To detect

According to me, I think that we can detect the drug abuse because we can see the different of attitude. Actually teenager who becomes drug abuse would like to live in their world imagination. There are some sign to detect them:
• Evidence of eye drop used to mask bloodshot eyes or dilated pupils
• Declining and increased absences in school performance.
• Like to stay alone, withdrawal from hobbies, friends and family
• Changes in energy level, having unusual amount of energy .
• Keep secrecy about his /her activity from parents and best friends.
• Sometimes look tired and angry.
• Like to bring a pink pill (ecstasy)
• Requests a lot of money than usually and etc.