CRESCENT, Okla. — Hours before dawn on a March morning in 2015, Josh Holley woke to his worried mother knocking on his bedroom door.

Your brother's downstairs in the bathroom, she told him. He's sick, and he's yelling.

When Josh found his younger brother, Jeffrey, a U.S. Army veteran who had been discharged for medical reasons four months earlier, Jeffrey told him not to worry, he only had a stomachache. Josh asked if he needed anything. Jeffrey said he didn't, so Josh turned to walk back upstairs. But before he could leave, Jeffrey said something that caught Josh by surprise.

"I love you," Jeffrey said. The comment struck Josh as strange. It wasn't the way Jeffrey usually talked. But Josh didn't think much of it.

"I love you too, bro," he answered. "Try and get some sleep."

Josh went back to bed. An hour later, he woke again to his mother pounding on his door. He opened the door to find her in tears.

I just heard a gunshot, she told him. Tell me where your brother is.

The two searched the house and the front yard, but didn't find him. Finally, Josh ran into the backyard. Immediately, he spotted the old wooden shed at the edge of the yard. The door was standing open.

"I knew in my heart he was in there. I prayed that he wasn't, but I knew," Josh said. "I opened it, and we found him. He'd shot himself in the head."

Jeffrey Holley was one of 159 military veterans who took their own lives in Oklahoma in 2015, according to figures from the Oklahoma Department of Mental Health and Substance Abuse Services. Only 21 at the time of his death, he is a part of a pattern that has troubled mental health providers, veterans advocates and policymakers: young Oklahoma military veterans dying by suicide in alarmingly high numbers.

Across all age groups, Oklahoma's military veterans die by suicide at a higher rate than do veterans nationwide, according to a U.S. Department of Veterans Affairs report released in September. But among veterans age 18-34, Oklahoma had the highest rate of suicide in the nation, the report shows.

The report is based on veteran suicides reported in 2014 and population estimates from the U.S. Census Bureau's 2014 American Community Survey.

According to the report, 149 veterans died by suicide in Oklahoma in 2014, or 53.8 veteran suicides per 100,000 veterans. The national rate of veteran suicides is 38.4 per 100,000 veterans.

Among veterans age 18-34, the state saw 33 suicides in 2014. That total gives the state a suicide rate of 122.3 per 100,000 veterans in that age bracket, far outpacing the national rate of 70.4 per 100,000 veterans.

Regardless of their ages, Oklahoma's veterans are far more likely to die by suicide than nonveterans. From 2005 to 2012, the state's veteran suicide rate was 39.2 per 100,000, compared with 18.2 per 100,000 among nonveterans, according to a report from the Oklahoma Department of Health.

The number of Oklahoma veterans who die by suicide each year has grown in recent years, climbing from 110 in 2005 to 159 in 2015 — a 44.5 percent increase, according to figures from the Oklahoma Department of Mental Health and Substance Abuse Services.

Advocates point to a number of factors they say are to blame for the state's high rate of young veteran suicides, including a high rate of substance abuse, ready access to firearms and problems young veterans face managing the transition from the military to civilian life.

But more than any other single factor, advocates point to a lack of available treatment for mental health and addiction issues as a key driver of the rate of suicides among Oklahoma veterans, the Oklahoman reported.

Jeffrey Holley served as an artillery crew member stationed at Fort Wainwright, just outside of Fairbanks, Alaska. Before he joined the Army, Jeffrey had smoked marijuana, but he'd never done any harder drugs, his brother said.

But that changed after Jeffrey enlisted, Josh said. Like many military service members, Jeffrey began smoking synthetic marijuana, or K2, thinking it wouldn't show up on the Army's mandatory drug screenings. But the chemical makeup of K2 often varies from one batch to the next, and its effects can be difficult to predict.

In 2012, Jeffrey came home from Alaska on leave. During a night of partying with old friends, Jeffrey smoked K2 and took an entire box of cold medicine, his brother said. He came home the following morning complaining of a stomachache. That evening, his mother found him lying unconscious on the bathroom floor.

Jeffrey was in the hospital for the next two weeks after the overdose. Although he survived, the incident left him with lasting medical issues. After about a month at home, Jeffrey returned to Alaska. But the Army gave him a medical discharge, and he returned to Oklahoma in November 2014.

After he came home, family members tried to talk to Jeffrey about his drug use. Once, they staged an intervention. None of it did any good, Josh said. Jeffrey insisted he could quit anytime he wanted.

"He didn't think he had a problem," he said. "That was the problem."

But drugs weren't the only problem. After he came back to Oklahoma, Jeffrey had a hard time finding work. He talked about looking for a job as an oil-field worker or trying to re-enlist in the Army. But mostly, he seemed unsure of what he wanted to do with his life.

Looking back on it, Josh can point to signs that his brother may have been depressed. He'd always had lots of friends and enjoyed spending time with them, Josh said. But after he was discharged from the Army, he became withdrawn and spent most of his time at home. At the time, though, the warning signs were difficult to see.

Many problems contribute to Oklahoma's high rate of veteran suicides, and no single factor can explain the entire trend, said White, the state mental health commissioner. She compared the issue to an image on an overhead projector: One projector transparency may only show part of the image, but with two or three more laid over the top, the full picture begins to appear.

The good news, White said, is that help is available for veterans in crisis. She encourages people to call the National Suicide Prevention Lifeline for help. The hotline has special services tailored toward veterans who are at risk of suicide, she said.

April 9 would have been Jeffrey Holley's 25th birthday. Josh and Jeffrey's father and stepmother invited the family over and made Jeffrey's favorite dinner — chicken-fried steak with mashed potatoes and gravy. And, like she does every year, their mother bought Jeffrey a birthday cake from a local bakery. On the cake, the words "Jeffrey — Happy 25th birthday in heaven" were spelled out in white icing.

Special days like Jeffrey's birthday and the anniversary of his death are always difficult, Josh said. And holidays always serve as a reminder of who is missing at the dinner table. When they talk about Jeffrey, the family mostly dwells on happy memories like his days as a lineman for the Crescent High School football team or goofy things he did to get a laugh.

In the three years since his brother died, Josh has come a long way. He and his parents go to a support group, which has helped him open up about his feelings.

Josh still has bad days. Sometimes, he gets angry with Jeffrey for taking his own life. Then he gets angry with himself for feeling that way. The support group has helped him understand that those feelings are normal, he said.

Before his brother died, Josh didn't know much about Oklahoma's high rate of veteran suicide. He suspects most Oklahomans don't know any more than he did. Children in school learn to say no to drugs, he said, but nobody teaches them about the state's suicide epidemic.

Josh hopes to see people become more willing to talk about suicide. More conversations about the issue could help people spot signs that their loved ones might be at risk, he said.

Mostly, he said, he wants to see the state do a better job of preventing young veterans like his brother from taking their own lives.

"It's rampant. It's terrible," Josh said. "I don't know the answer. But soldiers deserve better."

If you or someone you know is considering suicide, call the National Suicide Prevention Lifeline at 1-800-273-8255. Veterans may press 1 to be directed to the Veterans Crisis Line. Distributed by The Associated Press.