So far in this course we have dealt entirely with the evolution of characters that are controlled by simple Mendelian inheritance at a single locus. There are notes on the course website about gametic disequilibrium and how allele frequencies change at two loci simultaneously, but we didn’t discuss them. In every example we’ve considered we’ve imagined that we could understand something about evolution by examining the evolution of a single gene. That’s the domain of classical population genetics. For the next few weeks we’re going to be exploring a field that’s actually older than classical population genetics, although the approach we’ll be taking to it involves the use of population genetic machinery. If you know a little about the history of evolutionary biology, you may know that after the rediscovery of Mendel’s work in 1900 there was a heated debate between the “biometricians” (e.g., Galton and Pearson) and the “Mendelians” (e.g., de Vries, Correns, Bateson, and Morgan). Biometricians asserted that the really important variation in evolution didn’t follow Mendelian rules. Height, weight, skin color, and similar traits seemed to

Human biochemical genetics

This chapter suggests that delinquency conceals two distinct categories of individuals, each with a unique natural history and etiology: A small group engages in antisocial behavior of one sort or another at every life stage, whereas a larger group is antisocial only during adolescence. According to the theory of life-course-persistent antisocial behavior, children's neuropsychological problems interact cumulatively with their criminogenic environments across development, culminating m a pathological personality. According to the theory of adolescence-limited antisocial behavior, a contemporary maturity gap encourages teens to mimic antisocial behavior in ways that are normative and adjustive. There are marked individual differences in the stability of antisocial behavior. The chapter reviews the mysterious relationship between age and antisocial behavior. Some youths who refrain from antisocial behavior may, for some reason, not sense the maturity gap and therefore lack the hypothesized motivation for experimenting with crime.

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Adolescence-limited and life-course-persistent antisocial behavior: A developmental taxonomy.

Attachment--and loss.

The concept of mechanisms that protect people against the psychological risks associated with adversity is discussed in relation to four main processes: reduction of risk impact, reduction of negative chain reactions, establishment and maintenance of self-esteem and self-efficacy, and opening up of opportunities. The mechanisms operating at key turning points in people's lives must be given special attention.

Psychosocial Resilience and Protective Mechanisms

How we raise young children is one of today's most highly personalized and sharply politicized issues, in part because each of us can claim some level of "expertise." The debate has intensified as discoveries about our development-in the womb and in the first months and years-have reached the popular media. How can we use our burgeoning knowledge to assure the well-being of all young children, for their own sake as well as for the sake of our nation? Drawing from new findings, this book presents important conclusions about nature-versus-nurture, the impact of being born into a working family, the effect of politics on programs for children, the costs and benefits of intervention, and other issues. The committee issues a series of challenges to decision makers regarding the quality of child care, issues of racial and ethnic diversity, the integration of children's cognitive and emotional development, and more. Authoritative yet accessible, From Neurons to Neighborhoods presents the evidence about "brain wiring" and how kids learn to speak, think, and regulate their behavior. It examines the effect of the climate-family, child care, community-within which the child grows.

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From Neurons to Neighborhoods: The Science of Early Childhood Development

Objectives: To compare the cumulative costs of public services used through to adulthood by individuals with three levels of antisocial behaviour in childhood. Design: Costs applied to data of 10 year old children from the inner London longitudinal study selectively followed up to adulthood. Setting: Inner London borough. Participants: 142 individuals divided into three groups in childhood: no problems, conduct problems, and conduct disorder. Main outcome measures: Costs in 1998 prices for public services (excluding private, voluntary agency, indirect, and personal costs) used over and above basic universal provision. Results: By age 28, costs for individuals with conduct disorder were 10.0 times higher than for those with no problems (95% confidence interval of bootstrap ratio 3.6 to 20.9) and 3.5 times higher than for those with conduct problems (1.7 to 6.2). Mean individual total costs were £70 019 for the conduct disorder group (bootstrap mean difference from no problem group £62 898; £22 692 to £117 896) and £24 324 (£16 707; £6594 to £28 149) for the conduct problem group, compared with £7423 for the no problem group. In all groups crime incurred the greatest cost, followed by extra educational provision, foster and residential care, and state benefits; health costs were smaller. Parental social class had a relatively small effect on antisocial behaviour, and although substantial independent contributions came from being male, having a low reading age, and attending more than two primary schools, conduct disorder still predicted the greatest cost. Conclusions: Antisocial behaviour in childhood is a major predictor of how much an individual will cost society. The cost is large and falls on many agencies, yet few agencies contribute to prevention, which could be cost effective. What is already known on this topic Children who show substantial antisocial behaviour have poor social functioning as adults and are at high risk of social exclusion Costs are available for particular items of public service such as receiving remedial education or appearing in court What this study adds Costs of antisocial behaviour incurred by individuals from childhood to adulthood were 10 times greater for those who were seriously antisocial in childhood than for those who were not The costs fell on a wide range of agencies Reduction of antisocial behaviour in childhood could result in large cost savings

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Financial cost of social exclusion: follow up study of antisocial children into adulthood.

