Behavior genetics: past, present, future

Early childhood psychosocial family risks and cumulative dopaminergic sensitizing score: Links to behavior problems in U.S. 9-year-olds

BACKGROUND

We examined, (a) whether in early childhood exposure to risky family environment in different domains (socioeconomic, mental, parenting practices, health behavior, and child-related risks) and accumulatively across various domains (cumulative risk) is associated with child's problem behavior at age 9, and (b) whether the association is more pronounced in children carrying cumulative dopaminergic sensitizing genotype or living in low-income families.

METHODS

Participants were 2,860 9-year old children (48% females; 48% Black) and their mothers from the 'Fragile Families and Child Wellbeing Study', a probability birth cohort from large U.S. cities. Mothers responded to questions on child's problem behavior (CBCL). Children responded to questions about their vandalism and substance use.

RESULTS

Cumulative family risk was associated with higher internalizing and externalizing behavior and higher vandalism and substance use. All domain-specific risk clusters were associated with higher internalizing behavior and, with the exception of child-related risk, with higher externalizing behavior. Mental health risks, risky parenting practices, and risky health behavior were associated with higher vandalism. Risky parenting practices were associated with higher substance use. The associations were robust to adjustment for cumulative dopaminergic sensitizing genotype. No G x E interactions with dopaminergic genotype and family SES were observed.

LIMITATIONS

Sample size was relatively small for genetic analysis and polygenic risk scores were not available.

CONCLUSIONS

Exposure to cumulative psychosocial family risks from early childhood is associated with early indicators of problem behavior in adolescence.

Long-term Cognitive, Psychological, and Health Outcomes Associated With Child Abuse and Neglect

Potential long-lasting adverse effects of child maltreatment have been widely reported, although little is known about the distinctive long-term impact of differing types of maltreatment. Our objective for this special article is to integrate findings from the Mater-University of Queensland Study of Pregnancy, a longitudinal prenatal cohort study spanning 2 decades. We compare and contrast the associations of specific types of maltreatment with long-term cognitive, psychological, addiction, sexual health, and physical health outcomes assessed in up to 5200 offspring at 14 and/or 21 years of age. Overall, psychological maltreatment (emotional abuse and/or neglect) was associated with the greatest number of adverse outcomes in almost all areas of assessment. Sexual abuse was associated with early sexual debut and youth pregnancy, attention problems, posttraumatic stress disorder symptoms, and depression, although associations were not specific for sexual abuse. Physical abuse was associated with externalizing behavior problems, delinquency, and drug abuse. Neglect, but not emotional abuse, was associated with having multiple sexual partners, cannabis abuse and/or dependence, and experiencing visual hallucinations. Emotional abuse, but not neglect, revealed increased odds for psychosis, injecting-drug use, experiencing harassment later in life, pregnancy miscarriage, and reporting asthma symptoms. Significant cognitive delays and educational failure were seen for both abuse and neglect during adolescence and adulthood. In conclusion, child maltreatment, particularly emotional abuse and neglect, is associated with a wide range of long-term adverse health and developmental outcomes. A renewed focus on prevention and early intervention strategies, especially related to psychological maltreatment, will be required to address these challenges in the future.

Ongoing Pediatric Health Care for the Child Who Has Been Maltreated

Pediatricians provide continuous medical care and anticipatory guidance for children who have been reported to state child protection agencies, including tribal child protection agencies, because of suspected child maltreatment. Because families may continue their relationships with their pediatricians after these reports, these primary care providers are in a unique position to recognize and manage the physical, developmental, academic, and emotional consequences of maltreatment and exposure to childhood adversity. Substantial information is available to optimize follow-up medical care of maltreated children. This new clinical report will provide guidance to pediatricians about how they can best oversee and foster the optimal physical health, growth, and development of children who have been maltreated and remain in the care of their biological family or are returned to their care by Child Protective Services agencies. The report describes the pediatrician's role in helping to strengthen families' and caregivers' capabilities and competencies and in promoting and maximizing high-quality services for their families in their community. Pediatricians should refer to other reports and policies from the American Academy of Pediatrics for more information about the emotional and behavioral consequences of child maltreatment and the treatment of these consequences.

Applying a Lifespan Developmental Perspective to Chronic Pain: Pediatrics to Geriatrics

An ideal taxonomy of chronic pain would be applicable to people of all ages. Developmental sciences focus on lifespan developmental approaches, and view the trajectory of processes in the life course from birth to death. In this article we provide a review of lifespan developmental models, describe normal developmental processes that affect pain processing, and identify deviations from those processes that lead to stable individual differences of clinical interest, specifically the development of chronic pain syndromes. The goals of this review were 1) to unify what are currently separate purviews of "pediatric pain," "adult pain," and "geriatric pain," and 2) to generate models so that specific elements of the chronic pain taxonomy might include important developmental considerations.

