The large proportion of young children in the foster care population is of concern, with children younger than five years old representing over a third of foster children in the US (33% of 400,540 [
1]) and the Netherlands (36% of 8,944 [
2]). Children often enter foster care after serious neglect and abuse. Among foster children, there is wide variation in behavioral and relationship functioning, which is on average more problematic compared with that of children living with biological parents [
3‐
5]. Foster children often suffer from post-traumatic stress disorder [
6] as well as more complex traumatic symptoms [
7], more disorganized attachment [
8], and high frequencies of clinical symptoms of disturbed attachment [
9‐
11]. Additionally, adverse or inconsistent caregiving tends to cause atypical functioning of children’s biological stress systems, such as changes in the hypothalamic-adrenal-pituitary (HPA) axis, represented by abnormal cortisol segregation [
12,
13], and altered stress regulation activity of the autonomic nervous system (ANS) [
14]. After placement in foster care, problems tend to persist or even worsen [
15,
16], and not only negatively affect the parenting behavior of foster carers [
17] but also increase the risk of placement breakdown. Placement breakdown may start a vicious circle in which the chance of another failure increases with every breakdown [
18]. The last alternative is often residential placement, which fails to provide opportunities for developing attachment [
19], causes developmental delays [
20], and places children at further risk. To prevent foster children from further problems, these children are in need of evidence-based programs that combine foster placement with effective treatment of emotional and behavioral disorders and parental stress. Multidimensional Treatment Foster Care for Preschoolers (MTFC-P) tends to address these needs, providing a positive and stimulating foster family setting for these children. Foster caregivers are taught effective behavioral management strategies and children receive individually tailored behavioral interventions. Dozier and Rutter [
21] suggested that when foster carers and children gain control over behavioral problems, the potential for the development of a (secure) attachment relationship increase. The absence of behavioral problems results in less parental stress for the foster carers, allowing them to better respond to the child in a sensitive and nurturing way - supporting children’s belief in the caregiver’s availability. With the increase of (secure) attachment behaviors, the risk of disturbed attachment declines, because behaviors of either type are theoretically incompatible with one other [
11,
19].
Previous studies in the US have shown that, relative to children in regular foster care, children in MTFC had fewer placement failures [
22], improved HPA axis functioning [
23], increased secure attachment behavior and less resistant behavior [
24]. Although MTFC-P is quite successful in the US and transportability of the MTFC model for older children has been shown in a Swedish context [
25], the efficacy of the preschool version has not been replicated in other countries where implementation challenges and cultural differences may play a role. Outside the US, in the Netherlands, only a small pilot study was conducted, preliminary to this study. Early findings suggested less problem behavior in the MTFC-P intervention [
26].
This protocol is for a study intending to examine whether US findings regarding MTFC-P also apply for children in foster care in the Netherlands. The study also aims to extend on previous studies by examining the effects of MTFC-P on post-traumatic stress symptomatology, symptoms of attachment disorder and quality of life. With the present study, we compare the effects of MTFC-P with a treatment as usual (TAU) for foster children at risk for placement breakdown. We hypothesize that MTFC-P is more effective than TAU for young foster children with emotional and behavioral disorders. Effectiveness is measured in terms of decreased problem behavior; fewer symptoms of disturbed attachment; fewer severe post-traumatic stress symptoms; improved quality of life; recovery of HPA-axis functioning, indicated by recovery of atypical cortisol activity; and less parental stress. We expect that, relative to control children, at the end of the treatment children in the MTFC-P group will show less maladaptive responses of the ANS, indicated by heart rate, respiratory sinus arrhythmia and pre-ejection period, to separation and reunion with caregivers and strangers.