The possible mechanisms involved in continuities and discontinuities in psychopathology between childhood and adult life are considered in relation to the findings from systematic, prospective, long-term longitudinal studies. Findings on schizophrenia, neurodevelopmental disorders, emotional disturbances, antisocial behaviour and substance abuse are used as conditions illustrating the key issues. The overarching themes are then discussed in relation to heterotypic continuity and psychopathologic progression, early age at onset and a range of possible mediating mechanisms - including genetic mediation, 'kindling' effects, environmental influences, coping mechanisms and cognitive processing of experiences. Some of the key research challenges that remain concern the testing of competing hypotheses on mediating processes, the changes involved in adolescence, the transition from prodromal phase to overt schizophrenia and the emergence of adolescent-limited antisocial behaviour. Greater use needs to be made of genetic research strategies and of the testing of possible cognitive processing mediation effects.

Continuities and discontinuities in psychopathology between childhood and adult life.

Background: Despite an expanding epidemiological evidence base, uncertainties remain over key aspects of the epidemiology of the ‘antisocial’ disorders in childhood and adolescence.

Methods:  We used cross-sectional data on a nationally representative sample of 10,438 5–15-year-olds drawn from the 1999 British Child Mental Health Survey to examine age trends, gender ratios and patterns of comorbidity in DSM-IV Conduct Disorder (CD) and Oppositional Defiant Disorder (ODD).

Results:  CD was significantly more common in boys than girls, and increased in prevalence with age. Among children who met diagnostic criteria for CD, status violations and other non-aggressive conduct problems increased with age, while aggressive symptoms became less common. Gender differences in ODD varied by reporter. Estimates of age trends in ODD depended heavily on treatment of overlaps with CD. Following DSM-IV guidelines (where ODD is not diagnosed in the presence of CD), rates of ODD fell with age; if that constraint was released, clinically significant rates of oppositionality persisted at similar levels from early childhood to middle adolescence. CD and ODD showed high levels of overlap, and both diagnoses showed substantial comorbidity with other non-antisocial disorders.

Conclusions:  Results from this large-scale study confirm and extend previous findings in the epidemiology of the disruptive behaviour disorders.

Conduct Disorder and Oppositional Defiant Disorder in a national sample: developmental epidemiology

Resilience to adult psychopathology following childhood maltreatment: Evidence from a community sample

BACKGROUND: 
Existing evidence points to a substantial rise in psychosocial disorders affecting young people over the past 50 years (Rutter & Smith, 1995). However, there are major methodological challenges in providing conclusive answers about secular changes in disorder. Comparisons of rates of disorder at different time points are often affected by changes in diagnostic criteria, differences in assessment methods, and changes in official reporting practices. Few studies have examined this issue using the same instruments at each time point.

METHODS: 
The current study assessed the extent to which conduct, hyperactive and emotional problems have become more common over a 25-year period in three general population samples of UK adolescents. The samples used in this study were the adolescent sweeps of the National Child Development Study and the 1970 Birth Cohort Study, and the 1999 British Child and Adolescent Mental Health Survey. Comparable questionnaires were completed by parents of 15-16-year-olds at each time point (1974, 1986, and 1999).

RESULTS AND CONCLUSIONS: 
Results showed a substantial increase in adolescent conduct problems over the 25-year study period that has affected males and females, all social classes and all family types. There was also evidence for a recent rise in emotional problems, but mixed evidence in relation to rates of hyperactive behaviour. Further analyses using longitudinal data from the first two cohorts showed that long-term outcomes for adolescents with conduct problems were closely similar. This provided evidence that observed trends were unaffected by possible changes in reporting thresholds.

Barbara Maughan

Papers

Financial cost of social exclusion: follow up study of antisocial children into adulthood.

Continuities and discontinuities in psychopathology between childhood and adult life.

Conduct Disorder and Oppositional Defiant Disorder in a national sample: developmental epidemiology

Resilience to adult psychopathology following childhood maltreatment: Evidence from a community sample

Time trends in adolescent mental health.