Does using alcohol, nicotine, or cannabis engender addiction by changing the structure of brains, or does the structure of brains incline some people toward using those substances? In standard brain disease models of addiction, the neurotoxic effects of abused psychoactive substances are thought to cause brain changes that spur compulsive cravings for drink, smokes, or dope.
A recent study in JAMA Network Open, an open-access, peer-reviewed, international medical journal published by the American Medical Association, challenges that model and suggests that brain differences associated with addiction precede rather than result from substance abuse. A team of neuroscientists examined associations between brain structure and substance use initiation in nearly 10,000 children enrolled in the ongoing Adolescent Brain Cognitive Development (ABCD) Study.
Children aged 9 to 11 years were enrolled in the study. MRIs of each child's brain were taken at that time. None of the kids in the initial cohort reported using alcohol, nicotine, cannabis, or other psychoactive substances. During the next three years, the researchers periodically asked the kids, all still below age 15, if they had used any of those substances. Roughly a third of the kids (3,460), with some overlap, owned up to using either alcohol (3,123), nicotine products (431), cannabis (212), and other substances (213), such as inhalants, prescription sedatives, and hallucinogens.
