Infant mental health: evidence review

Key Findings

Definitions of infant mental health vary

This report has been informed by the Scottish Government PNIMH Programme Board (2020) and the report defines infant mental health as: The child's ability to develop socially and emotionally from conception up to the age of three.

It is important to note however that definitions of infant mental health vary, with differences in conceptualisation falling mostly under two main categories:

a. social and emotional development up to the age of three (AIMH, n.d.) and

b. social and emotional development up to the age of five (Clinton et al., 2016).

However, the majority of prominent organisations, such as AIMH and ZERO TO THREE, as well as notable mental health theorists (e.g., Zeanah et al., 2005; Lyons-Ruth et al., 2017) tend to define infant mental health as social and emotional development up to the age of three.

The complexities of developmental sensitivity of infants and young children can pose difficulties in defining a suitable age range – for example, toddlers are often classified as both infants and/or young children. This is evidenced by publications such as the Mental Health of Children and Young People Survey (NHS, 2018) which reported prevalence rates of mental health disorder in preschool children, defined as 2-4 year olds.

While ZERO TO THREE (n.d.) define infant mental health as social and emotional development from birth to three, they also use the term "infant and early childhood mental health (IECMH)" (2016) to describe social and emotional development from birth up to the age of five, implying that while there is some relevant overlap, there are clearly notable differences between these two unique stages of development (ie. infancy; 0-3 years, and early childhood; 3-5 years). This concept is also supported by WAIMH who have argued that "there are unique considerations regarding the needs of infants during the first three years of life" (2016, pg3).

Research identifies a number of factors as contributing to IMH which fall under a few key categories:

• Secure relationships

Infants and young children are dependent on the people who take care of them. The predictability that comes from a secure attachment with at least one caregiver can lead to stress and emotion regulation in infancy and beyond, which in turn can contribute to a sense of mental wellbeing across the lifespan (Doyle & Cicchetti, 2017; Naughton et al., 2019). It is important to note that the majority of research suggests that promoting IMH can be best achieved by promoting positive relationships between infants and young children and their caregivers (Clinton et al., 2016; Love & McFadyen, 2021).

• Safe and stimulating environments

Infants and young children are at risk of developing poor mental health if the environment they are living in is unsafe or stressful. Adverse childhood experiences (ACEs) and a traumatic environment can lead to a child developing anxiety and depression, PTSD, as well as other negative externalising and internalising behaviours, such as aggression or social withdrawal (Lyons-Ruth et al., 2017). Environments affected by neglect, poverty, or violence are not only risk factors for a child's physical and emotional development, but are also likely to put a strain on the developing relationship between baby and caregiver (Clinton et al., 2016).

• Emotion regulation

ACEs have also been shown to impact on the child's temperament (McDonald et al., 2019). While a child's temperament will have an impact on their internalising and externalising behaviours, the way that a caregiver is sensitive to the needs of the infant can mitigate self-regulation problems as the child develops (Lyons-Ruth et al., 2017). Interactions between infant and caregiver that allow the infant to regulate their behaviour in a safe and exploratory manner will lead to positive mental health trajectories and a developed sense of self (Housman, 2017).

• Clinical diagnoses

While it may be more difficult to identify symptoms associated with mental health disorders in infants (Szaniecki & Barnes, 2016), it has been suggested that extended periods of irregular sleep patterns, feeding problems, and excessive crying may all be indicators of mental health disorder in infants, independent of maternal mental health risks (Olsen et al., 2019). Additionally, into toddlerhood, it is also possible to screen for more explicit clinical diagnoses, such as pervasive developmental disorders (PDD), autism spectrum disorders (ASD), and hyperactivity and inattention disorders (ADHD).

• Social determinants of health

As noted above, the infant is wholly dependent on the caregivers they are living with and the environment that they are living in, and so when measuring IMH it is also important to consider social determinants of health pertaining to the whole family, as well as the particular situation and the mental health of caregivers (Lyons-Ruth et al., 2017). Ethnicity and social economic status have both been identified as social determinants of health associated with parental and child mental health (Klawetter & Frankel, 2018), and research has long held that families living in disadvantaged circumstances are often forced to contend with the compounding effect of multiple socio-political risk factors (Sameroff & Seifer, 1995). Many infant mental health issues, such as irregular sleep patterns as well as feeding and eating disorders are associated with social determinants of health (Hvelplund et al., 2016).

