Revisión de modelos para la estimación de variables biofísicas 59

Studies III and IV are based on data from a randomized, controlled, pragmatic trial our research group carried out, comparing NET to TAU among children and adolescents multiply traumatized by experiences of war and refugeedom or violence in the family. The trial had an open-label, multicentre, parallel-group design, with both intervention and control treatments taking place simultaneously in usual care environments at different specialized and primary care level clinics and units across Finland.

We preregistered the trial in the ClinicalTrials.gov database (NCT02425280) before data collection commenced. We also published a detailed study protocol of the trial beforehand (Kangaslampi, Garoff, & Peltonen, 2015). Some changes to the study procedure were necessary after the publication of the protocol. In particular, 1) the inclusion criteria of the study were extended to also allow participation of children and adolescents who had been exposed to repeated interpersonal trauma within the family in the form of physical and/or sexual abuse; 2) we were unable to include the planned assessments of cognitive abilities in the study; 3) as treatment queues were shorter than expected, we were not able to collect a representative waiting-list type

control condition during time spent waiting for treatment; and 4) the limited final sample size did not allow for some of the planned, more sophisticated analyses involving moderators.

The research group trained, in collaboration with developers of the method, 51 experienced mental health professionals, including medical doctors, psychologists, psychotherapists, psychiatric nurses, and social workers, in NET. The trained therapists worked at different treatment units responsible for treatment of posttraumatic symptoms of children and adolescents at different levels, from primary care to specialized inpatient units. Three three-day trainings took place over three consecutive years (2014–2016). The trained therapists received the training gratis in exchange for agreeing to aim to recruit two participants for the study each. The therapists also collected data and carried out assessments with the patients they were treating. In line with principles of pragmatic trials (Thorpe et al., 2009), the researchers got involved in the treatment practices as little as possible.

Recruitment of participants for the study took place between January 2015 and June 2017, and data collection ended in February 2018. The inclusion criteria were 1) between 9–17 years of age, 2) referred to treating unit because of trauma-related mental health problems, 3) active PTSS, confirmed by the therapist based on his/her evaluation and the self-report measure used. A diagnosis of PTSD was not required. Exclusion criteria were 1) psychotic disorders, 2) current severe substance abuse, 3) severe suicidal ideation, and 4) intellectual disability. Randomization was by sealed, opaque envelopes. The research group provided participating clinics with folders, each containing all the relevant material and questionnaires for one participant as well as an envelope with a piece of paper reading either NET or TAU inside. We provided two folders, one for NET and one for TAU, per therapist. Whenever a clinician identified a child or adolescent coming to them for treatment as a potential participant, they provided information about the research and the interventions involved to the participant and their parents or guardians. If they were willing to participate in research and provided informed consent, they took a folder in random and opened the envelope to determine whether the participant would receive NET or TAU. Not all trained therapists were able to recruit participants for the study over the one to three year recruitment period.

All children and adolescents that agreed to participate were assessed at the start of their treatment (pretreatment) and at the end of their treatment three months later (posttreatment). We also planned assessments for halfway through the treatment and at three-month follow-up. However, there were marked challenges in data collection at these time points. As a result, a notable share of data was missing for the

midtreatment assessment (a total of 57% of data missing for the measures used in Study IV), and follow-up data could only be collected from 22 participants. We made no attempt to blind participants to the type of treatment they received, and as clinicians acted as data collectors, they could not be blinded either.

Figure 5 presents the flow of participants in the study. Initially, clinicians identified 54 children and adolescents eligible to participate, of whom four declined. The sample at baseline thus consisted of 50 children and adolescents between 9–17 years of age (M = 13.2, SD = 3.2), with 29 boys and 21 girls. Of this sample, 37 (74%) were refugees or asylum seekers with experiences of war or refugeedom and 13 (26%) were children of Finnish background with experiences of family violence. Apart from Finland, the most common countries of origin were Iraq (n = 14) and Afghanistan (n = 14). Participants had experienced multiple forms of serious trauma. Of the refugees and asylum seekers, 81% had experienced violence by a stranger and 57% physical abuse by caretakers, 35% had been imprisoned or held captive, and 73% had had family members exposed to violence or torture. All children of Finnish background had experienced physical abuse by caretakers, 46% sexual abuse, and 54% neglect of basic needs.

Despite randomization, the NET and TAU groups were somewhat unequal in size, with 29 in the NET group and 21 in the TAU group initially. This could have been simply due to chance, as with 50 participants there is an about 10% chance of 29 or more of them being randomized into one group. However, it is also possible that some external factor affected the process. For example, it is plausible that clinicians whose first patient was randomized to NET were less likely to actively try to recruit another patient, which would have resulted in less patients in the TAU group. We did not detect any particular irregularities in the randomization process, but they cannot be completely ruled out as explanations either, as clinicians carried out the randomization at their own units. In any case, there were no significant differences between the NET and TAU groups in gender distribution, age, country of origin, or mental health (PTSS, depressive symptoms, psychological distress, resilience) at baseline.

There were seven dropouts during the study, and three more participants completed treatment but did not contribute data at posttreatment. In Study III, we included all participants with data available at posttreatment in primary effectiveness analyses for each outcome and all available data from all participants who were initially randomized to either group in intention-to-treat analyses. For Study IV, examining mechanisms of change, we included only those participants who had completed treatment and for whom some posttreatment measures in PTSS, PTCs

and/or quality of traumatic memories were available. Thus, the final sample for Study IV consisted of 40 children and adolescents, 19 girls and 21 boys, 9-17 years of age (M = 13.3, SD = 3.1), of whom 10 were born in Finland and had experiences of violence in the family and 30 were born outside Finland, mostly in Iraq (n = 11) and Afghanistan (n =11). Of this sample, 23 received NET, while 17 completed TAU.