Marijuana: Harmless vs. Harmful

Marijuana has been a subject of controversy for years; users tout its medical benefits and relatively harmless effects, while opponents cite studies that show detrimental effects on users’ brains and the likelihood that marijuana is a gateway drug to more hardcore drug abuse.


First, let’s see some people say about marijuana being harmless, with medical benefits.

  • Studies conducted at UCLA in 2005 and at Kaiser Permanente in 1997 examined the records of more than 65,000 patients and found that there was no evidence linking marijuana to cancer. (1)
  • According to federal data, marijuana treatment admissions referred by the criminal justice system rose from 48% in 1992 to 58% in 2006. Just 45% of marijuana admissions met the Diagnostic and Statistical Manual of Mental Disorders criteria for marijuana dependence. (2)
  • The InfoFacts page on states: Marijuana has been shown to be effective in reducing the nausea induced by cancer chemotherapy, stimulating appetite in AIDS patients, and reducing intraocular pressure in people with glaucoma. There is also appreciable evidence that marijuana reduces muscle spasticity in patients with neurological disorders. (3)
  • According to Fred Gardner, managing editor of a leading pro-cannabis research magazine, The National Institute on Drug Abuse “looks for the negative stuff on purpose, and disregards anything positive about cannabis. This medicine actually has great benefits, and more people need to know that.” (1)
  • “Nature gives us everything for a reason,” Steve DeAngelo, whose cannabis dispensary is the largest in the country, said. “It doesn’t make any mistakes. And with cannabis it gave us the single most valuable plant on the planet – no plant can cure so many illnesses and relieve so many symptoms. People need to know that.” (2)


Others, including many health officials and the government, tell a different story of marijuana, one that involves addiction, mental illness and a transition to harder drugs.

  • The National Institute on Drug Abuse states that marijuana contains 70% more carcinogenic hydrocarbons than tobacco, increases a user’s heart rate by as much as 100%, and can worsen anxiety and depression. (1)
  • Research by Harvard University says that marijuana is responsible for 14% of car accidents involving injuries, that people who become addicted mostly say it’s degraded their lives, and that inhaling pot smoke damages lungs. (1)
  • A 2006 paper issued by the DEA, based on research by the national Substance Abuse and Mental Health Services Administration and other agencies, contended that 14.6 million people had smoked or otherwise ingested marijuana over a recent one-month period, making it the most commonly used illegal drug in the nation. It also said more people ages 12-17 entered rehabilitation treatment programs for marijuana dependence than for alcohol and all illegal drugs combined. (1)
  • says that long-term marijuana abuse can lead to addiction. 9% of users become addicted to marijuana; this number increases among those who start young (to about 17%) and among daily users (25-50%). (3)
  • “Some people think marijuana is just something they may have used when they were younger, and have different perceptions about its harmfulness, but we want people to know that there are risks out there,” said Susan Weiss, a policy chief for the drug abuse institute. “It’s not just harmless, especially for young people.” (1)

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