By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) – Finally some good news regarding teens and substance abuse.

According to the National Institute on Drug Abuse, the rates of substance abuse among high school students continue to decline. This is based on a yearly poll of over 40,000 high school students.

It found that cigarettes, alcohol, prescription drug and over-the-counter drug abuse have declined over the last year in this age group.

Perhaps the most exciting news is that cigarette use went from 6.7% to 3.7%.

The news is not all positive, however. The rate of marijuana usage has not decreased and of particular concern is that e-cigarette use has now surpassed that of cigarette use in these age groups.

Many teens are not aware of the dangers of e-cigarettes. It does appear that preventive measures are helping.