One of the most effective methods to discourage hard drug use is to showcase the drugs' harsh effects on a user's body, according to Rehabs.com, which offers addiction information and connects users with treatment programs nationwide.

Rehabs.com created an infographic featuring photos of oxycodone, heroin, and cocaine users arrested for drug offenses over a period of time. The infographic details each drug's specific effects on the body, such as weight loss and facial sores. (The infographic carries a disclaimer that the appearance of the individuals pictured may not necessarily result from illegal drug use, though the people were arrested for drug-related offenses.)

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Rehabs.com showed the photos to people and surveyed them about their attitudes after viewing the images. The results were striking.

• More than 60 percent of respondents to the survey said that the photos made them "more likely to support greater access to addiction treatment."
• Around 40 percent said that seeing the physical effects of drug addiction made them feel "more compassionate" toward drug addicts.
• About 90 percent said that the photos made them "less likely to abuse drugs."

This video highlights more of the results: 

Americans' use of cocaine and drugs other than marijuana decreased between 2007 and 2013, while the number of marijuana users increased from 14.5 million in 2007 to 19.8 million in 2013, according to a survey by the National Institute on Drug Abuse.

Marijuana doesn't appear to have the same devastating physical effects on the body that oxycodone, heroin, and cocaine seem to. Marijuana use correlates with lower body mass indexes and rates of diabetes.

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Marijuana has also been shown to be effective as part of cancer treatments, as it was for 13-year-old Chico Ryder, who used it to help deal with his parameningeal embryonal rhabdomyosarcoma. The National Cancer Institute recently confirmed that cannabis kills cancer cells.