Multilevel Dynamics in Developmental Psychopathology

Pathways to the Future: The Minnesota Symposia on Child Psychology, Volume 34

Ann S. Masten

• Publisher: Psychology Press
• Year: 2007
• ISBN:
  9781135594947
• Edition: 1
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

This latest volume in The Minnesota Symposia on Child Psychology Series highlights recent research across multiple levels of analysis to understand processes that shape development toward and away from behavioral problems and disorders over the life course, including the pathways to mental health.

Chapter 1
Gene–Environment Interplay and Developmental Psychopathology

Michael Rutter
Kings College, London

The general notion that genes might influence behavior has proved surprisingly controversial (Rutter, 2006a). Some of the concerns expressed have focused on methodological issues in relation to behavior genetics, some on the excessive claims of some genetic evangelists, some on a supposedly implied biological determinism, some on the problems in studying genetic influences on socially defined behaviors, and some on the negative messages about the possibility of making preventive or therapeutic interventions effective. However, many psychosocial researchers have been quite reluctant to accept the reality of genetic effects on individual differences, and some have seemed to want to place developmental psychology outside of both biology and medicine. This wish to separate off psychology is, however, based on a misunderstanding of what is entailed in a biomedical approach. Accordingly, it is necessary to outline some of the main biomedical principles before turning to the specifics of genetic concepts and findings. This is essential because any adequate understanding of the processes of normal and abnormal development must be based on these principles.

Biomedical Principles

In order to emphasize the close links between psychology and both biology and medicine, the principles are illustrated first by giving medical examples and then by turning to psychological ones.

Developmental Approaches Are Fundamental

It has long been recognized that any adequate understanding of the origins of disease must recognize the necessity of taking a developmental approach (Rutter & Sroufe, 2000). For example, the multiphase precancerous developments that precede the development of overt cancer constitute an essential element in the study of cancer. This is not just a matter of early diagnosis of tumors, but rather an appreciation that the development of cancer is preceded by changes that are benign in themselves but that predispose to a course of development that ultimately ends up with the growth of malignant tumors. A quite different example is provided by the evidence of the increased risk of heart disease in adult life that stems from impaired physical growth in the neonatal period (Barker, 1997, 1999; Bateson et al., 2004). The finding is of particular developmental interest because it is subnormal weight in infancy that predisposes to later heart disease, whereas in adult life, it is excessive weight that constitutes the risk factor. Herpes zoster, commonly known as shingles, constitutes a third, rather different, sort of example. This disease is due to a reactivation of the latent virus that will have caused chicken pox in childhood. Although shingles is most common in the elderly, its origins lie in the childhood infection of chicken pox.

Psychopathological examples are provided by schizophrenia, depression, and antisocial behavior. Schizophrenia used to be regarded as an adult-onset psychosis, but it is now clear that in a high proportion of cases it is a neurodevelopmental disorder that is first evident in childhood (Keshavan, Kennedy, & Murray, 2004). With respect to depression, it is important that prepubertal anxiety is a characteristic precursor of depression that begins only postpubertally (Eaves, Silberg, & Erklani, 2003). Life-course-persistent antisocial behavior, manifest in adulthood as antisocial personality dis order, typically begins in early childhood, usually in association with hyperactivity Moffitt, 1993; Moffitt, Caspi, Rutter, & Silva, 2001).

Many Disease Processes Are Dimensional

A second key biomedical principle is that many disease processes are dimensional in nature, with continuity between normality and pathology (Rutter, 2003). With respect to internal medicine, this is shown in the childhood origins of atheroma, the continuity in liability to allergies, and the continuity in liability to late-onset diabetes. There are clinically important transition points when the stage in the disease process is accompanied by an acute and pressing need for treatment, but the disease process itself is dimensional.

With respect to psychopathology, there are comparable continuities with respect to depression, antisocial behavior, and in the genetic liability to hyperactivity/inattention. Categorical distinctions are needed with respect to clinical decision making, but the psychopathological concept is clearly dimensional.

Many Risk Factors for Disease Are Dimensional

Most of the key risk factors for somatic disease are dimensional rather than categorical. Thus, for example, a raised cholesterol level, an increased clotting tendency of the blood, an increased blood pressure, and heavy smoking are all well-demonstrated risk factors for coronary artery disease. The same applies in the field of psychopathology. This is evident with respect to the intrauterine exposure to alcohol or smoking and the development of attention deficit disorder with hyperactivity (Linnet et al., 2003; Thapar et al., 2003). It is also evident in the consistent finding of an association between the number and severity of psychosocial risks and most types of mental disorder (Rutter, 2006b; Sameroff, 2006). Single risks, when experienced in isolation, tend to carry rather low risks but the cumulative effect of multiple risk factors is great.

There Are Multiple Causal Pathways to the Same Disease Endpoint

There are numerous examples of multiple causal pathways in internal medicine; one example illustrates the point (Rutter, 1997). Smoking, infections of the lung, and asthma all serve as pathways to obstructive lung disease. The initial phase in the causal pathway is quite different in each case—an irritant in the case of smoking, infection in the second pathway, and allergy in the third. With respect to psychopathology, ADHD may be used as an example in which prenatal alcohol exposure, prolonged institutional care in infancy, and neurodevelopmental impairment, all serve as causal pathways (Sandberg, 2002). The mechanisms at the beginning of the pathway are quite different, but the endpoints of different pathways look quite similar.

