You may have heard about the developmental importance of ‘the first thousand days’ of a child’s life (Moore, Arefadib, Deery, & West, 2017). A growing body of evidence supports this thinking – that experiences in-utero, through infancy (0–12 months) and into toddlerhood (1–3 years) can have lifelong impacts, both positive and negative, for physical and mental health, literacy, numeracy and socio-economic outcomes (WHO Commission on Social Determinants of Health, 2008). These early years are vital in shaping a child’s long-term social and emotional wellbeing.
To support parents and children as they navigate these early years, it’s essential for practitioners to have a baseline understanding of infant and toddler development. It’s also important to recognise that parents may have varying understandings about how children develop – what constitutes ‘normal’ behaviour at different ages and stages, and what may be signs of mental health concerns.
In the first three years of life, development is characterised by rapid physical and cognitive growth (Healthwise, 2019). From birth, infants are on a fast-track in language and communication development, as they learn to interpret and adapt to the words, sights, sounds and smells that are all around them. Over these years, babies’ brains triple in weight, establish billions of cells and produce more than a million neural connections every second (National Center for Infants, Toddlers and Families, 2014). Physically during this period, children go from having very little control over their bodies, to crawling, standing, walking, then running (McLean, 2020).
A healthy child’s physical and mental development over the first three years is extraordinary. Key timeline milestones include the following (Department of Human Services, Victoria, 2014; Women’s and Children’s Health Network, South Australia, 2014):
- 0–2 weeks: Builds relationships through facial expressions, gazing and crying.
- Four weeks: Can follow an object and focus on a face.
- 6–8 weeks: Interacts with caregivers through vocalisation, eye contact, smiling and crying.
- Two months: Can lift head when lying on their tummy.
- 3–4 months: Will increasingly initiate interactions, reach for objects, laugh and hold their head up.
- Six months: Will use their carer for comfort and may roll over.
- Seven months: May be sitting up and starting to crawl.
- Nine months: May pull themselves up to stand, start to recognise emotions and experience separation anxiety.
- By 12 months: May talk in their own language or say a few clear words; can hold things between thumb and forefinger.
- 12 months: Enjoys communicating, understands more than they can verbalise, expresses more emotions and may walk.
- 18 months: Can use some words, needs structure and routine and is developing individuality.
- Two years: Likes to help; may build towers and engage in more complex play.
- Two-and-a-half years: Uses 50 or more words; alternates between clinginess and independence.
- Three years: Can throw a ball, speak clearly and carry out a conversation; may be toilet trained.
The rate of change, learning and adaptation across this time period is astonishing – and it’s clear that physical and mental development are inextricably intertwined.
In the following video (1 minute, 35 seconds), Dr Tim Moore talks about adaptation and learning in the first thousand days of life, and how biological and neurobiological development are linked to social and emotional wellbeing.
Beyond learning to communicate and control their bodies, the major developmental challenge for an infant is to form an attachment with at least one reliable caregiver who can respond to their physical and emotional needs – a bonding experience that forms the foundation for their later social, emotional and cognitive development (McLean, 2020). This formative connection gives a young child a sense of agency in their world, and of the ‘trustworthiness’ of others – an internalised ‘working model’ that forms the basis for self-awareness, self-esteem, and emotional, social and cognitive development (DeKlyen & Greenberg, 2008).
As an infant becomes a toddler, the basic sense of trust they have in their primary caregiver – the secure knowledge that someone will be there for them when needed – supports them to explore and learn beyond their primary attachment, and in the development of their sense of ‘self’ (McLean, 2020). It is this fundamental nurturing relationship between infant and caregiver – that the child’s wellbeing is the caregiver’s top priority – that sets children up for positive mental health later in life.
In the following video (29 seconds), parenting consultant Dianne Halloran confirms the importance of good nurturing as a building block for life-long social and emotional wellbeing.
Infant and toddler mental health can be defined as a young child’s capacity to experience, regulate, and express emotions, form close and secure relationships, explore the environment and learn (Zero to Three, 2001). If they are living in a setting that is responsive to their needs and stimulating to their development, most infants and toddlers learn to do all of these things and experience good mental health.
However, infants and toddlers are extremely vulnerable to disruptive and traumatic life events and parental adversities. Their wellbeing can swing from the ‘healthy’ end of the mental health continuum to ‘unwell’ very easily. When an infant or toddler’s early attachments with caregivers are disturbed or disrupted, it can impact on their willingness and confidence to explore, and therefore affect their social, cognitive, and physical development, in both the short- and long-term.
