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Mental Health in Children and Adolescents

Scientists and clinicians are pursuing the root causes of mental health struggles specific to young people to develop effective behavioral interventions.

Published June 1, 2003

By Vida Foubister
Academy Contributor

Image courtesy of stcom via stock.adobe.com.

Early childhood experiences appear to shape brain function in ways that confer either vulnerability or resilience to mental illness in children and adolescents. As scientists unravel the genetics and physiological mechanisms behind these changes in animals, clinicians are eager to translate their findings into new behavioral interventions. A recent Academy conference, to be the subject of a future Annals volume, explored how they can come together to do this.

Neonatal rats are programmed to form bonds with their mothers. During the first nine days of life, they develop a preference for their mother’s odor regardless of the quality of care that they receive, according to research done by Regina M. Sullivan, PhD, professor of Zoology at the University of Oklahoma.

She has shown that this learning, which enables nipple attachment and other activities necessary for survival, occurs in an experimental model whether the pups receive a “reward” of milk, a stroke or a shock after being exposed to an odor. And, given that about 12 of every 1,000 children are abused or neglected, she expects the same attachment pattern to be true in humans. “My working hypothesis is that the human child’s brain is wired to form an attachment whether the parent is being kind or not,” she said.

Sullivan’s data, though based on a rat model, could have other implications for research into the mental health of human children. There are physiological parallels between learning in human and rat infants. Thus the neural circuitry responsible for this attachment process, which involves the locus coeruleus in neonatal rats, might be shared.

Surprisingly Little Translational Research

While much of today’s medical knowledge is based on animal studies, there has been surprisingly little translational research in this area.

The March 2003 conference – Roots of Mental Illness in Children and Adolescents – at which Sullivan presented her findings was a first step toward filling this gap. The conference was organized by The New York Academy of Sciences (the Academy). It brought students of developmental neurobiology, developmental psychobiology and developmental psychopathology to New York City for two-and-a-half days of focused presentations and discussions.

According to Israel I. Lederhendler, PhD, director of the Behavioral and Systems Neuroscience Research Program at the National Institute of Mental Health and one of the conference organizers, the goal was “a little bit experimental and lots of fun.” Judging from the dialogue that resulted, it appears to have succeeded. The conference “strengthened the sense that there are important linkages that need to be explored and that the science is at the point where translational research is likely to lead to important breakthroughs,” said Megan R. Gunnar, PhD, Distinguished McKnight University Professor at the Institute of Child Development, University of Minnesota.

Attachment Disorders

Secure attachment between infants and their caregivers is known to be a protective factor and insecure attachment a risk factor for subsequent psychopathology. Charles H. Zeanah, Jr., MD, professor of Psychiatry and Pediatrics at Tulane University Health Sciences Center, has been studying one form of insecure attachment, called disorganized attachment, at an orphanage in Bucharest. “There’s a point at which attachment itself is reflective of a psychopathology, reactive attachment disorder, that’s defined in early childhood,” he said.

Zeanah has found the two patterns of this disorder, characterized either by emotional withdrawal or indiscriminate social extroversion, to be “readily identifiable” in these institutionalized children. Interestingly, however, a pilot project that aimed to reduce the number of caregivers for children in one unit of the institution dramatically reduced their signs of emotionally withdrawn reactive attachment disorder. “Secure attachment relationships appear to be protective in the context of high-risk environments,” he concluded.

Maternal separation in rats, where mothers are taken away from their offspring for three hours a day early in the first neonatal week, has been found to be associated with a transient decrease in hippocampal neurogenesis, reductions in hippocampal dendritic branching and a reduction in synaptic density. “This one fairly modest manipulation during the early part of these rats’ lives has profound long-term effects,” said Paul M. Plotsky, PhD, GlaxoSmithKline Professor of Psychiatry and Behavioral Sciences at Emory University School of Medicine. “There are a whole host of changes in the neurochemistry, behavioral profiles and morphology of these animals.”

Genetic Vulnerability

Nonetheless, only 33 to 45 percent of the animals in Plotsky’s study exhibit these effects in response to early maternal separation experiences. This suggests that some rats are genetically vulnerable to maternal separation and others are not. Studies done by Thomas R. Insel, director of the NIMH, in prairie voles underscore the importance of social experience in forming attachments.

Adult prairie voles form life-long partnerships, but only after mating triggers a release of dopamine in the nucleus accumbens. A D2 receptor agonist, which has no affect on mating behavior, eliminates partner preference in these animals. “The key then is that social attachment requires that social stimuli become linked to this major information stream in the forebrain,” said Insel.

Social behavior and physiology also appear to be linked in humans. Eye contact, for example, tenses middle ear muscles that enable the human voice to be distinguished from background noise. “If we extract from some of the animal and human work, we start realizing that some social behaviors are not learned behaviors but appear to be emergent properties of specific physiological states,” explained Stephen W. Porges, PhD, professor of Psychiatry at the University of Illinois at Chicago.

False Perceptions

Adult rhesus monkeys whose entire amygdala has been lesioned lose innate fear, such as that of snakes, but are able to function in social environments. However, when these monkeys are lesioned early in development, they show increased fear in social settings. There are very few people with amygdala lesions, but these findings are consistent with the behavior of one such female patient, “S.M.,” in her 30s. Though this woman appears to engage in normal social interactions, she is unable to detect fear in faces.

This interplay between fear and social motivation was further investigated in a recent study at the University of California, Davis. David G. Amaral, PhD, a professor of Psychiatry, found that amygdala-lesioned animals failed to demonstrate preference for their mothers over another female in a novel environment. Though this might appear to suggest failed maternal attachment, these monkeys didn’t seek out the comfort of their mothers, as they were unable to detect the novel environment as dangerous. “The amygdala may play some role in issues of impairment, such as in society anxiety,” Amaral concluded.

Bradley S. Peterson, MD, Suzanne Crosby Murphy Associate Professor in Pediatric Neuropsychiatry at Columbia University, is studying premature infants as a means to understand how disturbances in normal brain development might contribute to mental illnesses in children. A functional magnetic resonance imaging study of language processing found that they, unlike their full-term counterparts, tend to use phonological circuitry to process semantic material in their environment. “Preterm children may tend to hear semantic material, meaningful sounds and speech utterances, as meaningless junk,” he said.

Responding to Social Cues

Physically abused children studied by Seth D. Pollak, PhD, assistant professor in the Departments of Psychology and Psychiatry at the University of Wisconsin at Madison, also failed to respond appropriately to social cues in their environment. In this instance, however, the children were extremely sensitive to facial expressions of anger. They identified this emotion early in its formation and also detected it with little perceptual information from scrambled facial images.

“Their categories for anger are more inclusive,” explained Pollak. “A face that has maybe 30 percent anger in it but 70 percent sadness or fear is being interpreted as being an angry face. This really changes how children are interpreting social information that they’re receiving from the world.”

Though this heightened perception of anger might be beneficial in their home environments, it will likely cause them to misread cues in other social settings. “If we want to understand human development, especially with the goal of understanding the development of psychopathology, we need to bring together not only an understanding of the neuroscience of what is in children’s heads, but an understanding of what (environment) children’s heads are in,” Pollak concluded.

Also read: Using AI and Neuroscience to Transform Mental Health


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