Technically, nicotine is not significantly addictive, as nicotine administered alone does not produce significant reinforcing properties. However, only after coadministration with an MAOI, such as those found in tobacco, nicotine produces significant behavioral sensitization, a measure of addiction potential. This is similar in effect to amphetamine.
Modern research shows that nicotine acts on the brain to [...]

Marijuana is the most commonly abused drug. A dry, shredded green/brown mix of flowers, stems, seeds, and leaves of the plant Cannabis sativa, it usually is smoked as a cigarette (joint, nail), or in a pipe (bong). It also is smoked in blunts, which are cigars that have been emptied of tobacco and refilled with [...]