Jill McGavin: What struck me most in the article (Budney et al., 2007) was the reference to the rise in treatment admissions for primary marijuana dependence in the last 10 years. An increase from 7 to 16 percent of treatment admissions is dramatic. It makes me wonder what the next 10 or 15 years will bring. I’m anxious to go back and review the numbers in our treatment admissions for the past couple of years to see if we’ve already started a shift that has gone undetected.
Dana Mackin: I was relieved to see that Dr. Budney and his coauthors addressed the uniqueness of marijuana addiction. When I first started reading their article, I was resistant to the idea that marijuana causes dependence, because when we think of addiction we think of the extreme and striking consequences of methamphetamine or alcohol abuse. On the other hand, we see the occasional person who has no problem dropping alcohol or methamphetamine, but cannot stop smoking pot.
McGavin: Marijuana dependence is usually a co-occurring addiction and usually not the more dramatic one. I work primarily with veterans. On average, they are in their 50s. About a third are primarily alcohol-dependent, a third primarily cocaine-dependent, and a third primarily heroin-or opioid-dependent. In only a few cases is marijuana a primary dependency.
Christopher Martin: My experience is similar. However, I do see a fair number of patients for whom marijuana abuse is a primary issue. Many of them are young adults who are involved in daily cannabis abuse and are not functioning well. They haven’t moved out of their parents’ homes and are spending a lot of their time alone, playing video games and sitting around the house.
Mackin: Marijuana dependence is definitely an issue in our clients’ lives. Someone in recovery who has a heroin or methamphetamine addiction is much more likely to relapse after using pot or taking a drink. A client of mine said, “You don’t relapse on your drug of choice; you relapse with pot. Smoke a joint, and 3 days later, you’ll have a needle in your arm.” In short, once you cut out your executive decision-making ability, relapse is right around the corner.
Martin: That’s consistent with studies with animal models, which have shown that drugs have cross-priming properties. Animals addicted to one substance, when exposed to another reinforcing drug, will relapse to use of the original substance. All of these drugs have similar effects on the mesolimbic dopamine system and the reward circuitry, and it’s not surprising that one positively reinforcing substance can make it difficult to stay away from another.
McGavin: Also, if you’re hanging on the corner, you’re more likely to be passed something you shouldn’t be using.
Mackin: Right. It puts you back into the environment, and you don’t learn to deal with anxiety or craving for your primary drug without the aid of an external substance. You’re repeating the same behavior with a different substance.