KILLEEN, Texas » Pastor Randall Wallace of the First Baptist Church of Killeen has watched thousands of troops head off to war and then come home to Fort Hood, the mammoth base that shares this patch of Central Texas with an unpretentious jumble of pawn shops, fast-food joints and vinyl-sided bungalows.

"These are heroes," he reflected, "and yet they have problems. Sometimes, it’s too much alcohol. Sometimes, it’s too much stress. And then they wind up in the crime section, and we’re burying people," he said in the wake of Wednesday’s shooting spree by a soldier, the second in five years, that left four dead and 16 injured. For a decade, Fort Hood, which rose from cotton and corn farmlands as a training ground for World War II tank destroyers, was like a Grand Central Terminal for waves of troops heading out to Iraq and Afghanistan weekly. Soldiers deployed from this self-contained city where the streets on the base are named Hell on Wheels Avenue and Tank Destroyer Boulevard. Then they came back, many in need of counseling.

To many who live or pass through here, this is a primal slice of Americana shaped by patriotism, pride and a shared sense of mission, a company town where the company is the U.S. military and the heroes are ordinary soldiers. It’s the kind of town where the Taiwan Dragon Chinese restaurant, about a mile from the base, places the photos of soldiers – not celebrities – on its walls.

But now the wars are ending and the stress of combat and multiple deployment is being compounded or replaced by new anxieties. The number of soldiers assigned to the base has fallen from highs of more than 50,000, and could continue to shrink. And soldiers, many of whom had planned to make a career in the military, are looking at an uncertain path. A local nonprofit that works for soldiers’ rights says they are coming in regularly to deal with discharges from the military that have left them with few options for work.

"I don’t know what the future holds for our town," Killeen’s mayor, Daniel A. Corbin, said.

The base, which sprawls across 340 square miles, has an annual economic impact of roughly $25 billion and a footprint as large as Dallas. About 41,000 soldiers are stationed there, and every day, thousands of civilian workers drive through its gates to work, and veterans head in to exercise at the gym or catch up with old buddies.

"When they talk about Daytona, they talk about racing," said state Rep. Jimmie Don Aycock, who represents the area. "When they talk about Detroit, they talk about cars. When they talk about Silicon Valley, they talk about chips. When they talk about Killeen, they talk about soldiers."

But they have often been troubled soldiers. The shooting last week brought back sickening memories of the 2009 rampage on the base in which a former Army psychiatrist, Maj. Nidal Malik Hasan, killed 13 people.

Experts caution against stigmatizing a generation of soldiers with the actions of a few and note that most troubled soldiers are dangers more to themselves than to others. But they say demand for mental health services at bases has grown over time.

"Suicide, spousal abuse, sexual assault and mental health problems in general are issues that have come to the forefront in the last decade or so that my Army, in my day, did not see with this level of frequency," said Sam Floca Jr., 72, who is the honorary colonel of the regiment at Fort Hood, an unofficial title he uses to provide a link between past generations of soldiers and current ones. "It is more acceptable to talk about mental health issues today."

As the wars dragged on and soldiers returned after multiple punishing deployments, the pain increasingly has been felt at home, though episodes reported to the authorities have receded in recent years. Suicides at Fort Hood hit a peak of 22 in 2010, the largest one-year total on any Army post during the recent wars. Last year, the Lone Star Legal Aid office recorded 172 military-related family violence cases in a surrounding county, down from 250 in 2010.

But law-enforcement officials and advocates said soldiers were still struggling with the transition back. Lt. Donnie Adams, spokesman for the Bell County Sheriff’s Department, said there are surges in fatal motorcycle crashes driven by soldiers freshly returned from combat who "feel that they are invincible."

Legal advocates for soldiers said they were fielding calls from troops who had bolted from the base because they felt traumatized after deployments, or who were so heavily medicated for pain they struggled to wake up for morning formations.

