Although teens who started smoking at an early age were at increased risk for alcohol dependence and substance use disorders in their late 20's, they did not appear to be at an increased risk for depression or other psychiatric disorders. However, initiating tobacco use in late adolescence was associated with depression and other psychiatric disorders in the late 20s.
These findings are based on a 22-year study that tracked the self-reported substance abuse and health histories of 736 youths through their early-and mid-teen years into early adulthood. Scientists from the Mount Sinai School of Medicine and Columbia University started collecting data on the children in 1975, when the subjects were one through 10 years of age. Four follow-up interviews were conducted: in 1983, 1986, 1992, and 1997, when the average ages of the subjects were 14, 16, 22, and 27 years.
During mid to late adolescence, 18.8 percent of the subjects reported moderate to heavy tobacco use; 6.2 percent reported moderate to heavy alcohol use; 17.6 percent reported moderate to heavy marijuana use; and 3.4 percent reported moderate to heavy use of other illicit drugs. During young adulthood, these percentages increased to 35.4, 13.0, 18.4, and 3.7, respectively.
In 1997, when the subjects were in their late 20s, 8.3 percent qualified for a diagnosis of a major depressive disorder (MDD), 5.2 percent were alcohol dependent, and 6.1 percent had a substance use disorder. Heavy alcohol, marijuana, and other illicit drug use were significantly related to later psychiatric disorders. About 85 percent of the individuals diagnosed with MDD in their late 20s had used marijuana when they were younger and more than 66 percent had a prior history of alcohol and/or other illicit drug use.
WHAT IT MEANS: This study adds to the growing body of knowledge about the complex relationship between drug abuse and psychiatric disorders. Such findings will be useful in efforts to develop more effective prevention and treatment interventions for individuals at risk for these co-occurring conditions.
Dr. David Brook and colleagues published the study, which was supported by the National Institute on Drug Abuse, in the November, 2002 issue of the Archives of General Psychiatry.