Child and adolescent mental health

Why does children's mental health matter?

A child's emotional well-being is the single strongest predictor of adult life-satisfaction, greater than physical health, economic factors or educational level. Therefore, child mental health should be a key public health priority, and is fast becoming so.

Mental health disorders are common; since the 1960s there has been a fairly stable prevalence rate of around 10% in children under the age of 16 years. It is estimated that a further 10% have significant difficulties, yet are not clinically diagnosable. The rate rises to close to 40% in children and young people with co-existent physical health conditions. The risk is highest in young people with central nervous system disease. There are other known risk factors. Young people facing adverse life circumstances also have an increased prevalence of poorer physical and mental health. In the UK over the past 40 years, income inequality has spiralled, leaving an estimated 1 in 4 children living in relative poverty. Mental health conditions also represent the single biggest cause of morbidity in adults and half have symptom onset before the age of 15. Mental health is everyone's business and needs to be tackled at grass roots level.

To take one very stark example, let us consider eating disorders. Eating disorders are now more common in children than meningococcal disease; its peak incidence at age 15 is markedly greater than a number of chronic illnesses including type 1 diabetes. Around half of patients with anorexia nervosa who die will die of medical complications, and death rates in children in the UK are comparable with both asthma and diabetic ketoacidosis. Although it is a psychiatric diagnosis, the key medical aspects of care, especially those relating to being critically underweight, mean that they commonly present to paediatric services.

Why should paediatricians get involved in children's mental health?

Even with an optimally funded Child and Adolescent Mental Health Services (CAMHS) system, children with mental health problems will present to paediatricians. Some 40% of paediatric outpatient attendances involve an emotional or behavioural element, and if one turns to recurrent abdominal pain, the rate of significant mental health problems rises to around 80%.

In community paediatrics, the overlap with mental health is unavoidable, especially as safeguarding and the assessment of neurodevelopmental conditions such as attention deficit hyperactivity disorder (ADHD) are at the core of community work.

Cognitive development

Piaget proposed that cognitive development can be divided into phases, although we now recognize that these are not rigid and that the pace and patterns of cognitive development may vary significantly across children and cultural groups.

Below the age of two years, during the sensorimotor stage , infants' mental experiences are dominated by bodily sensations and a focus on their own actions as they begin to build up cognitive representations of an external world of objects. With the rapid acquisition of language during the preoperational stage , young children increasingly develop mental symbols to represent people, objects and actions in the physical world. Until 6–7 years, children's thinking is limited and they quite literally can only see things from their own cognitive viewpoint. With limited memory ability, they tend to focus on the here and now and will struggle to focus on more than one aspect of an event at any given time. Hence, children at this stage are egocentric and their intellect is characterized by attributing life-like qualities to inanimate objects, or imagining somewhat omnipotently that they can make something happen merely by thinking about it. They are overly swayed by how things appear and struggle to understand that invariant properties of objects (such as number, weight, mass and volume) remain unchanged even when the objects themselves are re­arranged in some way. Hence, this stage is dominated by the child's immediate perception of the world around them.

Between the ages of 6–7 and 11–12 years, the concrete operational stage , children are rapidly gaining an understanding of basic concepts about causality, time, space and matter as they develop the ability to hold several ideas in mind at the same time and carry out mental processes on the content. Of course, in modern cultures, intellectual growth is facilitated through statutory education by teachers who are trained in child development and by access to the worldwide web. Piaget proposed that the capacity to manipulate abstract, hypothetical and symbolic information was not reached until adolescence. This final formal operations stage is characterized by the ability to solve problems using scientific methodology and to think rationally and logically.

Social and moral development

We know that infants are born with innate neurological pre-wiring to engage in social relationships. They are equipped at birth to make eye contact, to follow another's gaze, to mimic human facial gestures, commonly sticking out their tongue, and later to engage in turn-taking, such as games of ‘peekaboo’.

The child's sense of self emerges from the way that other people react to them; we come to know ourselves through our interactions with others. For example, if a baby cries when a fun toy is withdrawn, a parent might respond by repeating the sequence, perhaps saying, ‘Let’s make that squeaky noise again’ and laughing with their child. Alternatively, if a baby looks alarmed and cries at the toy, a parent might quickly put it away and soothe her instead. Both actions demonstrate that the parent is able to function reflectively to hold their child in mind, sometimes referred to as ‘mind-mindedness’. The parent is also mirroring for the baby that she has been understood and that her feelings are meaningful to others.

