. This first RCT of SMART for youth has the potential to test whether the model should be adopted as standard treatment for youth in the target group in Norway and internationally.

Inclusion criteria:

These are based on the Developmental Trauma Disorder Semistructured Interview (DTD-SI), which has four domains (A-D). Based on the DTD-SI, which is detailed below, inclusion requires:

• The presence of developmental trauma history (domain A)
• One symptom in each of the domains B-D
• At least four symptoms (of a maximum 15) in domains B-D considered together

Domains A to D above refers to the following:

• Domain A. Lifetime contemporaneous exposure to developmental trauma, defined as either (i) Interpersonal victimization: physical or sexual abuse or assault, domestic/intimate partner violence, bullying, harassment, exploitation, trafficking, hate crimes, or racial/ethnic/identity trauma, or (ii) Primary caregiving system attachment disruption: caregiver change or prolonged separation, gross neglect (physical, medical, emotional), psychological maltreatment (emotional abuse, emotional neglect, parental hostility or over-controlling), caregiver impairment due to mental illness or substance abuse, or chronic medical condition (by child or caregiver)
• Domain B. Affective and somatic dysregulation: (i) Emotion dysregulation, (ii) Somatic dysregulation, (iii) Impaired awareness or dissociation of emotions and body, (iv) Impaired capacity to describe emotions or bodily states
• Domain C. Attentional and behavioral dysregulation: (i) Threat-related rumination, (ii) Impaired capacity for self protection, (iii) Maladaptive self-soothing, (iv) Habitual or reactive self-harm, (v) Inability to initiate or sustain goal-directed behavior
• Domain D. Self and relational dysregulation: (i) Persistent extreme negative self-perception, (ii) attachment insecurity and disorganization, (iii) Extreme persistent distrust, defiance or lack of reciprocity in close relationships, (iv) Reactive physical or verbal aggression, (v) Psychological boundary deficits, (vi) Impaired capacity to regulate empathic arousal

Exclusion Criteria:

• Active psychosis
• Not fluent in Norwegian language
• Developmental challenges - IQ < 70
• Has previously used SMART room