(CNN) The use of benzodiazepines, such as Xanax and Valium, is on the rise, and the number of overdose deaths related to them soared in recent years, new research says. 
 
 Benzodiazepines are a class of medication with sedative properties that are prescribed for anxiety, insomnia and other conditions. The potential danger of benzodiazepines is no secret: They were involved in about 30% of prescription drug overdose deaths in 2013, second only to opioids, which were involved in 70% of overdose deaths, according to the Centers for Disease Control and Prevention. 
 
 Researchers were hopeful that the last few years might see a decrease in benzodiazepine prescriptions. 
 
 "Going into this study, we thought that prescribing would be steady or decline in the late 2000s [because] people became more aware of opioids so there might be more attention" to benzodiazepines, said Dr. Marcus A. Bachhuber, assistant professor of medicine at Montefiore Medical Center and Albert Einstein College of Medicine. Bachhuber led the study, which was published in the American Journal of Public Health 
 
 But any hope that benzodiazepine prescriptions slowed was dashed as Bachhuber and his colleagues looked at national surveys of U.S. households taken between 1996 and 2013. 
 
 The survey data revealed that the percentage of adults in the United States who filled a benzodiazepine prescription per year increased by about 30%, from 4.1% in 1996, to 5.6% in 2013. In addition, the amount of benzodiazepine medicine -- whether Xanax, Valium, Ativan, Klonopin or other drugs in this class -- in a prescription doubled over this time period. 
 
 This trend is "very concerning," Bachhuber said. It is not clear what's driving the continued increase in benzodiazepine prescribing, whether more anxiety and insomnia are being diagnosed, or benzodiazepines are becoming more common go-to treatments for these conditions, he said. The study found that anxiety was the most frequent reason these medications were given, accounting for 56% of prescriptions. 
 
 Benzodiazepine 'shadow epidemic' 
 
 The study found that the overdose death rate related to benzodiazepines more than quadrupled between 1999 and 2010, from 0.58 per 100,000 adults to 3.07 per 100,000 adults. The largest increase was among adults 18 to 64 years of age. 
 
 Between 2010 and 2013, the rate of overdose deaths leveled off as they only plateaued among white adults, who make up the largest group of benzodiazepine users. Overdose deaths continued to rise among black and Hispanic people. 
 
 The fact that the overall rise in benzodiazepine overdose deaths between 1999 and 2010 was greater than the rise in benzodiazepine prescribing during this same period suggests that "people used benzodiazepines in more risky ways as time went on," Bachhuber said. 
 
 It could be that people were taking higher doses of medication -- which could be reflected in the increase in the amount of medication per prescription -- or they could be combining it with other medications, illegal drugs or alcohol, he said. 
 
 The big danger comes with mixing benzodiazepines with other substances. 
 
 "The risk of overdose and death from benzodiazepines themselves is generally low-to-moderate in otherwise health adults," said Dr. Gary Reisfield, professor of psychiatry at the University of Florida, who was not involved in the current study. But in combination with other sedatives, often opioids and alcohol, "their lethality is magnified," Reisfield said. 
 
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 The plateau in overdose deaths involving benzodiazepines, at least among white adults, is "reassuring to finally see," Reisfield said. There are probably a number of factors responsible for the plateau, he added, including the increase in statewide prescription drug monitoring programs, which collect data on substances that have been dispensed. Some states also require doctors to check these programs before prescribing painkillers, which could have helped reduce benzodiazepine overdose 
 
 The current study could help shine a light on the problem of benzodiazepine abuse and overdose. 
 
 "Much attention has been paid to the explosion of prescription opioid prescribing and the associated morbidity and mortality. Much less attention has been paid to the shadow epidemic of benzodiazepine prescribing and its consequences," Reisfield said. 
 
 Despite the recent leveling off in benzodiazepine overdose deaths, the data overall shows that efforts to curtail benzodiazepine prescribing, such as creating clinical guidelines, have not been successful, Reisfield said. 
 
 It is important for patients and providers to know about alternative treatments, and about the potential harms of benzodiazepines, both on their own and in combination with opioid painkillers and alcohol, Bachhuber said. ||||| Benzodiazepenes like Xanax (white) and Valium (blue) were involved in more than 30 percent of US deaths from prescription drug overdoses in 2013. 
 
 More than just an opioid crisis: Deaths from anti-anxiety drugs are on the rise, too 
 
 Deaths from opioids grab news headlines, government budgets, and the futures of troubled people. But these deadly drugs often have help. Benzodiazepines — underestimated and, some say, overprescribed — are killing people, too. 
 
 “There’s a lot of attention on opioids,” said Dr. Joanna Starrels, an internist and addiction medicine specialist at Albert Einstein College of Medicine in New York. “But I think that epidemiologists need to pay closer attention to the role of benzodiazepines in overdose deaths.” 
 
