The Michigan Association for Infant Mental Health has listed the following core infant mental health beliefs that are the cornerstone for infant mental health practice [6]:

The concept of "ghosts in the nursery," originally developed by Selma Fraiberg and colleagues, speaks to the impact of intergenerational parenting practices, experiences, and events [1]:

In every nursery, there are ghosts. They are the visitors from the unremembered past of the parents, the uninvited guests at the christening. Under favorable circumstances, these unfriendly and unbidden spirits are banished from the nursery and return to their subterranean dwelling place. The baby makes his own imperative claim upon parental love and, in strict analogy with the fairy tales, the bonds of love protect the child and his parents against the intruders, the malevolent ghosts.

There are many types of violence that can occur in a family, such as spousal abuse, child abuse and neglect, elder abuse, and caregiver abuse, and many families struggle with one or more types of violence and abuse. Witnessing or experiencing violence is scary and confusing. Children who are exposed to this type of violence may learn that the family unit is a source of harm instead of a source of safety and security [10]. This may lead children to mistrust those responsible for their care and to manifest symptoms of fear, anger, aggression, and poor affect regulation. Because infants and toddlers spend most of their waking hours with adult caregivers, these relationships are essential in shaping the infant's or toddler's view of the world and themselves. In 2022, the U.S. Department of Health and Human Services Administration for Children and Families published their annual report, Child Maltreatment2020, which indicated that the largest cohort of children experiencing childhood maltreatment (in the form of abuse and neglect) were younger than 3 years of age, with infants (younger than 1 year of age) at the greatest risk [11]. In total, 26% of children are exposed to family violence during their lifetimes [43].

Women who have difficult or degrading birth experiences may also manifest symptoms of post-traumatic stress disorder (PTSD). Delivery or post-delivery trauma can include an unplanned cesarean delivery, long-term separation of infant and mother after birth, medical interventions due to emergency or illness, and lack of caring by medical staff. The reported prevalence of birth trauma is 32%, with up to 6% of woman developing symptoms associated with PTSD [16]. Infant-preschooler mental health professionals can be a support for families who are struggling with maternal mental illness.

Research indicates that adults who were once foster children have a rate of diagnosed PTSD that is twice that of Vietnam veterans [21]. Children in foster care tend to have poor outcomes in regard to health and education as well. Without support and intervention from trauma-informed, relationship-focused professionals, infants and young children impacted by attachment disruptions in any form, especially those exposed to institutionalized care, are at risk for medical, behavioral, and emotional problems.

Healthy, secure attachment is the ideal pattern of attachment, and it is the most commonly observed type. Healthy, secure attachment is created when parents are available and attuned to the needs of their child, providing consistent care and maintaining a sense of safety and comfort for the child. When secure attachment is observed in a young child, the child may reference his/her parent for reassurance in new situations, take comfort from his/her parent, exhibit reciprocal interactions and joint attention with his/her parent, show emotional involvement, and visibly relax when with the parent. Of course, when observing for attachment, it is important to take into consideration variables that may impact the attachment style, such as developmental delay, attention deficit hyperactivity disorder (ADHD), autism, or brain injury/trauma.

When a child has a secure attachment with an adult caregiver, he/she will develop a mental representation (internal working model) of him/herself as lovable and psychologically coherent [24]. This process is essential for children to develop appropriate affect regulation and empathy. Additionally, secure attachment assists in developing self-esteem and confidence in oneself as a social being.

The Ages and Stages Questionnaires, Third Edition (ASQ-3) is a user-friendly instrument that can be easily completed by parents in 10 to 15 minutes [45]. Practitioners can assist in the completion of the questionnaire, if necessary. This tool focuses on five separate developmental areas: gross motor skills, fine motor skills, social-emotional development, problem-solving, and communication. The tool takes approximately two to three minutes to score. It provides an opportunity to focus on both a child's strengths and areas for growth. In addition to screening for developmental delays, the ASQ-3 system also includes a list of activities parents may engage in with their children to address developmental areas that may need additional support.

