The aim of the CAPEDP trial was to evaluate, in young primiparous mothers presenting vulnerability factors associated with greater likelihood of child mental health disorders, the impact on infant mental health of a home-visiting program conducted by trained psychologists and targeting the major modifiable determinants of infant mental health.

The program evaluated three primary outcomes: child mental health at the age of two, as well as two potential mediating variables: maternal postnatal depression at three months postpartum and the quality of the home environment when the child was 12 months old.

Secondary objectives included evaluating the impact of the intervention on: maternal postnatal depression at 6 months postpartum, infant attachment quality at 18 months of age, the mother’s quality of attachment at her child’s second birthday, her knowledge and use of social, medical and educational support services, her perception of receiving support from her own personal network, her parenting perceptions and behaviour, the child’s psychomotor development, sustained withdrawal behaviour of the child at 18 months, the mother’s knowledge concerning child development, her parental stress concerning caring for her child, her access to training and employment, her own psychological health and, in the intervention group, the working alliance between the mother and the home-visiting team (Table 1).

* in the intervention group only.

^# in the CAPEDP-A subsample only.

Assessment of attachment security and caregiver behaviour being particularly complex from a procedural point of view, an ancillary study involving a subsample of the CAPEDP population was designed to investigate this particular point: the CAPEDP Attachment (CAPEDP-A) Study. The objectives of this ancillary study were to assess the impact of the CAPEDP intervention in terms of increasing infant attachment security and maternal reflexive ability and reducing infant attachment disorganisation and maternal disorganizing behaviour when the child was from 12 to 15 months old.

Eligibility criteria limited participation to mothers in situations of medium to high vulnerability with regard to their future child’s mental health. All consecutive women consulting in the second trimester of pregnancy (from 12 to 27 weeks of amenorrhea) in ten public maternity wards were assessed for eligibility. Pregnant women were eligible if they were: living in the intervention area (Paris and its inner suburbs); sufficiently fluent in French to give valid informed consent, benefit from the intervention and participate in assessment sessions; less than 26 years old; first time mothers; less than 27 weeks pregnant at their first home visit assessment session; eligible for legal national health insurance or its equivalent for non-French participants (as required by French law on clinical research). They also had to declare at least one of the three following criteria: 1) having less than twelve years of education, 2) intending to bring up their child without the presence of the child’s father, and 3) having low income, defined as being eligible for French social welfare health insurance (Couverture Maladie Universelle Complémentaire) i.e. with an income less than or equal to 850 euros a month or, for undocumented migrants, Government Medical Aid (Aide médicale d’Etat).

Exclusion criteria were: women who would be impossible to follow up, such as Roma, gypsies, travelers, the homeless, or temporary refugees; women already receiving sustained social or medical care for other reasons than the above inclusion criteria (such as addictions or mental or physical disorders requiring close long-term follow-up); and women who did not consent to participate.

Participation in the study was proposed to eligible women in the waiting rooms of each maternity hospital, prior to a prenatal appointment. During this interview or at a second appointment if she asked for more time to make up her mind, the future participant signed the informed consent form.

After completing baseline screening and informed consent procedures, participants were randomly assigned in a 1:1 ratio to either the CAPEDP intervention or the usual care group using a computer-generated randomisation sequence, stratified by recruitment centre, with random block sizes of 2, 4 or 6 participants. This sequence was centrally generated by the Clinical Research Unit of Bichat Hospital, Paris, France. Assignment of participants was concealed using centralized randomisation through fax in the Clinical Reseach Unit. Investigators thus had no knowledge of the next assignment in the sequence in this open label trial. Investigators, psychologists performing the CAPEDP intervention and participants were blinded to assignment before, but not after, randomisation, as per the open-label design. However, in accordance with PROBE methodology, the outcome assessors were blinded to assignment and no investigators, psychologists or participants had any knowledge of aggregate outcomes at any point during the course of the study.