Dr. Elspeth Cameron Ritchie, a longtime Army psychiatrist who is now chief clinical officer for the District of Columbia’s Department of Mental Health, said the wars had taken a toll on the base’s soldiers and families. In January, the husband of a soldier who had recently returned from a deployment to Afghanistan killed the couple’s two daughters before killing himself.

Fort Hood has placed greater focus on behavioral health issues for soldiers and their families, and runs a Resilience and Restoration Center dedicated to helping soldiers deal with combat stress, anxiety, anger management and other problems on their return. And even some victims of the 2009 still have fond memories of the base that remain unalloyed by the trauma of that day.

Even after she was shot four times in the back in that same hail of gunfire, Pfc. Amber Gadlin stayed on base at Fort Hood for more than a year and a half. Shortly after the November 2009 mass shooting, children were back on the playgrounds, she recalled. Soldiers enjoyed down time riding horse, had barbecues and jet-skied around the lake on base.

"After a while, people started to feel safe again," said Gadlin, who left the Army in 2011 and is now a stay-at-home mother in Albuquerque, N.M. "People still felt secure."

In the wake of Wednesday’s shooting rampage, military officials scoured the mental-health background of the gunman, Spc. Ivan A. Lopez, who committed suicide after a military police officer confronted him. Authorities said Lopez had been prescribed the sleep aid Ambien and was being treated for depression and anxiety. But military officials said there had been no signs he appeared dangerous, and they have not found any evidence he had been wounded in combat. On Friday they said an argument precipitated the shooting.

Some soldiers, veterans and elected officials said some personnel on the base should be allowed to carry concealed weapons to defend themselves, a position most military experts oppose. But few doubt that one of the most troubling aspects of violence on the base is that it comes in a place where soldiers should feel safe after returning from dangerous posts abroad.

Killeen has a long history of tragedy.

In 1991, a merchant seaman who had lost his job for possessing marijuana rammed his car into Luby’s Cafeteria in Killeen and opened fire, methodically killing 23 people before he shot himself. The markers in the nearby veterans’ cemetery bear witness to Iraq and Afghanistan’s outsize toll on the base – 519 troops from Fort Hood died in the Iraq War, and 56 died in Afghanistan. Corbin, the mayor, said attending solemn memorials and homecomings had become almost a way of life.

And with the 2009 incident still so fresh, many in the area were all too familiar with the pattern of shots and sirens. On Wednesday, the chief medical officer at Scott & White Memorial Hospital, which took in nine of the wounded, got word of the shooting through a short text message from someone on the post that began: "Sir, it happened again."

"I knew exactly what he was talking about," said the doctor, Stephen Sibbitt, whose hospital is east of Fort Hood and Killeen.

For Sgt. Jorge Sanchez, 29, it provided a somber exit note. Sanchez said had he survived "countless IEDs, countless firefights" after two tours in Iraq and one in Afghanistan before returning to Fort Hood, where he lives with his wife and two young children and works at a refueling station. In November, he said he was notified that he was being released from the Army after falling short on a physical-fitness test.

He was upset at first, but said it was time to move on after 11 years in the military. He said he is still haunted by memories of seeing his comrades killed, and takes Ambien to get to sleep. Sometimes, he says, his wife hears him cry out in his sleep, "They’re shooting at us!"

"The Army has changed," he said. "I can’t be a part of this."

Still, the base and the town’s military-drenched culture offers a sanctuary and a source of pride for many soldiers, active and retired.

In November 2009, Sgt. Alonzo Lunsford was shot seven times by Hasan. Lunsford, now retired, lost sight in his left eye and suffers from post-traumatic stress and recurring headaches, among other things, but he said he has fond memories of taking care of soldiers at one of the medical centers on base.

"Then all of a sudden on Nov. 5, everything changed," he said. "The reality is this: We have security measures in place for a reason. It’s like flying an airplane. Things happen but it is still the safest mode of transportation. Fort Hood and other military bases are the same."

Jack Healy, Serge F. Kovaleski and Alan Blinder, New York Times