Introduction

It is usual, when discussing animal development, to refer to the ‘life cycle’. In many ways this is appropriate. One could argue that human beings start from dependency and develop through to dependency again. However, the average human being also goes through periods of dependency throughout life, at times of weakness, illness and catastrophe. Furthermore, apart from the odd hermit, it could be said that the human condition is one of mutual dependency.

In another sense the perpetuation of the species is a ‘cycle’ of birth and death. In the following this notion is extended to consider a series of interlocking and interrelated life scripts or lines, which trace human development (Figure 2.1). These are punctuated by life events, some significant, some less significant depending on context, but at many of which doctors are present or involved. At each consultation the doctor sees only a snapshot of a person, family or community and their predicament. However, each predicament has its history and influences, which must be taken into account in determining, first, a formulation of the most prominent problem at that time, second, the most appropriate intervention, and, third, the likelihood of change in a wanted direction.

Figure 2.1 • The ‘chain-link’ net of interrelating and interlocking life cycles.

All psychiatric disorder occurs in a developmental context. There are characteristic life events, interactions with the lives of others and psychiatric disorders at each developmental stage. Some behaviours may be considered within the normal range at one age but as evidence of disorder at another (e.g. belief in Santa Claus would, in some Western cultures, be normal at age 4, but thought very strange at age 24). This example also illustrates the importance of context: if the 24-year-old was professing the belief in an infant school classroom, it would be less worrying than if it was reported in all seriousness in a consulting room (Figure 2.2).

Figure 2.2 • The occurrence of psychiatric disorders according to age.

That patterns of behaviour and interaction are repeated in successive generations has been frequently observed, and has led to theories and controversies about the relative contributions of nature and nurture. Clearly, this is only a question of focus of interest. It is not possible to be without a genetic inheritance, nor is it possible to avoid upbringing and environmental influences, and it is important to consider these different influences when determining the appropriateness and possibility of intervention. Genetics and environment continually interact, as, for example, when an individual genetically at increased risk of epilepsy has a seizure when hypoxic for some reason; or a woman with a strong family history of mood disorder becomes depressed when isolated looking after young children.

Since Descartes, Westerners have got used to considering the mind and body as separate entities. Macroscopically and microscopically this is spurious. All disorders – indeed all of life – have both psychological and physical components: even a fracture is determined by the psychological ‘set’ that led to the activity in which the fracture occurred, and the care that was taken over the activity. Similarly, the speed and circumstances of recovery and any subsequent disability may be determined as much by psychological as physical factors. Conversely, one cannot have a ‘thought’ without a corresponding parallel electrical and biochemical configuration in the brain. A multilevel developmental approach is illustrated schematically in Figure 2.3.

Figure 2.3 • The multilevel developmental approach.

Where to start?

Even before conception there are influences on an individual’s likely life script. ‘Assortative’ mating determines one’s parents, their respective genetic inheritances and life experiences. This concept suggests that there is not a random distribution of genes in society. One’s parents are usually joined by similar and/or complementary lifestyles, backgrounds, interests, levels of education, personalities and outlooks on life. Cultural considerations will determine how much, if at all, individuals may choose their own partner. Depending on the above, conception may have resulted from circumstances that range from a single encounter to a lengthy courting ritual followed by a careful choice of time, place and social setting.

Expectations of the pregnancy, birth, delivery and subsequent development, together with the degree to which these are fulfilled, can have a profound influence on the future of an individual. A 14-year-old who becomes pregnant after losing her virginity when drunk at a party has rather different expectations (and will experience different environmental pressures) from a 32-year-old professional woman, in a stable relationship for six years, who decides in consultation with her partner that ‘the time is right to start a family’.

Pregnancy may be marked by careful attention to preventing adverse influences on fetal development (‘good antenatal care’) or not (‘lacking in antenatal care’). This will in turn influence birthweight and the likelihood of perinatal complications. The presence or absence of such complications, apart from determining the risk of brain injury, will have an effect on the bonding of parent and child. A sick neonate may have reduced contact with its parents because of treatment, or indeed because of possible parallel sickness of the mother. Whether the child’s father is present can result from a number of factors, and his continued involvement will also affect the child’s future circumstances. An ill neonate is likely to present different responses from those presented by a healthy baby, being less responsive or more twitchy, for example. A twitchy baby may be disconcerting for parents, who may reduce their handling of the child and become more tense, thereby increasing the child’s jumpiness.

Studies of large cohorts of infants also show that there are wide variations, from birth, in the behaviour of individuals. The temperament of an infant, its ‘fit’ with the expectations of its parents and their capacity to manage the child may be crucial in determining a person’s future, or indeed their survival. Researchers in New York have shown a spectrum of infant temperaments ranging from ‘difficult’ to ‘easy’. A ‘difficult’ infant is not easy to cuddle, is irregular in its routines and cries frequently. In contrast, an ‘easy’ baby is regular in its routine, smiles frequently and is cuddly. An intermediate cluster of characteristics was labelled ‘slow to warm up’. Such infants appear ‘difficult’ at first, but after a little time come to resemble the ‘easy’ child.

Postnatal or puerperal depression occurs in 10–20% of women, depending on the criteria used. In some this will develop into a psychosis (see Chapter 12). The rapidity or otherwise with which this resolves will have an effect on the whole family, but in particular on the developing infant. It has been shown that there is poor coordination in the interactions between a depressed mother and her child, as though the ‘give and take’ is ‘out of step’. The infant becomes distressed and avoids interaction, which, in turn, affects the mother’s approaches, and their frequency and type. It has even been observed that maternal depression is associated with subsequent delays in the cognitive development of the infant. Also of later concern may be problems of attachment, although these may be mitigated by the availability of other carers.

‘Attachment’ is the quality of interaction between a child and its principal carer. It can be disrupted or altered by life events or disorders affecting the child, its carer or both. Clinical evidence suggests that quality of initial attachment is a template for future relationships. Also, the type of attachment experienced in early life will influence the speed and manner with which the various levels of independence are achieved. Both of these can influence the risk of developing a psychiatric disorder at a later stage in the life cycle (see Chapter 16).

In childhood the sorts of problems presenting to psychiatry are largely dictated by the stage of development and the expectations of the child’s carers. For example, most parents expect to be woken at night by a newborn infant, but they also expect the infant gradually to develop a sleep–wake cycle that resembles that of the rest of the family. If this does not occur and there are problems settling or night-time waking, then a sleep disorder may be presented (see Chapter 16). Similarly, when there are delays, abnormalities or excesses in behaviours at different stages of childhood, which cause suffering and/or handicap, then other child psychiatric disorders may be present.