Risk Factors May Influence Several Different Outcomes

The converse also applies; that is to say, the same risk factor may influence the development of several quite different outcomes, although not necessarily through the same mechanism. Thus, smoking predisposes to lung cancer, coronary artery disease, osteoporosis, and wrinkling of the skin. In this case, we know that the causal mechanisms are quite different and the multiple endpoints arise because what is supposedly a single risk factor, namely smoking, actually encompasses a rather diverse range of risks including carcinogenic tars, carbon monoxide, and nicotinic effects on blood vessels. In the field of psychopathology, early parental loss has been shown to predispose to adult depression, alcoholism, and personality disorder (Maughan & McCarthy, 1997). In this case, we do not know whether the mechanisms for each of these outcomes is the same or different. However, it may be expected that, quite often, the mechanisms are disparate. For example, maltreatment in childhood is a risk factor for both antisocial behavior and for depressive disorders, but the evidence on gene—environment interactions suggests that the causal pathways are probably different (Caspi et al., 2002, 2003; Moffitt, Caspi, & Rutter, 2005).

Social Context Influences Risk

The evidence on social context effects is actually stronger in the field of internal medicine than it is in the field of mental disorders, although it is present for both (Rutter, 1999). Thus, there is much evidence that social inequality is a substantial risk factor for numerous diseases (Marmot & Wilkinson, 1999). The point here is that it is not the absolute level of affluence or poverty that matters, but rather the degree of inequality within the society in which the individual grows up. Similarly, there is substantial evidence that a lack of job autonomy is a pervasive risk factor for physical disease. The evidence suggests that it is not the work requirements of the job itself that matter, but rather the degree of control that the individual has over his work situation. In the field of psychopathology, the risk for anti social behavior associated with social disorganization in communities (Brooks-Gunn, Duncan, & Aber, 1997; Sampson, Raudenbush, & Earls, 1997) and the role of the school ethos (Rutter, Maughan, Mortimore, & Ouston with Smith, 1979; Rutter & Maughan, 2002) as a risk factor for childhood disorders constitute parallel examples.

Rejection of Dualism

It is clear from a large body of evidence that there is a two-way interplay between soma and psyche, and it makes no sense to regard one as in any sense more basic than the other. For example, it has been well demonstrated in both humans and animals that testosterone has significant effects on dominance but, equally, it has been shown that defeat in sporting combat leads to a drop in testosterone levels (Booth, Shelley, Mazur, Tharp, & Kittock, 1989; Mazur, Booth, & Dabbs, 1992). This is not a consequence of exercise because the effects are as evident with chess as they are with tennis. A rather different sort of example is provided by the effects of psychological treatments on brain imaging findings. The intervention is psychological but the effects are evident in brain functioning. Sometimes the effects of pharmacological treatments and psychological treatments are similar Baxter, Schwartz, Bergman, Szuba, Guze, et al., 1992) and sometimes they are different (Goldapple, Segal, Garson, Lau, Bieling, et al., 2004). A third example is provided by the effects of learning in adult life on brain structure—as shown, for example, by studies of London taxicab drivers and by studies of violin players (see Huttenlocher, 2002; Rutter, 2002). Elbert, Pantev, Wienbruch, Rockstroh, & Taub (1995), using magnetic resonance imaging (MRI), found that the cortical representation of the digits of the left hand in violinists and other string players was larger than that in controls and that the amount of cortical reorganization in the representation of the fingering digits was correlated with the age at which the person had begun to play. Maguire, Gadian, Johnsrude, Good, Ashburner, et al. (2000), also using structural MRI, found that the posterior hippocampi of London taxi drivers (who are required to gain an extensive knowledge of routes all over London—a process called gaining “the knowledge,” which usually takes place over 2 to 3 years) was significantly larger than that of controls. Hippocampal volume was correlated with the amount of time spent as a taxi driver. Both studies suggest that the brain has the capacity in later childhood or adult life to change in structure in response to environmental demands.

All workings of the mind have to be based on the functioning of the brain. That does not mean, of course, that the thought processes are caused by some neural feature, but it does mean that there has to be a neural accompaniment of any mental operation. A subdivision of mental disorders into those that are “medical” and those that are “social” is totally meaningless.

Identification of Physiological and Pathophysiological Pathways

A further biomedical principle is that there is a unifying concern to identify the physiological and pathophysiological pathways that are involved in any outcome that may be studied. This is so whether the starting point is an intrinsic or extrinsic risk factor. This is characteristic of the whole of medicine and biology, including psychopathology. For quite a while in psychology, there was a tendency to assume that it was somehow disloyal to the discipline to want to invoke physiology but, fortunately, that is now a thing of the past. It is crucially important to identify mental mechanisms, but it is equally important to determine the pathways involved and the physiological basis.

Rejection of Disproven Theories

A central feature of biomedical principles is the commitment to rejecting favored theories when the empirical data indicate that this is necessary. Thus, for a very long time peptic ulcer was thought to be due to stress, but it is now clear that it is actually the result of an infection. Much attention used to be paid to the effects of diet on cholesterol levels, but it came to be recognized that cholesterol levels were mainly influenced by liver...

Table of contents

• Cover
• Title
• Copyright
• Dedication
• Contents
• Preface
• 1 Gene—Environment Interplay and Developmental Psychopathology
• 2 Choreographing Genetic, Epigenetic, and Stochastic Steps in the Dances of Developmental Psychopathology
• 3 A Biology of Misfortune: Stress Reactivity, Social Context, and the Ontogeny of Psychopathology in Early Life
• 4 Understanding Developmental Processes of Resilience and Psychology: Implications for Policy and Practice
• 5 The Interior Life of the Family: Looking From the Inside Out and the Outside In
• 6 Peer Dynamics in the Development and Change of Child and Adolescent Problem Behavior
• 7 Depression in Youth: A Developmental Psychopathology Perspective
• 8 Toward the Application of a Multiple-Levels-of-Analysis Perspective to Research in Development and Psyehopathology
• 9 The Place of Development in Developmental Psychopathology
• Author Index
• Subject Index