An innovative program run by Children’s Hospital of Los Angeles is trying to head off mental health issues in older children by improving their home lives when they're babies and toddlers. 

Through its "early childhood mental health program," the hospital sends therapists into the homes of  hundreds of kids who are showing signs of anxiety, trauma and stress that can pile up causing what experts call "toxic stress."

Similar to nurse home-visiting programs that the White House is trying to expand, counselors in this program teach parents how to diffuse stress in the home and to understand and meet their children’s emotional needs. About 400 families are served every year.

Among them are Shantoya Byrd and her toddler, Anmarie Paz.

When Anmarie was just weeks old, her aunt committed suicide in the home they shared.

“I was so, so, sad,” Byrd said. “And then you feel really bad because you’re like, now I have a baby, and the baby sees you so sad.”

Byrd was also living with her mother, who was struggling with drug addiction. When Anmarie was six months old, social workers found the home unfit and removed her. She was reunited with her mother a few days later, when Byrd moved out on her own.

“When I got her back, I couldn’t walk to the kitchen without her like following behind me screaming," she said. "If she could not like touch me, she would scream, she would cry.”

Anmarie was suffering from severe anxiety. She cried and yelled nonstop. Byrd didn't understand why or how to deal with it.

Experts said the kinds of stressors that Anmarie was experiencing compound for a baby. If left untreated, they could cause permanent damage. Anmarie falls squarely into a newer field of research in neuroscience that examines toxic stress and brain development.

“Because the brain is changing so rapidly so early, the influence of those experiences can be very powerful early, and it takes more to change things later on,” said USC neuroscientist Pat Levitt.

He is a proponent of early intervention for babies living in toxic stress environments, like the one Children's Hospital uses.

Child welfare workers referred Byrd to the program, which sent psychotherapist Lorena Samora to her Los Angeles apartment.

During weekly visits, Samora was able to coach the young mother on techniques for helping her toddler to self-soothe and lessen anxiety.

One year later, Byrd talks to Anmarie, now 20-months-old, a lot, routinely explaining why she is leaving or that she will be back soon and that she loves her. Anmarie is much calmer.

It’s a technique that Levitt calls “serve and return” and he says it's critical to a developing child's brain.

Program director Marian Williams said a family that requires one year of in-home, weekly visits, plus occupational therapy and other services can cost about $50,000 per family. Just a weekly visit from a therapist can run up to $20,000 per year. It's funded through a contract through with the Los Angeles County Department of Mental Health.

“It would be important to contrast that [program] cost with the cost of not providing services,” she said.

Children who don't get the understanding and support they need at home become harder and harder for the parents to handle, Williams said. They might end up in foster care or suffer from significant mental health issues later.

The program has been around for a decade. Not every case goes as well as Byrd's.

Williams said each family has its own personal goals - but for some families "barriers are so great that they have trouble focusing on their children."

Should you worry about toxic stress?

From an FAQ created by the Harvard Center on the Developing Child, which studies the impact of toxic stress on small children, among other areas.

Q: When should we worry about toxic stress?

A: If at least one parent or caregiver is consistently engaged in a caring, supportive relationship with a young child, most stress responses will be positive or tolerable. For example, there is no evidence that, in a secure and stable home, allowing an infant to cry for 20 to 30 minutes while learning to sleep through the night will elicit a toxic stress response. However, there is ample evidence that chaotic or unstable circumstances, such as placing children in a succession of foster homes or displacement due to economic instability or a natural disaster, can result in a sustained, extreme activation of the stress response system. Stable, loving relationships can buffer against harmful effects by restoring stress response systems to “steady state.” When the stressors are severe and long-lasting and adult relationships are unresponsive or inconsistent, it’s important for families, friends, and communities to intervene with support, services, and programs that address the source of the stress and the lack of stabilizing relationships in order to protect the child from their damaging effects.

Q: What can we do to prevent damage from toxic stress response?

A: The most effective prevention is to reduce exposure of young children to extremely stressful conditions, such as recurrent abuse, chronic neglect, caregiver mental illness or substance abuse, and/or violence or repeated conflict. Programs or services can remediate the conditions or provide stable, buffering relationships with adult caregivers. Research shows that, even under stressful conditions, supportive, responsive relationships with caring adults as early in life as possible can prevent or reverse the damaging effects of toxic stress response. 

VIDEO: When should I be worried about my child? What is Toxic Stress for a infant?

VIDEO: How can a parent build healthy emotional and cognitive skills in infants?

Correction: This story misstated neuroscientist Pat Levitt's affiliation. He is a researcher at USC, not UCLA. KPCC regrets the error.