PERSPECTIVE

A lifespan developmental model is applied to the forthcoming Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks-American Pain Society Pain Taxonomy to ascertain the degree to which general "adult" descriptions apply to pediatric and geriatric populations, or if age- or development-related considerations need to be invoked.

Aetiological influences on stability and change in emotional and behavioural problems across development: a systematic review

Emotional and behavioural problems in childhood and adolescence can be chronic and are predictive of future psychiatric problems. Understanding what factors drive the development and maintenance of these problems is therefore crucial. Longitudinal behavioural genetic studies using twin, sibling or adoption data can be used to explore the developmental aetiology of stability and change in childhood and adolescent psychopathology. We present a systematic review of longitudinal, behavioural genetic analyses of emotional and behavioural problems between ages 0 to 18 years. We identified 58 studies, of which 19 examined emotional problems, 30 examined behavioural problems, and 9 examined both. In the majority of studies, stability in emotional and behavioural problems was primarily genetically influenced. Stable environmental factors were also widely found, although these typically played a smaller role. Both genetic and environmental factors were involved in change across development. We discuss the findings in the context of the wider developmental literature and make recommendations for future research.

Widowhood and the Stability of Late Life Depressive Symptomatology in the Swedish Adoption Twin Study of Aging

Although the Swedish Adoption Twin of Aging (SATSA) has been used to investigate phenotypic stability of late life depressive symptoms, the biometric processes underlying this stability have not been studied. Under a reciprocal effects modeling framework, we used SATSA twins' Center for Epidemiologic Studies Depression (CES-D) Scale data across 5 waves (from 1987-2007) to test whether the reciprocal exchange between twins within a family and their nonshared environments (P<=>E) promote the accumulation of gene-environment correlation (rGE) over time. The model generates increasing rGE that produces subsequent stable environmental differences between twins within a family-a process hypothesized to explain stability in chronic late life depressive symptoms. Widowhood is included as a stressful life experience that may introduce an additional nonshared source of variability in CES-D scores. Genetic effects and nonshared environmental effects are primary sources of stability of late life depressive symptoms without evidence of underlying rGE processes. Additionally, widowhood explained stable differences in CES-D scores between twins within a family up to 3 years after spousal loss.

Underlying Mechanisms of Gene-Environment Interactions in Externalizing Behavior: A Systematic Review and Search for Theoretical Mechanisms

Over the last decade, several candidate genes (i.e., MAOA, DRD4, DRD2, DAT1, 5-HTTLPR, and COMT) have been extensively studied as potential moderators of the detrimental effects of postnatal family adversity on child externalizing behaviors, such as aggression and conduct disorder. Many studies on such candidate gene by environment interactions (i.e., cG × E) have been published, and the first part of this paper offers a systematic review and integration of their findings (n = 53). The overview shows a set of heterogeneous findings. However, because of large differences between studies in terms of sample composition, conceptualizations, and power, it is difficult to determine if different findings indeed illustrate inconsistent cG × E findings or if findings are simply incomparable. In the second part of the paper, therefore, we argue that one way to help resolve this problem is the development of theory-driven a priori hypotheses on which biopsychosocial mechanisms might underlie cG × E. Such a theoretically based approach can help us specify our research strategies, create more comparable findings, and help us interpret different findings between studies. In accordance, we describe three possible explanatory mechanisms, based on extant literature on the concepts of (1) emotional reactivity, (2) reward sensitivity, and (3) punishment sensitivity. For each mechanism, we discuss the link between the putative mechanism and externalizing behaviors, the genetic polymorphism, and family adversity. Possible research strategies to test these mechanisms, and implications for interventions, are discussed.

Birth Weight and Adult IQ, but Not Anxious-Depressive Psychopathology, Are Associated with Cortical Surface Area: A Study in Twins

Background

Previous research suggests that low birth weight (BW) induces reduced brain cortical surface area (SA) which would persist until at least early adulthood. Moreover, low BW has been linked to psychiatric disorders such as depression and psychological distress, and to altered neurocognitive profiles.

Aims

We present novel findings obtained by analysing high-resolution structural MRI scans of 48 twins; specifically, we aimed: i) to test the BW-SA association in a middle-aged adult sample; and ii) to assess whether either depression/anxiety disorders or intellectual quotient (IQ) influence the BW-SA link, using a monozygotic (MZ) twin design to separate environmental and genetic effects.

Results

Both lower BW and decreased IQ were associated with smaller total and regional cortical SA in adulthood. Within a twin pair, lower BW was related to smaller total cortical and regional SA. In contrast, MZ twin differences in SA were not related to differences in either IQ or depression/anxiety disorders.

Conclusion

The present study supports findings indicating that i) BW has a long-lasting effect on cortical SA, where some familial and environmental influences alter both foetal growth and brain morphology; ii) uniquely environmental factors affecting BW also alter SA; iii) higher IQ correlates with larger SA; and iv) these effects are not modified by internalizing psychopathology.