The Keys to Interactive Parenting Scale (KIPS) assesses the quality of parenting behavior for families with young children 2 to 71 months of age. This scale focuses on 12 behaviors related to effective parenting [49]:

The Marschak Interaction Method (MIM) is a structured assessment technique for observing the overall quality and nature of relationships between caregivers and children. It consists of a series of simple tasks designed to elicit behaviors in four primary dimensions (challenge, structure, engagement, and nurture) in order to evaluate the caregiver's capacity to [25]:

Because of the limitations of classification systems like the DSM and the ICD as they apply to infants and toddlers, a task force, Zero to Three, was created by the National Center for Infants, Toddlers, and Families in 1987. This task force, consisting of professionals in the fields of infant development and mental health, created the Diagnostic Classification of Mental Health and Development of Infancy and Early Childhood (DC: 0–3) in 1994 as a multiaxial system for disorder classification of young children [30]. In 2005, the revised version was published to reflect advances in disorder classification and increased emphasis on the effects of relationship characteristics, psychosocial stressors, and contextual factors on infant-toddler mental health and development [30]. In 2016, the Diagnostic Classification of Mental Health and Development of Infancy and Early Childhood was revised and expanded to include children up to 5 years of age [30]. The DC: 0–5 guides professionals to use diagnostic criteria for effective assessment and treatment planning for existing and newly introduced disorders. This manual has grown in popularity and is now a common tool for classification of early childhood mental health and developmental disorders.

The ABC Model is a structured, evidence-based approach whereby weekly one-hour sessions are provided for 10 weeks in the caregiver's home. Support and guidance is provided in the moment by the trained professional to focus on target behaviors. This intervention uses video feedback.

The toys in the playroom are carefully chosen, with special attention to including items that can be used in a multitude of ways. Items for creative expression (e.g., crayons, paints, construction paper), real-life toys (e.g., dolls, play money, medical kit), and aggression-release toys (e.g., soldiers, wild animals, clay) should be among the toys chosen for a playroom. (See the Appendix for a more complete list of toys and objects to include in a play therapy room.)

Filial play therapy was developed by Drs. Louise and Bernard Guerney in the 1960s as a treatment for children with behavioral, emotional, and social problems. Filial therapy is a form of family play therapy focusing on supporting parents to become primary change agents as they learn to conduct child-centered play sessions with their own children [34]. Like nondirective, child-centered play therapy, filial therapy follows the eight basic principles of play therapy [34]. This approach has been used with empirical support in children 3 to 12 years of age and occasionally with older children who have experienced trauma. Research is being conducted in utilizing the filial therapy model with younger children [35].

The essential features of filial therapy are [36]:

Child-parent psychotherapy (CPP) is a relationship-based intervention for trauma-exposed children 0 to 6 years of age. CPP is a culturally informed treatment, focused on strengthening the parent-child dyad to restore and protect the mental health of children. The goals of CPP are to improve the emotional attunement of the parent-child dyad and enhance interactional patterns [37]:

It targets for…unmodulated or dysregulated parental or child behaviors, particularly symptoms of violence-related trauma that include externalizing problems such as aggression, defiance, noncompliance, recklessness, and excessive tantrums, and internalizing problems such as multiple fears, inconsolability, separation anxiety, difficulties sleeping, and social and emotional withdrawal.

The DIRFloortime model is often used with children who have an ASD or who have other developmental disabilities. This comprehensive framework lends itself to a multidisciplinary approach by including team members such as occupational or speech therapists in the intervention.

Dr. Tiffany Field, founder of the Touch Research Institute at the University of Miami Medical Center, has completed many research projects on the value of touch and infant massage. In one research study, 20 preterm infants were massaged in the hospital, three times per day, for at least 15 minutes per massage. These infants gained 47% more weight and left the hospital on average six days earlier than their non-massaged counterparts. Additionally, the infants who received massages were noted to be more alert, more active, and showed significantly more mature neurologic development [39].

The core characteristics of Theraplay are [25]:

Reflective practice facilitation is the development of one's awareness of thoughts, feelings, and responses and the impact of these thoughts, feelings, and responses on young children and families. This approach speaks to the practitioner's ability to be present and mindful of the relationships at play in the life of a young child.

Administrative and/or clinical supervision differs from reflective practice supervision in that these types of supervision have a specific focus on reviewing and enforcing policies and procedures, monitoring productivity, evaluation, and documentation review. This is not to say that administrative and/or clinical supervision cannot be reflective in nature. In reflective practice facilitation, however, the focus is on the emotional exploration of the work with infants and toddlers. Additionally, reflective practice facilitation focuses on the parallel process and exploration of relationships (e.g., parent-child, practitioner-supervisor, practitioner-parent).

The Michigan Association for Infant Mental Health outlines the following points as paramount to reflective practice supervision [38]: