When Alex was 12 years old, she took her first drink -- alone.
It was the same for cigarettes and marijuana. "I did it alone, because I felt uncomfortable in social situations. Every night I would get really depressed … and felt the need to always be high," she said.
Substance abuse has always been a major worry for parents of all teenagers, but it may be teens like Alex -- who drink, smoke or take drugs alone -- who are at the biggest risk, according to researchers at the Rand Corp., a think tank in Santa Monica, Calif.
Research shows that teenagers who use alcohol, tobacco or marijuana, either when by themselves as well as in social situations, are less likely to graduate from college and more likely to experience substance abuse problems and worse physical health than their peers who use these only when with other people.
The study followed more than 3,000 teens from California and Oregon, from the eighth grade until they were 23 years old. The teens were split into two groups -- those who abused substances only in social situations (the "social-only" users), and those who reported drinking or smoking alone but who also engaged in social smoking or drinking (the "solitary users").
"I would have thought that socially isolated kids would be more likely to be solitary users," said Elaine Leader, a psychologist and executive director of Teen Line, at the Cedars-Sinai Medical Center in Los Angeles. But social isolation does not appear to be linked to drug use when alone.
"It seems that [the solitary users] are putting a priority on partying [instead of] devoting themselves to the tasks of adolescence," like studying or sports, she said.
By the age of 23, these same solitary users were more likely to experience drug abuse problems and poorer health than the teens who used substances only when in social situations.
"I thought [the study] made a lot of sense," said Alex. "For addicts and alcoholics, there is something that clicks in the brain, and you need it."
Moreover, solitary smokers and drinkers were also less likely to graduate from college and more likely to engage in violent behavior, according to the study.
Solitary users also took drugs more frequently -- three to five days a month compared with less than one to two days a month by social-only users. And this group used more drugs in general, smoked more cigarettes and marijuana and drank more beverages than their social-only counterparts.
"The reality is that there are kids that use on their own, and they're using a heck of a lot more" than peers who engage in drug use or drinking only when with their peers, said Brian Meyer, executive director of the Virginia Treatment Center for Children in Richmond, Va.
"Eighty-five percent of kids have tried a substance before they leave high school," said Meyer. In the study, 16 percent of the teens were smoking alone, 17 percent were drinking alone, and 4 percent were using marijuana alone by the eighth grade.
Meyer said the study may change the way teenage substance abuse treatment is structured.
"It tells us that we really need to rethink our notions on the treatment of solitary users and focus on them much more heavily," he said.
Moreover, research may shift to focus more on what leads a teen to become a solitary user of drugs and alcohol.