A survey based on young adult college students indicated that symptoms of insomnia might buffer the association with the acute physiological effects of alcohol, in part because it may heighten the sensitivity to alcohol.
Angelo M. DiBello, PhD
New data from a survey study of 461 college students showed that symptoms of insomnia were associated with alcohol-related harm, with the associations between drinking and acute physiological consequences from the alcohol’s effects possibly buffered by the presence of insomnia symptoms.1 Insomnia symptoms have been previously linked to memory impairment, although they have not been associated with alcohol’s negative effects before this survey was conducted.
Predictors of acute physiological effects of alcohol use showed a significant amount of variance in blackout frequency (F[6, 441], 25.54; adjusted R2 = 0.25; P <.001) and blackout frequency with alcohol and insomnia (ΔF[1, 440], 16.22; ΔR2 = 0.03; P <.001). A follow-up test resulted in alcohol consumption being more strongly associated with blackout in low insomnia severity (B = 1.12; 95% CI, 0.90-1.34; P <.001) in comparison with high insomnia severity (B = 0.63, 95% CI, 0.46-0.79; P <.001).
Study coauthor Angelo M. DiBello, PhD, assistant professor, Center of Alcohol & Substance Use Studies and Applied Psychology, Department of the Graduate School of Applied and Professional Psychology, Rutgers University, said in a statement, “Because insomnia has been shown to impair memory and cognitive functioning, we thought that participants in our study with severe insomnia and high rates of alcohol use would also have the highest rates of blackout frequency.” He continued, “What we found was exactly the opposite."2
Participants in the study, published in the journal Addictive Behaviors, consisted of undergraduate students from a large Midwestern university who were at least 18 years old and reported heavy drinking in the past 30 days. The survey was given to the participants remotely with the aim of helping to improve the measurement of blackouts among young adults. To test the moderation model predicting blackout frequency, hierarchical linear regression was used, and for testing post hoc hypotheses, logistic regression was used.
Other findings from the survey showed that men (P =.003) were associated with fewer alcohol-related consequences. In addition, there were associations with more alcohol-related consequences with the use of other substances (P =.02), more depressive symptoms (P <.001), heavier alcohol consumption (P <.001), and more severe insomnia (P =.049). Also, the association of drinking and insomnia with feeling sick/vomiting and not being able to recall large stretches of time was significant (P <.05).
Another significant finding was insomnia’s association with drinking and having a hangover and passing out (P = .05). The analysis from the simple slopes showed heavy drinking was more strongly associated with the odds of each consequence with less severe insomnia than with more severe insomnia. Insomnia’s association between heavy drinking in the odds of neglecting obligations with more severe insomnia was significant (P <.001) compared with less severe insomnia (P = .93).
The results from the survey support past studies,3-5 in that more alcohol-related consequences were reported for those with insomnia in the past month than the participants who did not drink. In the previous studies, more severe insomnia and alcohol consumption were less strongly associated with alcohol-induced blackout, in contrast with the hypotheses of the survey study.
“We're not saying that the consequences of heavy drinking are absent for those with severe insomnia. This is not a license to drink heavily if you have trouble sleeping. What we are saying, however, is the effect is stronger for those who are low in insomnia," DiBello said in a statement.2 "But of course, people who are high in insomnia who drink a lot still experience elevated blackout frequency compared to those who drink less."
One of the limitations of the study was that it was not designed to test insomnia as a moderator of all acute physiological consequences of alcohol use. Another limitation was that the participants were mostly individuals who were Caucasian and college students who were women. Therefore, the results may not generalize other genders or across people from other racial and ethnic groups.1
DiBello that more work is needed to understand results that "are contrary to much of the established literature."2 Further research is needed for determining if less alcohol is needed to experience acute physiological effects for young adults with insomnia, if the alcohol heightens the sensitivity.1