“We don’t just have an opioid epidemic, we have an addiction epidemic,” said Elizabeth Howell, M.D., of the University of Utah, at the recent American Association for the Advancement of Science Annual Meeting in Seattle. Helping people who use harmful substances—including alcohol or tobacco—is not a short-term treatment, she added. There is a progression from first using a substance that seems pleasurable to developing tolerance for it and eventually losing consistent control over its use—the definition of addiction. At that point, cumulative physiological changes have led to neuroadaptation. In essence, the brain signals that it is OK to use the substance again, despite negative consequences. These changes may never be entirely reversed. “Once a pickle, never a cucumber again,” she quipped. Lifelong treatment, including with medications, may be necessary.
Some of the substances to which people become addicted are administered directly into the bloodstream. Sharing equipment used for this purpose is one way to acquire HIV and/or hepatitis C (HCV). In 2017, one in 10 new HIV seroconversions in the U.S. were due to such drug use, the U.S. Centers for Disease Control and Prevention reported. However, people who seek care for HIV or hepatitis C are not routinely screened for substance use disorder, Howell noted. Conversely, her addiction clinic offers HIV and HCV testing and refers those testing positive to other providers. “We have a low HIV new infection rate, and most of our referrals are for HCV,” she explained.
While providers who prescribe medication for substance use treatment can attend trainings on drug interactions between these medications and drugs used to treat HIV or HCV, there are no regular refreshers on newly approved medications. “Methadone is the most problematic addiction medication to interact with HIV/HCV medications,” Howell wrote in an email. Nonetheless, it and similar drugs are an important component of successful substance use treatment. Without them, there is a 90% chance of relapse during a person’s first attempt at ending their substance use. “Medications do save lives,” she emphasized in her presentation.
Lives are also saved if people stop smoking tobacco, an addiction that causes one in five deaths in the U.S. annually. Smoking is more common among those living with HIV: 38% of people living with HIV smoked in 2014, compared to 18% of the general population in 2013. Switching to vaping might help people to quit cigarettes, Marina Picciotto, Ph.D., of the Yale School of Medicine, said at the conference.
“Vaped nicotine could be prescribed by clinicians to anyone who is an active smoker, and certainly could be one way to get vape pens to individuals at particularly high risk of smoking, such as people with HIV,” she explained. Nonetheless, vaping poses its own risks.
“We fought an incredibly successful campaign showing the public how harmful tobacco is,” she said. A similar campaign is now needed to keep non-smokers, and especially young people, from vaping, Picciotto added.
Banning flavors other than tobacco in vaping liquids could keep young people from trying it: “Psychophysical studies show that kids avoid tobacco flavor, but current tobacco users don’t mind it,” Picciotto explained. The earlier someone uses a harmful substance, the more likely they are to become addicted to it. “There is really some wisdom in this policy idea that you should wait with starting,” said Howell.
Adolescents tend to experiment not just with nicotine or other substances, but also with sex. However, to Picciotto’s knowledge, there aren’t any interventions that combine safe sex messages with promoting not smoking or taking drugs. “This is an interesting question for public health professionals, and would be a good way to get safe behavior messages to adolescents,” she commented, suggesting that organizations involved in public health messaging for teens might try such an approach.
Starting to use harmful substances at an early age does increase the chance of becoming addicted as an adult. However, 40% to 60% of a person’s vulnerability to problematic substance use is genetic. Animal studies have helped researchers find the specific brain chemicals and pathways that are affected by certain substances, as well as behavioral changes associated with exposure to tobacco, cannabis, or other substances at various stages of life. The science exists. Now policy needs to catch up.
“We need neuroscience-based research to guide policy decisions,” Joseph F. Cheer, Ph.D., of the University of Maryland, concluded at the conference.