Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:
No Criminal Charges in Prince's Death
No one will be charged in connection with the overdose death of the musician Prince, Minnesota law officials said Thursday.
Prince died two years ago after unknowingly taking counterfeit Vicodin that contained the powerful synthetic opioid fentanyl, but there is "no reliable evidence of how Prince obtained" the drug, according to Carver County attorney Mark Metz, The New York Times reported.
"We have no direct evidence that a specific person provided the fentanyl to Prince," Metz said. He noted that the investigation did not find any "sinister motive, intent or conspiracy to murder Prince."
Minnesota doctor Michael Schulenberg, who treated Prince twice shortly before his death, has agreed to pay $30,000 to settle a federal civil violation for an illegal prescription, his lawyer, Amy Conners, said Thursday, The Times reported.
In a search warrant last year, investigators said Schulenberg told them he prescribed an opioid painkiller to Prince in another person's name in order to protect the musician's privacy.
As part of the settlement, Schulenberg admitted no liability, The Times reported.
The pills prescribed by Schulenberg did not lead to Prince's death, according to Metz.
"The bottom line is we simply do not have sufficient evidence to charge anyone with a crime in relation to Prince's death," Metz said.
FDA Should Approve Marijuana-Derived Epilepsy Drug: Advisory Committee
A marijuana-derived epilepsy drug should be approved by the U.S. Food and Drug Administration, an advisory committee unanimously recommended on Thursday.
If approved in an expected FDA vote in June, Epidiolex would be the first plant-derived cannabidiol medicine for prescription use in the U.S., CNN reported.
The committee recommended that Epidiolex, an oral solution, be approved for treatment of severe, early-onset forms of epilepsy in a small number of patients.
FDA approval would be for this use, but doctors would have the option to prescribe it "off-label" for other uses, CNN reported.
While Epidiolex would be the first plant-derived cannabidiol medicine approved for prescription use in the U.S., there are approved drugs that contain synthetic versions of cannabinoid chemicals found in marijuana.
The advisory committee's recommendation came after members reviewed data from the drug's maker, GW Pharmaceuticals PLC, CNN reported.
As Prescriptions for Opioids Fall, Use of Anti-Addiction Meds Rises
Prescriptions for opioid painkillers are declining in the United States while prescriptions for medications to treat opioid addiction are on the rise, new data show.
Prescriptions for opioid painkillers fell 10 percent last year, and new monthly prescriptions for the drugs fell by 7.8 percent, according to the IQVIA Institute for Human Data Science, which studies prescription drug use and spending, The New York Times reported.
The number of people in the U.S. who received new prescriptions for medications to treat opioid addiction nearly doubled during 2017, from 42,000 to 82,000 per month.
The decline in opioid prescriptions and increase in opioid addiction medication prescriptions reflects increased efforts to combat the nation's opioid epidemic, which claims 115 lives a day, The Times reported.
For example, there are new insurance company policies and state laws that limit opioid prescribing.
"I think the message is we are seeing measurable impact from all that's going on," Murray Aitken, executive director of the IQVIA Institute, told The Times. "These numbers don't tell you what exactly is driving the acceleration in the drop, but we think it's useful to get the 2017 numbers out there so people can see what's happening."
The report said that prescription opioid volumes reached their peak in 2011 at the equivalent of 240 billion milligrams of morphine. That fell by 29 percent to 171 billion in 2017, but that was still enough for every American adult to have 52 pills, "a fivefold higher level than in 1992," Aitken said.
Keeping Donated Livers Warm, Rather than Cool, May Help Them Last Longer: Study
Keeping donated livers warm, rather than cool, may keep them usable for a longer time and make more available for transplant, a new study suggests.
British researchers found that donated livers kept functioning when hooked to a machine that kept them at body temperature and full of blood and nutrients, the Associated Press reported.
In the study, 220 newly donated livers were either put into coolers as usual or stored for 24 hours in the machine made by Britain's OrganOx Ltd. Compared to the livers kept on ice, the warmed livers had less cellular damage, a risk for transplant failure.
And while the warmed livers were stored several hours longer than the cooled livers, 20 percent fewer warmed livers had to be discarded, according to the study published Wednesday in the journal Nature, the AP reported.
"The biggest challenge in liver transplantation is the desperate shortage of organs," said study leader Dr. David Nasralla, University of Oxford. "We found that livers that went on the machine were more likely to be transplanted."
This is "the first radically different approach to organ preservation," Dr. David Klassen of the United Network for Organ Sharing, which supervises the U.S. transplant system, told the AP.
He described it as "really exciting technology" that might prove appropriate for certain organ donations, but not all of them.
Similar machines are being considered for lung and heart transplants, the AP reported.
Nearly 115,000 people are on the waiting list for an organ transplant in the U.S., but last year there were just 34,770 transplants performed nationwide. Each year, thousands of people die waiting for a new organ.
Along with too few organ donations, storage times for donated organs are only about four to six hours for a heart or lung, and about 12 hours for a liver, the AP reported.
Early and Quick Turnaround Deployments Increase U.S. Soldiers' Suicide Risk: Study
U.S. soldiers have a higher risk of suicide if they're sent to a war zone soon after joining the military or if they have repeat deployments six months or less apart, researchers say.
They looked at 593 men and women in the U.S. Army who had been deployed twice and who attempted suicide between 2004 and 2009, NBC News reported.
"Those who served 12 or fewer months before their first deployment were approximately twice as likely to attempt suicide during or after their second deployment compared with those who had more time to train and acclimate to the military before initial deployment," Dr. Robert Ursano, of the Uniformed Services University of the Health Sciences, and colleagues wrote.
Soldiers who were re-deployed within six months or less were 60 percent more likely to attempt suicide, according to the study in the journal JAMA Psychiatry.
Short periods between deployments are common in the U.S. military as it sends troops to Afghanistan, Iraq and Syria, and there are rising rates of suicide among veterans. In 2014, an average of 20 veterans died by suicide each day, the Veterans Affairs Department says, NBC News reported.
"Rates of suicidal behaviors, including suicide deaths, attempts, and ideation, among U.S. Army soldiers increased considerably during the wars in Iraq and Afghanistan," Ursano and colleagues wrote.
The study findings make sense psychologically, Time Barclay, a clinical psychologist at the nonprofit Collateral Damage Project, which provides free mental health treatment to veterans.
Combat "literally changes the brain at a functional and cellular level," he told NBC News. "It causes an overreaction of the sympathetic nervous system that doesn't shut off."
Being deployed too soon after joining the military increases that stress, according to Patricia Spencer, who trains social workers about military culture.
These new soldiers "haven't had a chance yet to really bond with their unit, their squad," Spencer told NBC News.
"In suicide prevention we know that connections and having a sense of connection can be a protective factor. Somebody brand new into the military, they are not going to have quite that sense of connection with their unit and squad," she explained.