The human violence that emerged after Hurricane Katrina as survivors desperately sought food and water will worsen the psychological debris left by the natural disaster itself, U.S. health experts warned on Thursday.

The struggle to stay alive is likely to trigger a rash of   stress-related issues that can lead to Depression and anxiety, especially among vulnerable children, experts said.

“Social order is just breaking down,” said psychologist Debra Borys, a disaster specialist who practices in Los Angeles. “To have the human-to-human violence added to the violence of nature - people could feel there is no safety.”

That   stress can add to the problems of coping with the aftermath of the storm itself, which wiped out much of the U.S. Gulf Coast, flooding Louisiana and Mississippi and displacing tens of thousands of people.

Scarce food and water has led to looting and arson fires. On Wednesday, a National Guard soldier was shot and wounded in New Orleans. Being tired, hungry and hot also makes the aftermath hard to deal with, experts said.

“When the resources run out they tend to have more difficulty in coping,” said Gerard Jacobs, a psychologist and head of the University of South Dakota’s Disaster Mental Health Institute.

Post-traumatic Stress Disorder is often associated with wartime combat, but it can strike after very stressful events such as natural disasters. People who survive are left shaken and can have flashbacks and nightmares.

Psychologists are most worried about children, especially those who have been separated from their families.

Parents struggling themselves to find shelter, food and other basic necessities may find it hard to explain the loss to their children.

Judith Myers-Walls, a child development and family studies professor at Purdue University in Indiana, said parents need to constantly talk to their children about the situation.

“It’s important that they realize parents don’t need to have all the answers,” she said. “By being honest, parents can show their kids how to cope with being afraid.”

While authorities are focusing on basic needs, experts said they should also bolster counseling and related services.

  stress and Anxiety can affect other diseases and trigger behavioral changes such as drug use, smoking and lethargy, according to federal health officials.

Signs of mental trouble may not show up for weeks or even months, but reports show refugees from Katrina are growing frustrated and angry.

As the death toll mounts, survivors must also cope with the sight of dead bodies and other gruesome images. Experts said survivors may be blocking out grief for now but that the loss will eventually hit them.

“I think that we will find people adjusting to the experience really for the rest of their lives,” Jacobs said.