The intervention sought, where possible, to act upon the major modifiable determinants of infant mental health from the third trimester of pregnancy to the child’s second birthday. Intervention strategies were based upon three main theoretical concepts: parental empowerment, attachment security and Fraiberg’s developmental guidance and Ghost in the Nursery concepts 60 . With regard to parental empowerment, the programme manual used Rappaport’s 61 definition of empowerment as being made up of four components: participation, competence, self-esteem and personal and collective consciousness. The intervention thus specifically targeted mothers’ use of their personal community networks, their parenting skills, and their knowledge and use of available resources within the generous French social and health care context. Bowlby 62 defines attachment as a primary drive, a search for security through physical closeness when the child is in distress due to pain, hunger, stress, fear or separation. Depending on their mothers’ sensitivity and responsiveness to signals of distress, children develop, as early as 12 months of age, different styles of attachment. Secure attachment has been linked with increased resiliency, whereas insecure attachment and, even more so disorganized attachment, are associated with increased internalized and externalized psychopathology 63 64 . Increasing security of attachment and decreasing attachment disorganization were key intervention targets. Finally, providing social and emotional support within a solid working alliance to isolated, young mothers, often with difficult childhood experiences and high levels of postnatal depression, helped to connect the mothers’ past experiences with their behaviour when interacting with their child, thus uncovering potential ‘Ghosts in the nursery’ and helping young mothers explore new ways of relating to their children.

As indicated above, a major specificity of the CAPEDP intervention was that the home-visiting intervention and its evaluation were entirely conducted by trained psychologists. Eleven psychologists were recruited and assigned to either the intervention team (n = 7) or the assessment team (n = 4). All home-visiting psychologists received intensive training on implementing the CAPEDP intervention. Using the theoretical bases described above, the intervention was tailored to target, in terms of maternal empowerment, mothers’ knowledge and skills with regard to parenting, their ability to make the most of the care system, and their involvement with their own personal and local community networks. In terms of mother-child relationships, increasing security of attachment and decreasing attachment disorganization were key intervention targets. Finally, home-visiting psychologists received training on providing social and emotional support to the mothers within a solidly constructed working alliance, and helping mothers connect their past experiences with their current behaviour when interacting with the child, identifying ghosts in the nursery and exploring new ways of relating to their children. Manualised, but tailored to each family’s needs, the intervention targeted objectives specific to each child development period: prenatal, 0 to 3 months, 3 to 6, 6–12, and 12 to 24 months. The manual drew from Weatherston’s work on home-visiting and reflective supervision 65 , the Florida State Partners for a Healthy Baby Home Visiting Curriculum 66 , and the Steps Towards Effective Enjoyable Parenting (STEEP) attachment-based program 67 . Extensive use was made of McDonough’s developmental guidance approach through the use of video clips, filmed and discussed with the mothers 68 . Visits included showing mothers films on different aspects of parenting, from delivery through the different stages of child development. Further details of the content of the intervention can be found elsewhere 69 . Training also included a specific section on ethics and research procedures.

The program was designed for psychologists to visit families six times during the antenatal period, eight times in the first three months of the child's life, 15 times when the child was between 4 and 12 months of age and another 15 times during the child's second year, resulting in a total of 44 home visits during the whole intervention. Between visits, phone calls could be made as often as necessary.

Each psychologist doing home visits had weekly individual supervision with a member of a team of psychiatrists and psychotherapists, as well as group supervision with the main investigator (AG) to assess and react to situations of danger whether it be for the children (abuse, neglect, developmental delay, etc.) or their mothers (psychopathology requiring specific help, suicidal thoughts, special health needs etc.). Home visitors were encouraged to refer to the main investigator if they felt the slightest danger, if they felt distressed or if they felt that a situation was getting out of hand in any way.

Usual care, as described above, involved free access to the PMI network and to community mental health services, free antenatal maternity screenings by local GPs, extensive social security allowances and facilitated access to housing.