Risk factors working negatively against infant and toddler mental health can be grouped into three categories:
- individual factors, such as birth complications, injuries and temperament
- family and caregiver factors, such as parental mental illness or substance use issues; and
- environmental, social and community factors, such as natural disasters, poverty, limited educational and economic opportunities, unemployment or inadequate housing (Lawless et al., 2014; Piccolo & Noble, 2019; Zeanah Jr & Zeanah, 2019).
Many of these factors are beyond a parent’s or a practitioner’s control – and it’s no small irony that in these critical years, when infants and toddlers are totally reliant on their caregivers, it is often the struggles of caregivers themselves that can render children most vulnerable to poor mental health. Compounding this complex scenario, most Australian parents acknowledge that they do not know how to recognise or respond to mental health struggles in young children (Rhodes, 2017).
But many of these factors also present opportunities for parents and practitioners to make a positive impact on infants’ and toddlers’ mental health.
It’s imperative for practitioners to understand infants’ and toddlers’ vulnerabilities, in order to identify those children experiencing problems and provide early intervention. Current evidence advises that in situations where children are vulnerable, intervening early helps to improve their outcomes (Royal Australian and New Zealand College of Psychiatrists, 2010).
In supporting parents, particularly when mental health concerns are part of the picture, a key strategy practitioners can employ is ‘anticipatory guidance’ – providing parents with useful, relevant and practical information about ‘what to expect’ in an infant or toddler’s behaviour, growth and development in the immediate and longer term. Anticipatory guidance can equip parents with ways to provide positive experiences and environments for their infants, in turn reducing parental anxiety and promoting positive infant mental health and wellbeing.
When parents and practitioners intervene early and work together to understand development, support attachment, and mitigate risk factors that can negatively impact on an infant or toddler’s mental health, it can make a real difference to that child’s long-term outcomes.
In the following video (30 seconds), general practitioner Dr Penny Burns reinforces the idea of intervening early to support children’s mental health, to try and make a long-term difference.
DeKlyen, M., & Greenberg, M. T. (2008). Attachment and psychopathology in childhood. In J. Cassidy and P. R. Shaver (Eds.). Handbook of attachment: Theory, research and clinical applications (2nd ed., pp. 637–665). New York: Guilford Press.
Department of Human Services, Victoria. (2014a). Child development and trauma specialist practice resource: 0–12 months. Melbourne: Department of Human Services.
Department of Human Services, Victoria. (2014b). Child development and trauma specialist practice resource: 12 months – 3 years. Melbourne: Department of Human Services.
Healthwise. (2019). Growth and development milestones. Boise: Healthwise.
Lawless, A., Coveney, J., & MacDougall, C. (2014). Infant mental health promotion and the discourse of risk. Sociology of Health & Illness, 36(3), 416–431.
McLean, S. (2020). Understanding child development: Ages 0-3 years. Adelaide: Emerging Minds.
Moore, T. G., Arefadib, N., Deery, A., & West, S. (2017). The first thousand days: An evidence paper. Melbourne: Centre for Community Child Health, Murdoch Children’s Research Institute.
National Center for Infants, Toddlers and Families. (2014). Brain development. Washington: Zero to Three.
Piccolo, L. R., & Noble, K. G. (2019). Poverty, early experience, and brain development. In C. H. Zeanah Jr (Ed.), Handbook of infant mental health (4th ed., pp. 157–171). New York: Guilford Press.
Rhodes, A. (2017). Child mental health problems: Can parents spot the signs? Melbourne: Royal Children’s Hospital Melbourne.
Royal Australian and New Zealand College of Psychiatrists. (2010). Prevention and early intervention of mental illness in infants, children and adolescents: Planning strategies for Australia and New Zealand. (Report from the Faculty of Child and Adolescent Psychiatry). Melbourne: Royal Australian and New Zealand College of Psychiatrists.
WHO Commission on Social Determinants of Health. (2008). Closing the gap in a generation: Health equity through action on the social determinants of health. (Final Report of the WHO Commission on Social Determinants of Health). Geneva: World Health Organisation.
Women’s and Children’s Health Network, South Australia. (2014). Growth and development. Adelaide: Women’s and Children’s Health Network.
Zeanah Jr, C. H., & Zeanah, P. D. (2019). Infant mental health: The clinical science of early experience. In C. H. Zeanah Jr (Ed.), Handbook of infant mental health (4th ed., pp. 5–24). New York: The Guilford Press.
Zero to Three. (2001). Definition of infant mental health. Washington: National Center for Clinical Infant Programs.