ALARMING STATISTICS: A recent study by the National Institute on Drug Abuse revealed that 40 percent of all American high school seniors have used an illicit drug other than marijuana.

Most parents think they could spot the signs of drug or alcohol abuse in their teenagers. But that�s often not the case. Many times, parents attribute changes in behavior or attitude as typical of the growing process and not as symptoms of a substance abuse problem.

10 WARNING SIGNS: The ten symptoms of substance abuse described below are all signals that your teenager may have a problem. By familiarizing yourself with these signals, you, as a parent, can be better prepared to spot a problem with drug or alcohol abuse.

1. A sudden change in personality. Teenager suddenly becomes introverted or extroverted.

2. Changes in relationships with other members. Refusal to be involved in family activities.

3. A history of substance abuse in the family.

4. Being arrested or other trouble with law enforcement authorities.

5. Problems at school. Truancy or excessive absenteeism. A sudden drop in grades.

6. Dishonesty. Sneaking out of the house at night. Lying.

7. Changes in appetite, sleep habits or appearance.

8. Violent behavior, outbreak of temper, or unusual rebelliousness.

9. Known drug use or drug problems in friends.

10. Finding drugs or drug paraphernalia around the house or in the clothing.