Families in the control group received usual care and seven assessment home visits across the trial period. The intervention group, in addition to usual care and assessment visits, received the CAPEDP home-visiting program. Assessment visits were conducted during specific home visits by a team of four trained and supervised psychologists, working independently from the psychologists performing the CAPEDP intervention, and with no prior knowledge of whether the families they were assessing were in the intervention group or the control group. For each family, seven home-based assessment visits were scheduled across the trial period, at the 27^th week of pregnancy, and then when the child was 3, 6, 12, 18 and 24 months old. All measured outcome criteria and the month at which these were measured are presented in Table 1. The assessment team received specific training on the use of all assessment instruments. Individual and group supervision was provided for all members of the assessment team, to give them support when faced with difficult situations during evaluation. Evaluators who observed significant problems or risk situations, either for the mother or for the child, in any family were instructed to seek immediate advice from the principal investigator. Families were referred to immediate care and support if necessary.

At baseline and, if appropriate, at follow up visits, the following data were collected: socio-demographic data including standard questions on age, sex, marital status, ethnicity, household composition, composition of the mother’s family, characteristics of the partner and, if different, the child’s father, whether the pregnancy was desired or not, number of years of education, educational level achieved, employment status, and income; health variables including mothers’ perceived state of health, and tobacco, alcohol or drug consumption. Neonatal data concerning the child and childbirth were collected while the mother was still in the maternity ward after giving birth.

As mentioned above, the study had three primary objectives: child mental health at the age of two as well as two potential mediating variables: maternal postnatal depression at three months postpartum and the quality of the home environment when the child was twelve months old.

Child mental health at the age of two was assessed using the Child Behavior Checklist 1½-5 (CBCL 1½-5) 70 . This instrument is widely used to assess psychopathology in infants and toddlers. A recent validation study in 23 societies, including the French translation and validation used in the present study, confirmed transcultural validity 45 . It is a 100-item scale, divided into seven syndrome subscales.

Maternal postnatal depression was assessed using the Edinburgh Postnatal Depression Scale (EPDS) 40 . This is a 10-item self-report questionnaire designed to be completed in the presence of an observer. It is valid for assessing both pre- and postpartum depression. The EPDS has been validated in a French population 71 . Different EPDS threshold scores were used to distinguish between depression and major depression.

The quality of the home environment when the child was 12 months old was assessed using the Home Observation for the Measurement of the Environment (HOME) 42 . This is a well-known and widely-used scale assessing the quality and quantity of stimulation and support available to a child in the home environment. As recommended, scoring was conducted during a home visit which did not have scoring the HOME as its unique objective.

Secondary outcome measures are described in Table 1.

The CAPEDP-A study assessed infant attachment quality, maternal disrupting behaviour and parental reflexive capacity using the Insightfulness Assessment (IA) interview.

Infant attachment quality was assessed using both the Strange Situation Procedure (SSP) 57 in our laboratory and the Attachment Q- Sort procedure 46 , during a home visit. The SSP was used only in the CAPEDP-A subsample because of its complexity and time-consuming scoring. The procedure took place in an attachment assessment laboratory created specifically for this purpose in the research centre. The SSP proposes a fixed sequence of eight episodes, each lasting three minutes, designed to activate and/or to intensify the attachment behaviour of one year old infants. The procedure involves two brief separations and two reunions between the infant and their attachment figure, in the present case, their mother. Each procedure was video-taped. The procedure was coordinated by a senior psychiatrist trained in the use of the instrument and its coding. Psychology residents acted the roles of the strangers. The assessment of infant attachment quality using the SSP identifies three categories of attachment patterns. The insecure-avoidant group (A) is characterized by the infant avoiding manifesting attachment behaviour towards the attachment figure. The secure group (B) includes infants who evidence active proximity-seeking and interaction with the attachment figure, especially in reunion episodes. The insecure resistant/ambivalent group (C) is characterized by the coexistence of active contact resistance behaviour and proximity-seeking or contact-maintaining behaviour with the attachment figure. Coding of the procedure was made on video recordings by independent raters who were blinded to randomisation groups to reduce subjectivity-related variability. One assessment team and three coding teams were established. Coders had no direct contact with any dyad and were not aware of the group (intervention or control) to which the dyads belonged. Each measure was coded by separate coders. Furthermore, two independent coders coded a random selection of 30% of the cases. Inter-observer concordance calculated using Cohen’s Kappa coefficient was satisfactory (kappa = 0.79). Disagreements were discussed and a consensus category was attributed to the dyads in question. The SSP recordings were also used to assess disorganized attachment. Assessment was conducted by one of the authors (ST), who was specifically trained and validated for this coding.

