Finding clues to prevent alcohol problems
A new CAMH study reveals how important responses to alcohol interact to influence a person's drinking behaviours. These responses, including whether a person feels energized or drowsy after consuming alcohol, could predict the likelihood of developing alcohol problems at the time of greatest risk: the young adult years.
It’s also one of the first studies using a novel technique – intravenous alcohol self-administration (see sidebar below) – to look at how individual differences affect alcohol consumption.
"Young people aged 18 to 24 present the highest rates of heavy drinking and associated problems, which may include alcohol dependence, injuries, risk taking, drinking and driving, and problems in school," says Dr. Jeffrey Wardell, post-doctoral fellow with the Campbell Family Mental Health Research Institute at CAMH and an investigator on the study, published in the Journal of Abnormal Psychology. "This group is a prime target for prevention and intervention."
"The overall goal of our research is to assess behavioural and brain responses to alcohol in young adults and examine these responses in relation to future risk for alcohol problems,” says Dr. Christian Hendershot, Senior Scientist in the Addictions Division and the Campbell Family Mental Health Research Institute at CAMH, who led the study.
Observing the interplay
People respond in several key ways after consuming alcohol – they may experience stimulation (feeling energized), sedation (feeling drowsy or tired), craving (desire to drink) and impaired control (difficulty controlling how much alcohol they consume, resulting in drinking more than they intended). The researchers sought to determine how these factors affect one another and, ultimately, how much alcohol a person chooses to consume. (Dr. Vijay Ramchandani, Chief of the Section on Human Psychopharmacology at the U.S.-based National Institute on Alcohol Abuse and Alcoholism, was a co-investigator on this study.)
"Impaired control is thought to be a hallmark of alcohol use disorder, and is a trait that develops earlier in people, so it could be one of the earlier signs of risk for alcohol use disorder," says Dr. Hendershot.
The researchers narrowed their focus to young, healthy social drinkers aged 19 to 21 who had a heavy drinking episode at least once in the previous month. (This meant four or more drinks for women; five or more drinks for men).
Sixty-two people participated in a two-hour session of intravenous (IV) alcohol self-administration. First, participants completed a questionnaire assessing impaired control. After receiving an initial IV infusion of a certain amount of alcohol, they could choose to consume more by pressing a button as little or as often as they wished, up to a predetermined safety limit. Participants were instructed to self-administer alcohol to a level they found pleasurable while avoiding negative effects. At fixed times, they completed a computer survey reporting about how stimulated or sedated they felt, and their desire or craving for more alcohol. Participants also breathed into a breathalyzer at regular intervals to measure blood alcohol concentration.
Craving as mediator
From these data, the researchers examined how responses to alcohol affected their pattern of self-administration.
People who reported higher stimulation, lower sedation and stronger craving were more likely to self-administer alcohol. More specifically, "stimulation predicted craving, and craving predicted self-administration," says Dr. Wardell. "So we see that craving is a mediator."
From person to person, the researchers saw a wide range of differences in how an individual’s responses to alcohol consumption affected their further consumption, from people pressing just once, to self-administering up to the safety limit.
"Craving and self-administration are not the same for all people. Impaired control predicted the strength of the relationship," explains Dr. Wardell. People with higher impaired control – who reported that they experienced difficulty controlling how much alcohol they consumed in the past – were more likely to self-administer alcohol in response to craving. People with low impaired control were not as likely to self-administer when they craved more.
Dr. Wardell says these findings may provide opportunities to intervene to prevent the onset of alcohol use disorder. "This research shows that differences in how alcohol affects people in the moment are risk factors for heavier consumption, and there is an opportunity to raise awareness of these risks," he says.
This study was supported by ABMRF/The Foundation for Alcohol Research, as well as the Canadian Institutes of Health Research.