Owning a sense of self is an important milestone for a child as this differentiates them from other people and confers a powerful sense of agency. In a classic experiment, it was shown that infants aged 18–24 months recognized themselves in a mirror. When a red spot was surreptitiously painted on their nose, at this age infants would see this in the mirror and touch it on their own faces, showing amusement or consternation. Younger infants do not respond in this way. Toddlers can begin to work out the intentions, feelings and beliefs of others so as to make sense of the social world around them. Psychologists often refer to this ability to understand the mental states of others as having ‘a theory of mind’, although, at least initially, children's empathic responses may be intuitive, rather than mediated by social cognition.

At around the same time as children develop a sense of self, they also demonstrate a capacity to infer what someone else is trying to do (i.e. their hidden intentions) and to use simple words to label their own mental states (the ‘I want’ and ‘No’ will be all too familiar to parents!). Over time, children develop a more sophisticated perspective, acquiring skills through interacting within their social environment, including playing with friends, and engaging with parents and siblings. By the time they reach 4 or 5 years of age, they are able to pass a classic ‘false belief test’, demonstrating the ability to take another's point of view when it is different from one's own. This can by demonstrated with the ‘Sally–Anne test’. In a nutshell, the child observes a doll, Sally, hiding a marble in a box before going out to play. Another doll, Anne, comes along, takes the marble, and places it elsewhere, say in a cupboard. Sally returns and the child is asked where she will now look for the marble. Younger children wrongly assume Sally will think the same as themselves and go to the new hiding place. From the perspective of understanding children's emotional and behavioural development, having a theory of mind equips them to anticipate and make judgements about how their own actions and feelings reciprocally impact on others.

We now know that there are a number of factors that both facilitate and inhibit social development and will impact on children's emotional and behavioural development. Having parents who struggle to tune into their child's emotional world, perhaps because they themselves had difficult childhoods or are experiencing mental health problems, or are living with harmful relationships characterized by domestic violence, delays social cognition. In extreme cases of neglect, such as observed in Romanian orphans, there is evidence of lifelong impairment in structural brain development. Structural changes are more subtle in those children living in the UK who have been abused or maltreated. Deficits in language and cognition, social and communication skills and emotional regulation persist.

Historically, philosophers and theologians have debated whether infants are born with original sin that requires eradicating through strict discipline, or resemble blank slates that are environmentally shaped, or whether childhood is rather more a romantic age of innocence. Research reveals something more interesting; that given a safe and secure environment, infants are instinctively prosocial but this basic capacity for kindness can be attenuated or even reversed by adverse life circumstances, including abusive parenting.

Infants as young as 10 months demonstrate clear preference for a victim character rather than an aggressor. By 15 months, toddlers will pick up an object dropped by an adult, seemingly with no expectation of a reward apart from the mere act of being helpful. At the same age, in experimental situations, children demonstrate a sense of fairness, anger against unfairness and evident surprise at unkind behaviour. However, it seems that good experiences of parenting and a safe environment are significant factors in nurturing these innate prosocial behaviours. Furthermore, the development of altruistic empathy is neurologically linked to the self-regulation of behaviours, including the ability to tolerate waiting for a reward. It seems that such a deceptively simple milestone paves the way to success in adulthood across diverse domains in life, including future employment and intimate relationships. In the 1970s, a famous study was designed to test a child's ability to delay gratification. Children aged 4–6 years were sat close to one delicious treat, such as a marshmallow, and told that if they waited for 15 minutes they could instead have two of them to eat. When these children were followed up as adults, those who were better able to delay gratification at a young age were relatively more successful. Competence in inhibiting behavioural impulses for strategic gain also depends on emotional maturity and self-regulation and develops in tandem with acquiring a theory of mind. This yoking of emotional and behavioural development is biologically mediated through shared executive brain mechanisms involving the prefrontal cortex. Conceptually, perhaps having a theory of mind allows one to imagine a future self as well as thinking about the mental state of others.