Considerations for measuring infant mental health

As previously noted, this report defines infant mental health as the child's ability to develop socially and emotionally from conception up to the age of three. As per the report's definition of infant mental health, measures were only included in this review if they are validated for use with children under 3 years old. However it should be noted that a number of the measures that have been identified in this report are used with children with an age range of 0 – 66 months. Across the 18 papers, 11 measures were identified that are validated for use in screening for IMH issues within the defined scope of the report (see Annex B for details of the measures identified).

The measures identified within this review are mainly structured as checklists and questionnaires (see Annex B for more detail). While a number of observational measures which take the relationship between infant and caregiver into account are available, such as the Parent-Infant Interaction Observation Scale (Naughton et al., 2019), the Strange Situation Procedure (Ainsworth et al., 1978) and the CARE-Index (Crittenden, 1981), these are lengthy processes, both in terms of training and application, and as such are normally reserved for academic research rather than healthcare practice (Sleed et al., 2021) and so have been excluded from this report.

A number of factors were identified as possible considerations when deciding whether a measure is appropriate for use in clinical and health settings. These factors include:

a) accessibility,

b) measurement across domains and age ranges,

c) screening for internalising and externalising behaviours at an early age, and

d) time, cost, and access constraints.

• Accessibility

Accessibility is important when working with parents to promote the mental health needs of their child. How measures are worded can make a difference, and simple wording such as that in the Ages and Stages Questionnaire (ASQ; Squires et al., 2015) allows parents to engage with the measure in a meaningful way (Szaniecki & Barnes, 2016). Additionally, the content of the questionnaire may need to be designed differently to that of an adult mental health measure. Parents may feel anxious about labelling their child as having behavioural problems (Eneberi, 2017) and so measuring competencies as well as difficulties can lead to mental health promotion rather than mental health stigmatisation (Szaniecki & Barnes, 2016).

• Measurement across domains and age ranges

The current research shows that there are a number of measures available to use across domains and age ranges. Trying to capture the sensitivity of development at such an early age means that a number of different behaviours may need to be observed in a very short space of time. For example, problematic behaviour in a 4-year-old could often be classified as normal behaviour for that of a 2-year-old. This may mean that different measures are employed as children progress throughout infancy and into toddlerhood. Using different measures may therefore mean that domains are tested differently, which can result in difficulties in identifying and tracking developmental problems over time (Eneberi, 2017; Patel et al., 2021).

• Screening for internalising and externalising behaviours at an early age

Some measures, such as the Child Behaviour Checklist (CBCL; Achenbach & Rescorla, 2001) and Strengths and Difficulties Questionnaires (SDQ; Goodman, 1997) have been validated for a larger age range and thus may have more longitudinal sensitivity (Patel et al., 2021). The SDQ, however is only validated for use in children aged 2 years and over. In an attempt to screen younger children, adaptations and downward extensions of the SDQ:2-4 have been trialled to validate the measure for use with infants aged 12-24 months (Eneberi, 2017; Patel et al., 2021). While there has been some success within the trials, it has been suggested that using the SDQ with children under 2 years old may be better at screening for externalising rather than internalising behaviours (Patel et al., 2021). One of the reasons for this could be that measuring internalising behaviours in infants is more difficult as parents will need to employ more guesswork to infer their baby's behaviours and intentions (Eneberi, 2017).

• Time, cost, and access constraints

All of these factors are important when considering what measures should be used in clinical and health settings. Additionally, in real world settings, there are time and resource constraints placed on practitioners which cannot be ignored. Structured checklists can be filled out more quickly and long form questionnaires are likely to provide more sensitive screening of IMH issues in the general population. However, adapted brief measures may be more relied upon in settings where time is limited. Practitioners may also not have the time to invest in long periods of training which are necessary for some measures (Naughton et al., 2019). Cost and access issues can also cause barriers, with a number of measures considered as 'gold standard' held under copyright (for example, CBCL, ITSEA. ASQ). Potentially, practitioners may need to compromise on sensitivity in exchange for a time and cost effective measure (Szaniecki & Barnes, 2016).