Background: The first years of life are a significant period for child development, when children are particularly sensitive and prone to crises. This early phase lays the foundation for healthy growth. Clinical assessment of psychological symptoms in early infancy and adequate treatment are both important in improving the diagnostic outcome and preventing later long-term developmental consequences. The most common psychological problems in the first 3 years of life are regulatory disorders. The aim of this trial is to investigate the efficacy of Parent-Infant Psychotherapy (PIP) for infants and young children (aged 0–36 months, diagnosed with at least one regulatory disorder) and their mothers, compared to care as usual (CAU).Methods: In this open multicentre randomised controlled trial, 160 mother-infant dyads are randomised to receive PIP or CAU for 6 weeks of intervention in clinical or outpatient (including home treatment) settings. The primary outcome is the maternal sensitivity (sensitivity scale of the Emotional Availability Scales (EAS)) after 6 weeks. Secondary outcomes include assessment of interaction, mental health problems, attachment, development, psychological factors, treatment adherence, health care system utilisation, and costs, after 6 weeks and 12 months.Discussion: This study will evaluate whether a manualised focus-based short-term psychodynamic psychotherapeutic intervention in mother-child dyads improves the care situation for families of children diagnosed with regulatory disorders, and helps prevent long-term psychopathologies. Assessment of the intervention in different settings will support the development of more tailored interventions for affected infants and their mothers.Trial registration: German Clinical Trial Register, ID:DRKS00017008. Registered 03/20/2019.

Maternal capacity to mentalize (= reflective functioning, RF), secure attachment and emotionally available parenting has an impact on the child’s development. The transmission of mothers’ past attachment experiences gained with both her caregivers in her own childhood and the impact on current mother–child interaction is part of the ‘transmission gap.’ This study explores the transgenerational transmission mechanisms and the potential moderating effect of RF in a clinical sample of 113 mother–child dyads suffering from mental health problems. In a cross-sectional study, the associations between maternal attachment experiences, RF (coded based on Adult Attachment Interviews) and current mother–child interaction (Emotional Availability Scales) were examined with univariate correlation, moderator analyses, and structural equation models. We found relationships between attachment experiences and mother–child interaction, but RF had no moderating effect. Past loving experiences and perceived neglection, particularly with the own father in childhood, were predictors for the present mother–child interaction. There seems to be an intergenerational transmission of attachment experiences to the ongoing generation. Particularly past adverse childhood experiences with the own father seem to explain currently disruptive interactions with the child.Trial registration: DRKS00017008 and DRKS00016353.

The COVID-19 pandemic and the ongoing lockdowns might have had a strong impact on mental health of mothers and their infants/toddlers. For example, families had to deal with health issues and social isolation, which might have affected mental health and parent-child interactions. The aim of this study is to evaluate differences in (1) infantile regulatory disorders, (2) maternal mental health, (3) the impact of maternal mental health on infantile regulatory disorders, and (4) alterations in the mother-child interaction for participants recruited before versus after the onset of the first German lockdown. For this reason, mother-child dyads have been divided into two groups and were compared by analyzing clinical interviews on psychopathology of mother and child (M.I.N.I. & DC:05) and mother-child-interactions (Emotional Availability Scales). Results showed that (1) differences in infantile sleeping disorders emerged (phi = 0.243; p = 0.016) compared to the pre-lockdown group, while (2) the occurrence of maternal panic and anxiety increased in the post-lockdown group (phi = 0.229; p = 0.022). Moreover, there was (3) an association for maternal panic and child’s sleep disorder, and (4) specific associations with maternal non-hostility in the mother-child-interaction. In conclusion, the present study highlights the differences of maternal mental health occurrences and infants’ regulatory problems, as well as the possible effects of the COVID-19 pandemic for infants. In the pre-lockdown group, maternal non-hostility might have acted as a promotive factor against regulatory disorders, while this mechanism was mitigated in the post-lockdown group.