Genetic influences

A small but important minority of children with mental health problems have these as part of either a chromosomal trisomy or a single gene disorder. Even here, however, while some difficulties may stem directly from the conditions, others will result from, for example, frustration caused by other developmental problems.

For instance, there is an increased incidence of behavioural problems in Down's syndrome. The popular view of them as happy-go-lucky, cheerful souls conceals the significant behavioural difficulties encountered by many of them, combined with parental responses to coping with a vulnerable child, as shown in Box 24.1 .

Some of these difficulties may be inevitable, but for others there is potential for helpful early intervention. For instance, parents can be informed about the tendency of the children towards rigid behaviours, and take steps to help them cope, for example by early use of visual timetables, and careful preparation for transitions.

For most children with mental health difficulties, genetics exerts a ‘gravitational pull’, rather than determining the presence or absence of disorder. For instance, the heritability of ADHD is consistently estimated as around 80%, and yet the search for identifiable genetic changes to account for this figure has been largely fruitless. The same is proving to be true across child mental health.

Over and above the biological contribution of genetic information to final phenotype, environmental influences shape ongoing development. Some, but not all, of this influence is mediated by epigenetic mechanisms, but epigenetics is a mechanism, not a causative factor in its own right.

Environmental influences

Environmental influences can be classified by levels of description:

• Social/cultural

• Interpersonal

• Psychological

• Neurological

• Cellular

Take the example of domestic violence; clearly, this is a social phenomenon, and the normalization of violence against women plagues many cultures. Most research on the impact of violence focuses on the interpersonal, family level, via the effect on children of fear of one partner, and disorganized and confused responses to the other. However, the process also occurs at a neurological level, and we see evidence of effects on the limbic system. These brain level changes are in turn mediated by cellular changes, with neuro-endocrine influences to the fore – exposure to violence seems to be associated with chronic cortisol elevation, and cellular damage.

What social influences affect children's mental health?

We know that disruptive behaviour, and the diagnoses for which disruptive behaviour is a required feature, are more often reported in deprived socio-economic groups. There may be a genetic influence even here, as the traits that lead to disruptive behaviour are also maladaptive in education and employment, so parents possessing these traits may find themselves disadvantaged economically. On top of this, poverty robs the family of the resources, both financial and in terms of time, skills and emotional resilience, required to deal with disruption. Finally, deprived families have been found to have a more coercive parenting style, which is counterproductive (see Parenting , below).

The issue of electronic media is a current political and clinical hot topic, and the data quoted is likely to rapidly become out of date. There is an established link between more than 4 hours of weekday computer gaming (that is, after school) and low levels of well-being. However, it may be that unhappy children are escaping into gaming, as low levels of gaming are associated with higher levels of well-being than no gaming at all!

There does also appear to be a link between diagnosis of disruptive disorders (ADHD, autism spectrum disorder (ASD), conduct disorders) and diet, exercise and screen time. Again, this does not appear to be causal. Diet seems impossible to separate from broader socio-economic deprivation, as does exercise. Emerging evidence suggests that children with these disorders may seek out screen-based activities because these are easy to concentrate on, do not involve social failure or rejection, are perfectly structured and in many ways are highly predictable.

Substance misuse looms in adolescence, and appears to be both a consequence and cause of both poor subjective well-being and disruptive behaviour.

Sleep, both quality and quantity, is a vital support to emotional and behavioural resilience. Substance misuse, caffeine, use of screens late at night and anxiety can all impact on sleep, and can often be addressed with fairly simple interventions (see Further reading ).

Attachment

Attachment theory is an influential framework in psychology, which suggests the development of a set of expectations during the first few years, based on the child thinking of his/her carer as a ‘secure’ base from which to explore the world. This kind of security is extended in later life to include friends, partners and the person's own memories and feelings. Parents who attune to their child's emotional and physiological states, and respond so as to reduce discomfort and promote pleasant feelings, tend to foster children's attachment and security.

A very small number of children seem unable to form attachment relationships, even in the absence of other developmental problems; this condition, attachment disorder, appears to have a strong genetic basis. Other problems with attachment seem more likely to stem from a poor ‘match’ between infant cues and carer responses.

