Dr. Peter Grinspoon is a primary care physician at Massachusetts General Hospital and an instructor at Harvard Medical School who has specialized in cannabis science and education for 25 years. His latest book, “Seeing Through the Smoke: A Cannabis Specialist Untangles the Truth about Marijuana,” was published, not coincidentally, on April 20, 2023.

Grinspoon answered questions about recreational cannabis use, which will become legal in Maryland on July 1.

This interview has been edited for length and clarity.

Baltimore Banner: We already have a medical cannabis program in Maryland. What are the lifestyle benefits for someone using it recreationally — like what can this plant do for people?

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Peter Grinspoon: Well, first of all, you know, this is a heretical topic for doctors to talk about, which is a hangover from the war on drugs. I tweeted something about a year ago, just a study that said people from Spain, people between ages 18 and 30, had better sexual experiences and more orgasms with cannabis than without. And I tweeted just, you know … “science has finally discovered what humanity has known for 5,000 years.”

A funny tweet, and this pediatric psychiatrist tweeted back, “You’re a doctor, for God’s sake, why are you promoting cannabis use?” And I wasn’t promoting cannabis use. I was talking about what are the benefits and I also talked about the harms. But it’s so taboo for doctors to even discuss this.

I mean, the endocannabinoid system is 500 million years old. That’s much older than cannabis or humans. So cannabis sort of bootstraps onto our endocannabinoid system. And something that gives us insight, that makes us horny, that makes us hungry — it’s not hard to imagine how that would be evolutionarily advantageous in the modern world.

The way it affects people is that they just are so much more mindfully in the present and connected with themselves and the world and people around them, that they universally report that they can enjoy sex, music, art, literature, mindfulness, meditation, exercise — all the things that seem to be better if you could truly place yourself in the present.

And then you combine that with the fact that cannabis is known to like, increase your sensitivity: Things look more vivid, they feel more textured, it absolutely dials up all your senses to 11 if not higher, and you know this is a main reason. This and a social connection are very big reasons why people use cannabis.

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Peter Grinspoon M.D.
Dr. Peter Grinspoon with his book, “Seeing Through the Smoke: A Cannabis Specialist Untangles the Truth About Marijuana."

So for someone who’s cannabis naive, and they want to try cannabis for the first time, how should they prepare, and what’s your guidance?

Well, the most important thing by far, and this should be spelled out in capital letters, is start low and go slow. The main way to get into mischief with cannabis to take too big a dose. Many of us have had that experience.

It’s very unpleasant. You don’t die — it’s not like an opiate overdose. But my advice to people … is take your time, use a very small dose, even like a quarter of the lowest [potency] gummy, and then the next night you can take a half of the lowest dose. And then if you’re going to make a mistake … make a mistake that you don’t take quite enough; you’re a little disappointed or bored, no big deal.

Eventually … you can get to the right dose. The one thing you don’t want to do is get a huge dose, particularly of an edible at a dispensary, and take way too much — that’s a guarantee [it] will be an awful experience.

Make sure you don’t have to drive, you don’t have any child care responsibilities, or elderly parent … responsibilities. Ideally, if you really haven’t used it before, have someone with you that’s not using it, just like you do with psychedelics. If you do start to feel anxious or uncomfortable, there’s someone who can kind of calm you down and take care of things.

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I know so many people, even people that have used it a lot in the past, they assume that the cannabis today is the same cannabis being used [when they were] in college. … They’ll take like three bong hits and then I’ll get called over like a doctor. “Can you help this person?” They’re like, you know, really freaking out, and it’s just so much stronger these days. And I think that the harm of that being so much stronger is that it’s easier to overconsume.

So people just need to be gentle and take their time. That would avoid almost all the problems.

What do you consider the safest modes of ingestion for beginners?

Honestly, we don’t recommend smoking. If you take a puff a week it wouldn’t hurt you, but if you smoke five or six times a day, it just can’t be good for your lungs.

Smoking cannabis has never been associated with lung cancer or COPD. It is associated with like irritants, like bronchitis, but you know just the tar, the benzene and the polycyclic aromatic hydrocarbons can’t be good for lungs.

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If you need to inhale it, I’m a fan of the dry herb vaporizers. You grind a little bit up and put it in and heat it up. … hot enough to react to the cannabinoids, but you don’t burn it. You don’t get the combustion product. So that’s a safer way to inhale it.

Edibles are safe if you know your dose and you’re on a stable dose. That’s totally fine. But ... it can be a little bit tricky to figure out your dose because people absorb them very differently and there’s a delay between when you take them and when they act.

I’m a big fan of a sublingual tincture. You you can get preparations with high CBD [a popular and nonintoxicating cannabinoid] and some THC [the primary psychoactive component in cannabis]. You just start with a milligram or two of THC and go up very slowly, one drop or two drops under your tongue. That’s, I think, a very safe and gentle way to get people started on cannabis.

First of all, edibles just have very unpredictable absorption, and they have unpredictable effects on people. People make the rookie mistake of “nothing happened” and half an hour or so [later] they take three more and then they have that horrible experience two hours later when all of the [THC] kicks in.

When you smoke it, it goes directly into your lungs, directly to your brain, you directly get the delta-9 THC. But when you take an edible, it’s absorbed through your intestinal system and it gets processed through the liver and the liver converts the delta-9 … to delta-11. It’s a little bit stronger, and people describe it as a little bit more psychedelic.

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So again, I always advocate start low and go slow, but with edibles particularly start low and go slow because you don’t know how you’re going to absorb it.

Who should avoid cannabis? What are the contraindications?

Well, pregnant [or] breastfeeding [people] definitely should not use. Women who might get pregnant have to be careful, just like women who might get pregnant have to be careful about how much they drink. People with a history of psychosis or family history of psychosis. Now, cannabis does not cause per se schizophrenia. … The rates of schizophrenia have been rock-stable at about 1% of the population. There’s no way it’s causing schizophrenia, but that said, it can help precipitate the onset of schizophrenia earlier.

And for people who have psychosis, it can really destabilize them. So definitely people with a history or a family history of psychosis have to avoid cannabis or use it with extreme, extreme caution and awareness that it could really worsen this life-defining disease that they have.

A question that always comes up with newbies is like, “Oh my god, I took too much of an edible or I smoked those three bong hits. I’m too high. What do I do now?”

Well, most of the time, this can be alleviated by sitting in a quiet room or a quiet space outside, sitting with a friend and just distracting yourself and reminding yourself that you took something. It’s not going to last that long. No permanent damage is going to be done and you’ll be fine in a little while.

Just calm, peace, peaceful empathetic reassurance. Most people get over it and then hopefully learn their lesson and take a smaller dose.

It can be scary if you take way too high dose. … If you truly are having a full-blown panic attack, you might have to go to the emergency room to get some medications to calm down. If you’re having chest pain, or really, really rapid heart rate, which can happen — I mean, cannabis can increase your heart rate. If you take way too big a dose, you’re freaking out and your heart rate’s 180 or you’re having any kind of chest pain or trouble breathing, then you absolutely have to go to the emergency room.

Most of the time, empathic reassurance takes care of it.


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