 According to the Centers for Disease Control and Prevention, more than 22,000 people in the United States died of overdoses involving prescription drugs in 2013, the most recent year with available records. Benzos like Xanax and Valium — a class of medications commonly prescribed for anxiety, insomnia, and other conditions — were involved in 31 percent of those deaths. 
 
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 To see how benzo use has changed in recent years, Starrels and her colleagues tracked prescription data and overdose numbers between 1996 and 2013. They found that the percentage of adults filling a benzo prescription increased by about 37 percent, from 4.1 percent to 5.6 percent, over the study period, while the overdose death rate shot up by more than 500 percent, from 0.58 per 100,000 adults at the turn of the millennium to about 3 per 100,000 throughout the early part of this decade. 
 
 “The rate of overdose deaths rose faster than the rate of prescriptions,” said Dr. Chinazo Cunningham, another study author from Einstein. 
 
 Why then might benzo prescriptions prove more deadly? “Our guess is that people are using these prescriptions in a riskier way,” said Cunningham, who, together with Starrels and their team, published the findings Thursday in the American Journal of Public Health. 
 
 A risk often taken by users is combining benzos with opioids, which can lead to difficulty breathing, coma, or death. “Prescribing opioids and benzodiazepines together is like putting gasoline on a fire,” said Dr. David Juurlink, head of clinical pharmacology and toxicology at Sunnybrook Health Sciences Center in Toronto, who was not involved with the study. 
 
 But benzos alone or in combination with alcohol are also to blame for some of the overdose uptick. And, as the Einstein researchers showed, it’s not just the number of benzo prescriptions but the quantity filled in each script that has risen in recent years. 
 
 “Benzodiazepines are grossly overprescribed,” Juurlink said, “and many people don’t necessarily benefit from them.” ||||| Breaking News Emails Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings. 
 
 More Americans than ever are overdosing on anxiety drugs, researchers reported Thursday — and it’s not clear why. 
 
 The new study finds not only that more Americans are taking the drugs, which include brand names such as Valium and Xanax, but that they’re taking more of them. 
 
 But while the quantity of prescriptions filled tripled between 1996 and 2013, the number of overdoses quadrupled during the same period, the team reported in the American Journal of Public Health. 
 
 "We found that the death rate from overdoses involving benzodiazepines, also known as 'benzos,' has increased more than four-fold since 1996 — a public health problem that has gone under the radar," said Dr. Marcus Bachhuber of the Albert Einstein College of Medicine in New York, who helped lead the study. 
 
 "Overdoses from benzodiazepines have increased at a much faster rate than prescriptions for the drugs, indicating that people have been taking them in a riskier way over time." 
 
 Benzodiazepines are extremely popular drugs in the U.S. 
 
 Related: Drug Overdose Deaths Hit Alarming High 
 
 More than 5 percent of U.S. adults fill a benzodiazepine prescription every year, for conditions such as anxiety, mood disorders and insomnia. 
 
 They’re known to be highly addictive and, in 2013, nearly a third of the 23,000 people who died from prescription drug overdoses were taking them. 
 
 Bachhuber’s team looked at large health surveys to find trends in their use and abuse. 
 
 “The rate of overdose deaths involving benzodiazepines increased more than four-fold from 0.58 per 100,000 adults to 3.07 per 100 000 adults,” they wrote. “However, this rate appeared to plateau after 2010.” 
 
 “Between 1996 and 2013, the number of adults filling a benzodiazepine prescription increased 67 percent, from 8.1 million to 13.5 million,” they added. 
 
 They found a similarly large increase in the number of pills each adult was prescribed. 
 
 It’s not clear why overdoses went up so much. It could be people are taking the drugs for longer times, raising the odds that they’ll eventually overdose. Or it could be the pills are getting to people who don’t have prescriptions, the researchers wrote.
– Opioids aren't the only drugs we should be concerned about when it comes to overdoses. ODs involving common anxiety drugs like Xanax and Valium are at an all-time high, and scientists fear plenty of lives will be lost before they fully understand why. In a new study, researchers found that prescriptions for benzodiazepines—used to treat anxiety, mood disorders, and insomnia in more than 5% of US adults—tripled from 1996 to 2013, while overdoses quadrupled, reports NBC News. In 2013, "benzos" played a role in 31% of the nation's 22,000 prescription overdose deaths, reports STAT. Seeing the rise in ODs outpace the rise in prescriptions suggests "people have been taking them in a riskier way over time," says lead author Marcus Bachhuber. One theory is that the spike in deaths is linked to higher doses—the amount of benzodiazepine in prescriptions doubled over the study period, notes CNN. It's also possible that people are taking them carelessly along with alcohol or opioids, in which case their "lethality is magnified," says a doctor not involved with the study. The death rate plateaued among white people, the largest users of benzos, between 2010 and 2013, but it rose among black and Hispanic people in that same span. The authors caution that benzodiazepines are being over-prescribed in general and suggest doctors should look into alternatives drugs or treatments such as talk therapy.