Carers who are unresponsive, unpredictable or frightening can lead to a disorganized pattern of attachment, where the child cannot settle on a single attachment strategy, and is, in turn, unpredictable. This pattern of attachment is associated with later psychopathology of all types across the lifespan.

Of less certain long-term significance is the distinction between secure and insecure attachment styles in the child. This categorization is based on observation of the strategies used by children when they are being parted from their carer. Around 40% of children show ‘insecure’ behaviours, stemming either from the overexpression or underexpression of their distress at separation. These responses should not be regarded as ‘abnormal’ and are better understood as commonly occurring adaptive strategies used by children to elicit optimal protective behaviour from their carers, who themselves might not be so finely attuned to the emotional needs of others. While this distinction may not be crucial in determining psychopathology, it can be a useful way to think about particular cases.

As well as providing a secure base via attachment processes, parents and carers provide the child with opportunities for exploration and play, and feedback on their efforts. This innocuous-sounding sentence conceals a wealth of complication. Take language, for example: the job of parents is to provide motivation for speech; that is, something to talk about. They must then ensure that the child's attempts at language are listened to, which means being, as far as possible, available to respond briefly. Responses should encourage further attempts at communication, so parents should be encouraging even if the answer to a specific enquiry is ‘no’. In conflict situations, parents need to encourage children to verbalize their feelings, as this will allow them to be processed and resolved. This is not the beginning of a parenting manual, but an example of how the very simple principles of good parenting play out in the complexity of everyday family life across domains of development.

The best data on children's subjective well-being was gathered in the 2013 NatCen study, Determinants of well-being , which surveyed a large cohort of seven-year-old children and their parents in the UK. It found that the most important determinants are social relationships. The children most likely to regard themselves as always happy were those who got on well with their siblings, had fun together with their family at weekends, and had lots of friends. They were also more likely not to bully others, and were less likely to be bullied themselves. Somewhat surprisingly, regular exercise was associated with, but did not predict, better well-being. Poor diet was not associated with worse well-being, but there seemed to be a link between very low levels of worry and consumption of junk food, seemingly suggesting that a little worry is actually good for us!

For adolescents, feeling supported and doing activities together, such as eating a meal, remain crucial, although the quality of peer relationships and lack of bullying become statistically significant.

Child abuse and neglect act at multiple levels to impact upon children's behaviour and well-being. The category is too broad to generalize the mechanisms, but attachment, self-image, nutrition and chronic stress all contribute. Of course, the child's own behaviour is an important determinant of their treatment by others, and so the causal influences are dynamic and reciprocal, not one-way.

Psychological characteristics

Children are not inert vessels into which we pour environmental influences. They have different temperaments, and the study of personality theory within psychology has identified many stable traits that vary between people. For children, individual differences in their emotional irritability, ease of temperament, locus of control, self-efficacy, novelty-seeking behaviour, self-esteem, anxiety and callous–unemotional traits, to name but a few, can influence feelings and behaviours. Again, the child's own individual make-up will reciprocally influence interactions with their physical and social environments, potentially shaping pathways to problems or success in life.

A key feature of humanity is our capacity for both introspection and agency; so thoughts, beliefs and attitudes about ourselves influence emotion and behaviour. For example, we know that optimism in a child is a powerful tool for emotional resilience, and that optimism is promoted by positive, specific adult comments, and parental responsiveness. Every clinical encounter provides an opportunity to promote this resilience, for example by asking about strengths, talents, abilities, achievements, hopes, aspirations and wishes.

This is described further in the section on emotional and behavioural development , above.

Neurological level

The brain is the arena upon which causal influences play out, and so the neurological findings (scan, EEG) associated with mental health problems are best thought of as a description, rather than ‘causes’ of mental dysfunction.

Much attention has recently been focused on discovering reliable imaging or EEG changes to aid the diagnosis and management of neurodevelopmental disorders. This has been a frustrating search, as one might expect, given that these are behaviourally defined syndromes, and the connection between brain structure and behaviour is unlikely to be straightforward. Nonetheless, some recent work has suggested a reproducible finding in ADHD of reduced dopamine receptor availability in the thalamus. However, this is not a structural change, but an alteration in the distribution of biochemistry within the brain. This linkage between structure and cellular processes is likely to be a fruitful area for further research.