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Q&A: Effects of marijuana
By Online Staff , Herald-Tribune
/ Tuesday, January 14, 2014
Q: With Colorado the first state to allow legal sales of marijuana for recreational use, Washington state will do the same later this year, and other states might follow suit. What are marijuana's effects on the body?
A: The main active ingredient in marijuana — a greenish-gray mixture of leaves, stems, seeds and flowers of the cannabis plant — is delta-9-tetrahydrocannabinol, or THC. It binds to the surface of nerve cells in high-density areas of the brain involved in feelings of pleasure, memory, thinking, concentration, coordination and movement, and sensory and time perception. THC stimulates this communication network, resulting in a marijuana "high."
About 20 states allow the use of marijuana for medical purposes. Most patients are seeking the drug for controlling pain for medical issues including cancer, nervous system diseases, glaucoma and migraines. It is also being used to treat nausea and improve appetites for people with HIV or other chronic illnesses.
When the leaves are smoked, THC moves almost immediately from the lungs to the bloodstream and to the brain. The effects can last one to three hours. If it's eaten, say in brownies or cookies, it can take 30 minutes to an hour to have an effect, but the high can last up to four hours.
In the short-term, it can lead to a rapid heart rate, increased blood pressure, red eyes, dry mouth, increased appetite and slowed reaction time. Long-term use has been linked to impaired thinking, memory problems, panic attacks and other psychological issues. Studies have shown a weakened immune system and, for those who smoke the drug, impaired lung function.
There are no recorded cases of someone dying from an overdose.
The concentration of THC in seized samples of illegal marijuana has been increasing over the past 30 years, with the average potency more than doubling since 1998. But scientists don't know much about the effects of higher concentration on the body and brain.
Long-term use, especially by those who start at a young age, has been shown to lead to addiction, with an estimated one out of 11 people who use it becoming dependent on it. Withdrawal symptoms are similar to those of withdrawal from smoking and include irritability, sleep difficulties and anxiety.
Last year Canadian and American researchers reviewed more than 120 studies examining cannabis and its effects on the teenage brain. They found strong indications that early marijuana use can alter development and contribute to mental health problems later in life.
"For me, the question is not about whether cannabis is good or bad, but who is more likely to suffer from problems in cannabis, because we know for most people that will not happen," Didier Jutras-Aswad, one of the study's authors and a University of Montreal neuroscience professor, told the Canadian Broadcasting Corp.
A number of studies have shown that babies born to some women who regularly used marijuana suffered from an increased risk of cognitive and attention deficits, memory and learning issues, low birth weight, pre-term delivery and other issues. But more research is needed to figure out to what extent environmental factors played a role.
– Brady Dennis and Ariana Eunjung Cha, The Washington Post
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