Stress-related problem drinking among college students occurs when they have both a strong desire for reward and a weak fear of the dangers posed by their behavior, according to a new study from Duke University researchers.
Scoring poorly on exams, relationship problems and trouble at home are common stressors that can lead students to abuse alcohol. But a brain scan study of 200 undergraduates -- mostly from Duke with about a dozen from other North Carolina colleges -- demonstrated that stress-related alcohol abuse only occurred in students who had this specific combination of neural circuit functioning, researchers said.
"Imagine the push and pull of opposing drives when a mouse confronts a hunk of cheese in a trap. Too much drive for the cheese and too little fear of the trap leads to one dead mouse,” said senior author Ahmad Hariri, a professor of psychology and neuroscience at Duke and director of its Laboratory of NeuroGenetics.
The study provides a "novel mechanism for stress-related drinking by emphasizing the balance between reward and threat rather than only reward, which has been historically the focus of drug abuse research," he said.
The study appears online (http://www.biolmoodanxietydisord.com) Nov. 14 in theopen-access journal Biology of Mood & Anxiety Disorders. (Hariri is editor-in-chief of the publication, but had no role in the review of the paper.)
Hariri and lead author Yuliya S. Nikolova, a Duke graduate student, analyzed fMRI data to measure individual differences in the functioning of reward and threat circuits in the brains of the students. The students' self-reporting spanned the previous 12 months and included questions regarding their experience of stressful life events as well as their use of alcohol and any problems associated with this use.
In addition, a subset of students provided reports of their drinking three months after they were scanned, allowing Nikolova and Hariri to map differences in brain function onto later problem drinking.
The authors found that problem drinking related to stress emerged only in students who had both a highly reactive reward circuitry in the ventral striatum region of the brain and a hypo-reactive threat circuitry in the amygdala.
"The work further highlights a novel protective role for the amygdala, which has been historically the focus of risk for and pathophysiology of mood and anxiety disorders," Hariri said.
The findings may help with identifying individuals who are particularly high-risk for abusing alcohol because of stress, including biomarkers and interventions, Nikolova said.
The authors said an important caveat to consider when interpreting their findings is that participants may have experienced more stressful life events partially as a result of their increased drinking, rather than the other way around.
"This interpretation would be consistent with a heightened drive to pursue immediate rewards, coupled with a reduced ability to recognize and avoid threat in those individuals," they wrote.
CITATION: "Neural Responses to Threat and Reward Interact to Predict Stress-Related Problem Drinking: A Novel Protective Role of the Amygdala," Ahmad Hariri, Yuliya S. Nikolova. Biology of Mood & Anxiety Disorders, Nov. 14, 2012.