Opiates taken as a pill or tablet take longer to reach the brain.
Individuals who take antidepressants and anti-anxiety medications can develop dependence to these drugs and may experience withdrawal syndrome if they suddenly stop taking them.
Over 20 percent of high school seniors reported using marijuana in the past 30 days in 2010, while 19.2 percent smoked cigarettes.
Methadone can be prescribed by a doctor for pain relief, but can only be prescribed for addiction treatment by physicians who liaise with methadone clinics.