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Routine marijuana use may damage a teen’s developing brain

Smoking marijuana isn't without potential long term consequences. It could damage a teen's developing brain, and lead to a reduction in IQ, other drug use, and mental health issues.

We often hear marijuana isn't that dangerous of a drug. In reality, regular use of marijuana may permanently damage a teen's developing brain – and could lead to a reduction in IQ, other drug use, and mental health issues.

I heard a frightening and eye opening lecture by Dr. Sharon Levy of Children's Hospital Boston about the effect of marijuana on the developing brain earlier this month at the Pediatric Academic Societies meeting in Washington, DC.

Smoking marijuana has all the known side-effects of smoking tobacco except nicotine addiction.  So a heavy and early smoker of marijuana is increasing the probability of chronic lung disease and cancer as he or she builds up "pack-years."  But the active ingredients in marijuana are dozens of different cannabinoids of which the best known is THC (tetra-hydro-cannabinol). The effect of these active drugs is at the endocanninoid site (also called the anandamide receptor) in the brain.

The active ingredient of marijuana 15 years ago was 4 percent of the total breathed in, but through careful cross-breeding, cultivators of the plant have achieved an average of 9 percent or more in current available product. Street marijuana is now more than twice as strong as it was 15 years ago.

The cannabinoids affect the brain's pleasure centers causing relaxation followed by excitation, but because these active drugs are fat-soluable  (get into body fat) the relaxation extends for a prolonged time and when the subsequent excitation (acting hyperactively) occurs, the teen does not relate it to using the drug.  The same site that cannabanoids act on is the site that organizes the brains cells to act with each other and with the body.

One of the problems with the legalization of marijuana is that it will become even more available to younger smokers. The same way that the legalization of alcohol makes it easily available to teens.

Other effects of early marijuana use are:

1) Early marijuana users have less white matter in their brains and the total size of the brain is smaller. White matter affects how the brain learns and functions.

2) There are less connections of one brain cell to another resulting in slowing thinking

3) Early use is strongly associated with schizophrenia and other psychotic and anxiety disorders.  It is very difficult to prove that marijuana causes the disorder or just used as self-treatment.

4) Heavy and/or prolonged use leads to lower IQ's and serious memory disorders

There are no controlled studies of the effects of marijuana on children or teens, but studies show that early use is very different from use after age 18 years in its long-term effects.

A final note: smoking marijuana leads to poor driving.  Teens drive poorly even when not intoxicated.  Marijuana stays in the urine for up to 3 weeks.  If your teen has an accident (very common) and has marijuana in the urine, he or she may be convicted of driving while intoxicated whether they were intoxicated or not.

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