Teen drinking alters brain chemistry, suggesting early alcohol use has long-term effects on decision making, an animal study demonstrates. The findings could shed light on the development of alcohol and drug addiction. “In humans, the younger you are when you first experience alcohol, the more likely you are to experience problems with alcohol in adulthood," researchers say. The study bolsters the evidence that alcohol exposure early in life can have long-term effects on risk taking and decision making, which can increase a person’s risk for substance abuse problems.