Marijuana potency grows, but research lags behind, LI doc says

How would I respond if my daughter asked me how marijuana could affect her if she began using it?

She would probably be disappointed when I told her that in spite of millions of people using the drug and in spite of many people proclaiming an in-depth knowledge of its effects, there is surprisingly little solid medical information available (as a recent review in the New England Journal of Medicine makes clear).

One fact I could tell her for certain is that the drug has become much more potent in the past few years. The illegal growers have selectively bred the more potent plants and the amount of the active ingredient –- known as THC — has increased from about 3 percent to about 15 percent. This means older studies may be of limited relevance to the drug being used today.

I’d also advise her that it could be addicting. Many of her friends may tell her it is not. Yet the most current research shows about 9 percent of users become addicted in the sense that they have difficulty controlling their drug use and will continue using the drug even though it negatively affects their lives.

More and more users are seeking professional help in order to deal with these dependency problems, as many heavy users will experience a withdrawal syndrome, consisting of problems such as irritability, drug craving and anxiety when trying to quit.

A related problem is that marijuana use has been associated with poor school and job performance. This is a complicated area because it is far from certain if the marijuana causes the problems or if people who have problems in these areas turn to marijuana for relief. The brain keeps developing until age 21 or so, so it is not surprising that beginning use in the teenage years increases the risk of these problems.

Driving is another issue that we would have to discuss. By impairing judgment and coordination, driving while under the influence of marijuana would increase her chances of getting into an accident.

“Stoned” drivers represent a challenge for law enforcement because there is no equivalent of a Breathalyzer that can be conveniently used to determine how much drug is present. Blood tests that measure THC are difficult to interpret because one’s level of impairment is not just dependent on the THC level but also on how experienced a user the person is. Urine tests that check for metabolites are available, however, THC is stored in the body’s fat and slowly released. The result is the person can test positive days or even weeks after last using marijuana especially if they are heavy users.

One thing I could not explain to her is the absurd legal status of marijuana. An increasing number of states allow its use. Yet, the federal Drug Enforcement Agency still classifies it (along with heroin and LSD) as “Schedule I,” that is a drug “…with no currently accepted medical use and a high potential for abuse.”

She’ll have to get a lawyer to explain that one; no doctor I know can.

What if she says, “O.K. you’ve told me about these possible problems with marijuana. But you drink alcohol and alcohol kills over 100,000 Americans a year. Maybe I’m better off with pot.” I’m not sure how I would handle that one.

Dr. Stephen Picca of Massapequa is Board Certified in both Internal Medicine and Anesthesiology. He is retired from practice. Questions and comments can be sent to Dr. Picca at health@newsday.com.