General Concepts ALL addictive drugs act on the dopamine mesolimbic-reward pathway Withdrawal symptoms are often the opposite of intoxication login to view 1 more bullet Depressant withdrawal is generally more life-threatening than stimulant withdrawal Injection drug users at risk for login to view 5 more bullets Depressants Opioids (e.g. morphine, heroin, methadone) login to view 23 more bullets Barbiturates login to view 13 more bullets Benzodiazepines login to view 14 more bullets Alcohol login to view 1 more bullet Stimulants Amphetamines login to view 9 more bullets MDMA ("ecstacy") login to view 9 more bullets Cocaine login to view 15 more bullets Caffeine login to view 7 more bullets Nicotine login to view 8 more bullets Hallucinogens PCP login to view 5 more bullets LSD login to view 9 more bullets Marijuana login to view 12 more bullets