The below information was gathered from NIDA (National Institute on Drug Abuse).  I encourage you to visit there site for additional information.  They are an EXCELLENT resource on drug and alcohol abuse.

Commonly Abused Drugs

Type of Drugs:  Cannabinoids

hashish ( boom, chronic, gangster, hash, hash oil, hemp )
marijuana (blunt, dope, ganja, grass, herb, joints, Mary Jane, pot, reefer, sinsemilla, skunk, weed )

How is it used?  either smoked or swallowed

What are the effects?
Mental:  euphoria, slowed thinking and reaction time, confusion, impaired or bad memory, learning skills impaired
Physical:  impaired balance and coordination, increased heart rate, coughing, red eyes
Social:  anxiety, panic attacks, tolerance or un-inhibited behavior

Type of Drugs: Depressants ( Central Nervious Systems )

barbiturates 
Perscription / Chemical Name:  Amytal, Nembutal, Seconal, Phenobarbital 
Code Name / Street Name:  barbs, reds, red birds, phennies, tooies, yellows, yellow jackets

How is it used?  either swallowed or injected

What are the effects?
Mental:  reduced anxiety, feeling of well-being, confusion, impaired memory
Physical:  slowed pulse and or breathing, low blood pressure, fatigue, impaired coordination, bad judgment, coma, death
Social:  lowered social anxiety, tolerance or un-inhibited behavior

benzodiazepines
Perscription Name:  Ativan, Halcion, Librium Valium, Xanax
Code Name / Street Name: candy downers, sleeping pills, tranks

How is it used?  either swallowed or injected

What are the effects?
Mental:  reduced anxiety, feeling of well-being, poor concentration, confusion
Physical:  slowed pulse and or breathing, low blood pressure, poor cslurred speach, possible coma, death
Social:  anxiety, panic attacks, tolerance or un-inhibited behavior

flunitrazepam
Perscription / Chemical Name:  Rohypnol
Code Name/ Street Name:  forget-me pill, Mexican Valium, R2, Roche, roofies, roofinol, rope, rophies
GHB
Perscription / Chemical Name:  gama-hydroxybuyrate
Code Name / Street Name:  Georgia home boy, grievous bodily harm, liquid ecstasy
 

Methaqualone
Perscription / Chemical Name:  Quaalude, Sopor, Parest
Code Name / Street Name:  ludes, mandrex, quad, quay

How is it used?  either smoked or swallowed or injected

What are the effects?
Mental:  reduced anxiety, feeling of well-being, poor concentration, confusion
Physical:  slowed pulse and or breathing, low blood pressure, slurred speach, poor reflexes, coma, death
Social:  anxiety, panic attacks, tolerance or un-inhibited behavior