All Our Sons: The Developmental Neurobiology and Neuroendocrinology of Boys at Risk

Abstract

Why are boys at risk? To address this question, I use the perspective of regulation theory to offer a model of the deeper psychoneurobiological mechanisms that underlie the vulnerability of the developing male. The central thesis of this work dictates that significant gender differences are seen between male and female social and emotional functions in the earliest stages of development, and that these result from not only differences in sex hormones and social experiences but also in rates of male and female brain maturation, specifically in the early developing right brain. I present interdisciplinary research which indicates that the stress-regulating circuits of the male brain mature more slowly than those of the female in the prenatal, perinatal, and postnatal critical periods, and that this differential structural maturation is reflected in normal gender differences in right-brain attachment functions. Due to this maturational delay, developing males also are more vulnerable over a longer period of time to stressors in the social environment (attachment trauma) and toxins in the physical environment (endocrine disruptors) that negatively impact right-brain development. In terms of differences in gender-related psychopathology, I describe the early developmental neuroendocrinological and neurobiological mechanisms that are involved in the increased vulnerability of males to autism, early onset schizophrenia, attention deficit hyperactivity disorder, and conduct disorders as well as the epigenetic mechanisms that can account for the recent widespread increase of these disorders in U.S. culture. I also offer a clinical formulation of early assessments of boys at risk, discuss the impact of early childcare on male psychopathogenesis, and end with a neurobiological model of optimal adult male socioemotional functions.Keywords: gender, right brain, testosterone, endocrine disruptors, attachment, early assessment, regulation theory, child psychiatry, pediatrics, brain development, neuroendocrinology RESUMEN: ¿Por están los niños varones bajo riesgo? Para responder esta pregunta he usado la perspectiva de la teoría de regulación con el fin de ofrecer un modelo de los más profundos mecanismos siconeurobiológicos que subyacen bajo la vulnerabilidad del varón en desarrollo. La tesis central de este trabajo indica que significativas diferencias de género se ven entre las funciones sociales y emocionales de varones y hembras en las más tempranas etapas del desarrollo, y que las mismas resultan no sólo de diferencias en las hormonas sexuales y experiencias sociales sino también en el ritmo de maduración cerebral de varones y hembras, específicamente en el temprano desarrollo del lado derecho del cerebro. Presento investigación interdisciplinaria que indica que los circuitos de regulación del estrés del cerebro del varón maduran más lentamente que los de la hembra en los períodos críticos prenatal, perinatal y posnatal, y que esta maduración estructural diferencial se refleja en diferencias de género normales e...

The early biopsychosocial development of boys and the origins of violence in males

“…This issue of the Infant Mental Health Journal follows several lines of research finding that a significant part of the origins of violence lies in the environment of prenatal to toddlerhood periods of development (Tremblay, ; Tremblay & Côté, this issue). In many ways, this focus on the very early periods of life reflects other examples of problematic outcomes such as childhood psychopathologies and school failure, also often found to have a basis in the first years of life (Caspi et al., ; Fearon & Belsky, ; Fitzgerald & Eiden, ; Hatzinikolaou & Murray, ; Lyons‐Ruth et al., ; Raine, this issue; Schore, ; Sroufe, ; Sroufe, Egeland, Carlson, & Collins, ). In addition, the articles in this special issue focus on another important line of research, which involves gender differences, concerning predilections for problematic behaviors related to sex‐specific neurobiological development, especially prevalent when children are raised under conditions of compromised caregiving (Golding & Fitzgerald , ; Holden, ; Kigar & Auger, ; Martel, ; McGinnis, Bockneck, Beeghly, Rosenblum, & Muzik, ; Schore, ; Zahn‐Waxler, Shirtcliff, & Marceau.…”

“…After birth, boys generally are considered to have slower developmental timetables (ZERO TO THREE, ), and this condition lasts well beyond adolescence. The World Health Organization () maintained that “Adolescent girls tend to reach biologically defined developmental milestones up to two years ahead of adolescent boys.” Schore () wrote about boys that “Due to this maturation delay, developing males also are more vulnerable over a longer period of time to stressors in the social environment (attachment trauma) and toxins in the physical environment (endocrine disruptors)” (p. 15).…”

“…Behaviorally, this greater susceptibility may manifest in an infant's reduced ability to self‐regulate when an attuned caregiver is not available to relate to the infant, as described in the preceding section on the self. Hence, “this longer period of developmental neurobiological immaturity is expressed in an oversensitivity to and inefficiency in regulating more intense and chronic forms of interpersonal stress” (Schore, , p. 27). Following his review of research on the fetal and neonatal developing male brain, Schore () concluded:

The slower maturation exposes the developing male brain to stressful altered levels of testosterone and corticosteroids during critical periods of right brain development.

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“…Hence, “this longer period of developmental neurobiological immaturity is expressed in an oversensitivity to and inefficiency in regulating more intense and chronic forms of interpersonal stress” (Schore, , p. 27). Following his review of research on the fetal and neonatal developing male brain, Schore () concluded:

The slower maturation exposes the developing male brain to stressful altered levels of testosterone and corticosteroids during critical periods of right brain development. Attachment trauma such as abuse and/or neglect interfere with or preclude optimal interactive stress regulation, and because they occur in critical periods of right brain development they epigenetically generate enduring maturational failures in the limbic system and the HPA, structural deficits that are re‐activated in adolescence, a time of substantial remodeling of cortical and limbic circuits.

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Mother–child verbal communication and preschoolers' inhibitory control

“…In this study, we explored the moderating role of child sex and verbal communication. With respect to child sex as a moderator, despite the male‐vulnerability claim that boys are more sensitive to both positive and negative environmental influences than girls, related findings do not uniformly support it (Schore, ). For example, although preschool boys are more sensitive than girls to the positive effect of parental sensitivity on sustained attention, preschool boys do not appear to be more sensitive to the positive effect of parental sensitivity on IC (Mileva‐Seitz et al, ).…”