Traumatic experiences can have a big impact on a person’s mental health. Multiple traumas can have even more severe effects.

Since the middle of August, natural disasters have struck multiple times in Mexico, the Caribbean, and the southeastern United States.

Each new hurricane or earthquake has only added to the devastation in these areas as well as to the damage done to residents’ mental health.

On Saturday, two more earthquakes hit southern Mexico, following on the heels of the more violent quakes that shook the region earlier this month.

Starting in August, Hurricanes Harvey and Irma tore a path of destruction across the Caribbean and southeastern United States, with Hurricane Maria hammering Puerto Rico this past week.

Experts say that the potential for post-traumatic stress-disorder (PTSD) is quite real after disasters like this, with an even higher risk after multiple traumas.

PTSD is a mental health problem that some people develop after experiencing a violent or life-threatening event, such as military combat, a car accident, sexual assault, and even natural disasters.

“There is definitely a lot of PTSD that is developed after natural disasters, especially with ones of the magnitude we’re seeing recently with all of these hurricanes and earthquakes,” Dr. Amit Etkin, an associate professor of psychiatry and behavioral sciences at Stanford University, told Healthline.

Symptoms of PTSD include being unable to relax for fear that the trauma will return, or avoiding places or situations that remind you of the trauma. People may also relive the trauma in flashbacks or nightmares.

The U.S. Department of Veterans Affairs estimates that 7 to 8 percent of Americans will have PTSD at some point in their lives.

However, Etkin said that “most people actually do respond fine and are resilient after a trauma.”

Some research has found that up to 92 percent of adults and 95 percent of children develop PTSD after an earthquake.

Etkin said that several factors determine how people respond to a trauma, including how long the trauma lasted, whether it was a single or multiple events, a person’s age when it happened, and the nature of the threat.

For example, the strength of a hurricane or earthquake can affect a person’s response to it, as can how close they were to the quake’s epicenter or the hurricane’s path.

Experiencing multiple traumas — whether it’s two earthquakes in the span of one month or multiple tours of duty in a combat zone — not only increases your risk of developing PTSD, but also can change the nature of your symptoms.

“People with single-trauma PTSD tend to have more anxiety, startle more, and are a bit more hyperactive,” said Etkin. “But people who have had multiple traumas tend to be more depressed and blunted in their response.”

Etkin added that single-trauma and multiple-trauma PTSD can look very different from each other — and from healthy people — but these conditions still fall under the “same umbrella of PTSD.”

Cancer is another type of trauma that can lead to PTSD.

One study found that more than one-third of non-Hodgkin’s lymphoma survivors still had PTSD symptoms more than seven years after diagnosis.

For many survivors, fear that the cancer will return hangs like a dark cloud over their daily lives.

When Jamie Reno’s cancer recurred a second time, three years after his first diagnosis at age 35 with stage 4 non-Hodgkin’s lymphoma, he “lost it” and ended up at the hospital in the emergency department.

“I had a panic attack,” Reno told Healthline. “I just freaked out. I said, ‘Oh my God, it’s not happening again.’”

This kind of response to a cancer diagnosis — especially a second one — isn’t unusual for many people, along with other reactions such as sadness, worry, trouble sleeping, or feeling uncertain about the future.

But it doesn’t necessarily mean that they have PTSD.

After the panic attack, the emergency room doctors put Reno on a benzodiazepine for anxiety — which he called a “horrible, evil drug” because it was so hard to get off it.

He also saw a psychologist for a while, but he stopped going when he realized that he was getting through this on his own — along with the help of his “angel of a wife,” other family, and friends.

“That second time I didn’t want to deal with it,” said Reno. “I just wanted to walk away. But I finally decided that you can’t walk away from what’s going on in your body because when you walk away, it comes with you.”

Reno, an award-winning journalist and singer-songwriter-guitarist, is now in his fourth battle with cancer. He has tumors in his abdomen, which at the moment aren’t growing — putting him in a “watch and wait” phase.

Because of the “horrible daily pain” from the tumors, Reno only sleeps about two or three hours a night.

The pain isn’t the only thing keeping him awake at night.

“It’s also the fear and anxiety that at any time this cancer could grow again,” said Reno. “But I just don’t dwell on it. I’ve got a great family, a great career, great friends, and a great life here in San Diego.”

Reno’s book, “Hope Begins in the Dark,” chronicles the stories of 40 lymphoma survivors, many of whom have also gone through cancer several times.

The most recommended treatment for PTSD is trauma-focused psychotherapy.

The Veterans Affairs agency lists several types that have strong scientific evidence to back them up, including prolonged exposure, cognitive processing therapy, and eye-movement desensitization and reprocessing.

These treatments help people process a traumatic experience through talking, visualizing, or thinking about the trauma.

Medications for depression and anxiety — such as Zoloft, Paxil, and Prozac — are also sometimes used.

However, Etkin said that the “effectiveness of medications for PTSD is very questionable.”

In theory, psychotherapy may also better prepare people to respond to future traumas compared to medications.

“Typically, after you stop taking the medication, its effects go away, in terms of the adaptations it’s making on the brain,” said Etkin. “But psychotherapy hopefully has taught you skills that you can apply the next time you are in another traumatic situation.”

For some, one skill learned through trauma is to just keep going.

“No matter what kind of trauma you’re going through, even if it’s multiple times, you have to look at the bright side of life. You have to remember that you’re still here,” said Reno. “Every day I wake up, I have a smile on my face because I’m still here and I can do the things I love to do.”