Some drugs are Kinda different because there are some that come from plants others come from labs. All drugs have differnt dangers and effects. The most popular drugs are alcohol, speed, downers, herb high ,ketaim, LSD, magic mushrooms, XTC, mescaline, onitnes, and crack.
One major long term effect after you do it so much is loss of memory. You won't remember anything you've done or where you are or have been.
Drugs can mess with your feelings. Your mood can swing from depressed to furious,and other feelings. It depends on the person.
Some ways to tell if someone is on drugs is that they become disrespectful. They may become angry, paranoid, or confused. They may suffer extreme mood swings. Another possibiliyy is that they may seem depressed or less out going than usual. They may be secritive and lie about what they have been doing or where they are going. They may steal or lose possesions they used to value. They may seem to have alot of money or ask for alot of money. Another thing they might do is take from family funds or money for family activities.