Though not "hard and fast," the correlations suggested that alcohol was the problem, he said, adding, "in science there are levels of how sure you can be about something."
Durvasula also said the six to 20 drinks a day reported by the teens was "implausibly high." She recalled a study she did involving crack-addicted inner-city adult men who only averaged about eight drinks a day.
"They may have had a reporting problem," said Durvasula, also noting the large number of days the teens said they used drugs and alcohol.
The study did not control for socioeconomic level or education, both closely associated with the kinds of mental functioning measured in the study, said Durvasula.
Despite her comments, Durvasula said interventions are needed "both in the schools, and home-based" for teens who are at risk of substance abuse.
Thoma said large longitudinal studies could sort out the causes and effects in drug and alcohol-abusing teens, but noted the research "remains severely underfunded."
For more on teens' drug and alcohol use, visit the U.S. Substance Abuse and Mental Health Services Administration.
SOURCES: Robert J. Thoma, Ph.D., clinical neuropsychologist, assistant director, Adult Neuropsychology, Center for Neuropsychological Services, associate professor of psychiatry, University of New Mexico School of Medicine, Albuquerque; Ramani Durvasula, Ph.D., associate professor of psychology, California State University, Los Angeles; Oct. 19, 2010, Alcoholism: Clinical & Experimental Research, online
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