Addicting? Dangerous?

Credit: Torben Bjørn Hansen via Flickr

In September 2012, the journal Cancer published results from a University of Southern California study showing that marijuana use doubles the risk of developing testicular cancer in men from their early teens to approximately 35 years old. This is the newest evidence revealing the risks of marijuana use. Although the drug has some therapeutic benefits, this article will address the risks associated with recreational marijuana use.

The effects of marijuana on the body are due to cannabinoids or more specifically tetrahydrocannabinol (THC). It is a psychoactive substance that can elicit both psychological and physical changes in the body. Some of these effects are of short duration while others can impact the body and brain permanently.

Psychological and Neurological Effects

In the short term, marijuana generates a sensation of euphoria and can lower one’s inhibitions. However, in other persons it can cause acute anxiety, paranoia or even panic attacks.

Multiple studies have revealed that cannabis increases the risk for developing psychotic disorders, anxiety, or depression. Data from the US National Comorbidity Survey show that suicide risk is also significantly increased among cannabis-dependent persons.

The drug also hinders short term memory. Some studies have even shown permanent, irreversible damage to intelligence and memory

Cannabis has also been shown to negatively affect driving skills by increasing the risk of accident nearly twofold. This is because the drug impairs visual tracking and attention.

Is marijuana addictive?

The risk of marijuana addiction is controversial, but many studies conclude that the drug can be psychologically and physically addicting. Also addicted individuals can suffer from withdrawal symptoms.

A large survey done in Australia in 2001 showed that dependence can lead to:

  • Withdrawal and needing the drug for withdrawal symptom relief
  • Unsuccessful attempts to control use
  • Tolerance (increased doses need to achieve the same effect) 

Effects on the lungs

When smoked cannabis exposes the lungs to carcinogens. Although the studies are inconclusive there is some evidence that suggests that there is an increased risk of lung disease (cancers, obstructive lung disease, etc...) associated with cannabis smoking.

Some suggest that the way marijuana is smoked (deep inhalation and holding of the breath) also increases the chance of lung damage. Some smokers develop a chronic cough and sputum production.

Effects on the reproductive system

In animal experiments, high doses of THC impair sperm motility and production. It also interferes with ovulation. Depending on the dosage and duration, marijuana can be potentially harmful to the human reproductive system.


While the degree of risk remains debatable in some areas, there is little doubt that recreational marijuana use can expose the user to serious potential long term health problems.




Adolescent marijuana use leaves lasting mental deficits, Psychology & Psychiatry, August 2012

Adverse effects of cannabis, Lancet, Nov. 1998

Cannabis use and dependence among Australian adults: results from the National Survey of Mental Health and Wellbeing, Addiction, 2001

Development and consequences of cannabis dependence. Journal of Clinical Pharmacology, 2002

EVIDENCE ON THE CARCINOGENICITY OF Marijuana Smoke, Reproductive and Cancer Hazard Assessment Branch Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, June 2012

Population-based case-control study of recreational drug use and testis cancer risk confirms an association between marijuana use and nonseminoma risk, Cancer, Sept. 2012