Maternal disrupting behaviour was assessed using the Atypical Maternal Behavior Instrument for Assessment and Classification (AMBIANCE) scale 58 . This 5-dimension scale, scored on the SSP procedure video, measures a broad range of maternal behaviors that can be potentially disorganizing to infants' attachment. Higher scores reflect higher levels of maternal disorganising behaviour when attachment issues are raised. The scoring team was trained by Karlen Lyons Ruth and Elisa Bronfmann, the creators of the AMBIANCE scale, in a training session in Paris in 2008 and demonstrated full reliability. AMBIANCE coders were different from SSP coders and blind to the randomisation group of the families being assessed.

Parental reflexive capacity was assessed using the Insightfulness Assessment (IA) interview 59 . This is a semi-structured interview concerning the mother’s capacity to see things from the child’s point of view. It is assessed after she has viewed a video clip of herself with her child (nappy changes, free play, feeding or SSP). The IA is scored using ten sub-scales, and results in a classification into four categories. Each dyad was video-taped for SSP, nappy change, feeding and free play. The four IA raters achieved reliability on IA rating during a specific 2007 training with the team that created the instrument. Raters for IA were blind to the randomisation group of the dyad. The IA interviews took place at the same time as the SSP, when the infant was from 12 to 15 months of age.

Psychologists were asked to keep case notes on each home visit. These will be used to evaluate the frequency of the different themes that were notified as discussed during the home visit, the home visitor’s subjective perception of the visit, and the extent to which the home visitors’ preoccupations during that visit corresponded to the intended intervention.

Participants were informed that they could withdraw at any time for any reason. In order to optimise adherence to the intervention, families were reminded of upcoming visits by phone or with a text message. Missed home visits were rescheduled within the following week. Home visitors were also encouraged to maintain telephone contact with families between visits. Families that regularly missed home visits or did not respond to phone calls continued to receive regular calls at least once a fortnight from their home visitor. These calls continued through to the end of their planned participation in the study. Letters were regularly sent to each family that had not been in direct contact with their home visitor for a period of over three months without giving news. All participants, including those lost to follow up by the intervention team, were contacted by the evaluation team at every assessment point (at 3, 6, 12, 18, 24 months). In cases where families accepted phone contact but were reticent to receiving any further home visits, assessment took place over the telephone, except for those instruments that required direct observation. If phone contact proved to be impossible, questionnaires were sent to families via the post.

The study was designed and carried out in accordance with the principles of the Declaration of Helsinki, 5^th revision 74 . The study protocol was approved for all centres by the Institutional Review Board ‘Comité de Protection des Personnes Ile de France IV’ (IRB authorisation 2006/37). Written informed consent was obtained from all participants before inclusion. The trial is registered as ClinicalTrials.gov number NCT00392847.

The study received ethics approval (CPP Paris Saint Louis, advice n° 2006/37) and grants from major funding bodies: CAPEDP was supported by research grants from the French Ministry of Health Programme Hospitalier de Recherche Clinique (PHRC: AOM05056), the Institut National de Prévention et d’Education à la santé (INPES: DAS 08/2006 DAS 018/09 DAS 084/10), the Institut de Recherche en Santé Publique (IReSP: REV0702). The clinical trial number is NCT00392847.

The sponsor was the Département à la Recherche Clinique et au Développement, Assistance Publique–Hôpitaux de Paris.