His drinking had begun to alarm his friends, he told Newsday in a 2010 interview. He began having car crashes, including once in his parents' garage and a collision with a telephone pole that broke his nose. And Jennings would disappear for days, refusing to take calls on his cellphone even from loved ones.
"You come back from an experience like that and you clearly are not the same person," Jennings, a 2001 Hofstra University graduate, told Newsday last year. "I just needed to be numb."
Jennings said after his drinking caused his girlfriend to leave him, he worked to get his life in order. He found a new love, Hatty Baldwin, whom he planned to marry. They settled in a home in Calverton.
But when Baldwin found Jennings dead on their bed when she returned home from work on the morning of Jan. 10, she and his parents wondered whether post-traumatic stress disorder might have driven him to suicide.
"He had a bagful of prescription drugs, I'd say 15 or more, that he would take every day," said his mother, Patricia Jennings, of Holtsville. "I don't think he wanted to live like that. He wanted to be fine, back to the way he had been before."
An autopsy report concluded Jennings' death was accidental. But it raised troubling questions about another threat that is an increasing concern among military and veterans groups: accidental poisonings by painkillers and other legally prescribed drugs.
Painkillers cited in death
The report, which Baldwin gave to Newsday, said Jennings died of "accidental intoxication" from two opiate painkillers, methadone and tramadol.
Military doctors nationwide wrote nearly 3.8 million prescriptions for painkillers in 2009, compared with about 866,800 in 2001, the year the war in Afghanistan began, according to the Pentagon. Doctors at the Northport Veterans Affairs Medical Center, where Jennings was an outpatient, wrote 18 percent more prescriptions for opiate painkillers in 2010 than they did four years ago, according to VA figures. In that time span the number of patients being treated at Northport increased by 1 percent.
His family said Jennings was taking more than a dozen legally prescribed drugs for pain and other conditions at the time of his death.
"I'm angry," Baldwin said. "It's nice to know it wasn't suicide, but it's upsetting and frustrating that he was on so many medications. It's much easier to prescribe stuff than to figure out what's wrong."
While declining to talk about Jennings' case, Dr. Hussein Foda, acting chief of medicine at the Northport VA hospital, said doctors there have taken measures to curb prescribing painkillers to veterans.
They have sharply reduced the number of dosages patients may receive at once, and patients suspected of abusing prescription drugs are subject to urine screenings and pill counts, he said.
"Someone coming in for a broken ankle will get a prescription for acute pain, but I think it is quite difficult to get a prescription for long term," Foda said. "We have a very vigorous narcotic pain management policy."
She said a military culture that often discourages soldiers from complaining about physical ailments may encourage individuals to become dependent on painkillers.
"You may think you are tough," LaBelle said. "So you take prescription drugs to dull the pain rather than get treatment, because there's still that stigma attached to asking for help."
She said the Defense Department ordered its doctors nationwide to limit more strictly how long patients may use opiate painkillers before seeking authorization for refills.
But veterans advocates say they are alarmed by the increased use of pharmaceutical drugs to treat soldiers for chronic pain. And with nearly one in five returning troops showing signs of PTSD or major depression, according to a 2008 Rand Corp. study, advocates say drugs are too often used to treat those affected by repeat combat tours or battlefield experiences.
Several meds needed
John Javis, projects director of the Veterans Health Alliance of Long Island, said veterans frequently incur war injuries that require multiple therapies. He said a soldier hurt in an explosion might be taking painkillers for a broken limb, anti-seizure medications to counter effects of a concussion, and anti-anxiety and sleep drugs for PTSD.
"We have clients who find it hard to stay awake during their meetings with us, and when you ask them, they are heavily medicated," Javis said. "On top of that, drinking is often a problem, and the interactions can be deadly."
Before Jennings' death, Newsday had been preparing an article on his struggle with PTSD.
In the interviews Jennings described being tormented by his experiences, including the aftermath of a suicide bombing in which the attacker's dismembered body was left near a checkpoint for several days.
Jennings showed a reporter a scrapbook of grisly photographs from Iraq, including portraits of more than a dozen fellow soldiers he knew who had been killed, and horrific images of Iraqi suicide bomb victims.
He described being traumatized by guilt over the deaths of two subordinates in his platoon -- Pfc. Francis Obaji, 21, of Queens, and Spc. Alain Kamolvathin, 21, of Blairstown, N.J. -- who drowned in a canal.
Baldwin said she found in Jennings' medicine chest more than a dozen prescribed drugs, including prazosin, used to curb PTSD nightmares; flurazepam, for insomnia; divalproex, for bipolar disorder, and bupropion, an antidepressant.
Jennings' mother said prescription drugs cast a cloud over her son's once vibrant personality.""He wasn't smiling anymore. Once or twice you would see the kind of person he was. But it wasn't often."