Marijuana plants at a home in Honolulu. (Marina Riker/AP)
Susan H. Greenberg is a writer and editor who teaches journalism at Middlebury College.

My son had recently graduated from high school when I knocked on his bedroom door three summers ago, holding a disposable vape pen filled with cannabis oil — a 21st-century joint. “I know what we can do tonight,” I said slyly, revealing the slender, black cylinder. His father was on a business trip, his two sisters at camp in Connecticut.

“Where’d you get that?” he asked eagerly, without a trace of the wariness or disdain that my overtures usually elicited. 

I told him about my first excursion to a legal weed store, during a weekend girls’ trip to Seattle — my family now lives in Middlebury, Vt. — with the four women whose support and dark humor helped me survive his childhood. I described the tall glass canisters piled with plump buds, the refrigerated case of chocolate edibles, the sales clerk so stoned he couldn’t articulate which variety would help me sleep and which would make me laugh.  

My son became animated and talkative, something I wasn’t used to. We’d been trapped in an ugly cycle of conflict and withdrawal since he was in middle school, our exchanges often either monosyllabic or explosive. Yet there he was, expounding on cannabis strains (sativa energizes you, indica relaxes), the effects of smoking vs. edibles (smoking works faster, the effects of edibles last longer) and how to grow your own. He knew a lot about weed. He’d been smoking since the eighth grade, and it had been the source of many family fights. But not that night.  

We made a plan. I’d pick up Chinese takeout, then we’d have a smoke, eat dinner and watch some good TV, “The West Wing” and “Black Mirror.” 

I wasn’t at all sure this was a good idea. For one thing, in 2016 Vermont was still two years away from legalizing possession for adults over 21. Plenty of my peers thought nothing of enjoying a cocktail with their underage children, but I knew virtually no one who would do the same with a joint. I worried that my son, then 18, would see my participation as an enthusiastic endorsement of a habit I really wished he’d curb, given what I’d read about the damage that heavy cannabis use could do to adolescents’ brain development and working memory.  

But I was desperate to connect with him. He’d been a fussy baby and a mercurial kid, which I could handle, but my patience dwindled as his moodiness persisted into adolescence. I couldn’t understand how someone so bright could be such an erratic student, and I couldn’t accept that this creative and passionate young man was also impulsive and defiant. He resented my watchfulness and my attempts to “fix” him through appointments with tutors, therapists and psychiatrists, reserving special disapproval for our decision to put him on psychotropic medication, starting at age 10, for what doctors diagnosed only as a “mood disorder not otherwise specified.” I saw his point: Who doesn’t suffer from a vague mood disorder at one time or another?  

When he started smoking weed at 13, we didn't permit or condone it, but we couldn't stop it, either. When we confiscated it, he'd get his hands on more; when we grounded him, he'd sneak out, or his friends would sneak in.

Through his teen years, doctors put him on a medley of stimulants, mood stabilizers, anti-depressants and anti-anxiety medications, offering tepid warnings about the risks of their interactions with weed, which he ignored. I thought some worked better than others; my son hated them all, for their side effects and for the implication that there was something wrong with him.  

When he turned 18, he took himself off prescription meds. Cannabis remained his treatment of choice, and he used it daily. It was the only substance that eased his anxiety, leveled his mood and helped him sleep, he said.  

To me, that sounded like addict-speak, a rationalization for a consuming dependency. I encouraged him to consult a psychiatrist and reconsider prescription drugs, which were both better-researched and covered by insurance.  

At the same time, I clearly hadn’t done a great job in making decisions for him, so perhaps I needed to trust him to make his own. By then I’d read more about marijuana and mental health, absorbing complex and sometimes contradictory studies. Some suggested that marijuana might alleviate symptoms of anxiety and depression, others that it might moderately contribute to them, and some found no association at all. Given such mixed evidence, if my 18-year-old son believed that smoking weed helped his anxiety and mood, who was I to judge?  

In the three years since he began treating himself solely with cannabis, I’ve become increasingly comfortable with his choice. Nearly two-thirds of Americans support marijuana legalization, and a growing chorus is hailing its therapeutic benefits. Recreational marijuana use is now legal in 10 states and the District of Columbia, and an additional 23 states allow the sale of medical marijuana. The illnesses approved for treatment with weed (including pain amelioration) vary by state but most often include glaucoma, HIV/AIDS, epilepsy and cancer. However, many lists also cover mental-health disorders; 21 states allow weed for patients suffering from post-traumatic stress disorder, and in 2018 Pennsylvania became the second state, after New Jersey, to approve marijuana as a treatment for opioid addiction.  

What if smoking weed is keeping my son from much greater harm? What if he’s simply an early adopter, and marijuana eventually becomes a widely embraced treatment for the kinds of mood swings and anxieties he experiences? 

Some researchers have urged Americans to hit the brakes, arguing that there is still too much we don’t know about marijuana’s risks, especially given how potent today’s strains are. Ramping up the alarmism, the journalist Alex Berenson, in his book “Tell Your Children: The Truth About Marijuana, Mental Illness, and Violence,” specifically links heavy cannabis use to an increase in psychosis and violent crime. 

But critics have attacked Berenson for conflating correlation and cause and relying too heavily on anecdotal evidence. In 2017, the National Academies of Sciences, Engineering, and Medicine published a comprehensive review of the health effects of cannabis, and its conclusions about the links between marijuana and psychosis were far more nuanced. The report found “moderate evidence” of a statistical association between regular cannabis use and increased symptoms of mania in people diagnosed with bipolar disorder, for example. But the authors stressed that the causal link remained unproved. Among other reasons, it’s hard to disentangle marijuana’s effects from those of alcohol or other drugs people might be taking, including prescription medications. 

The report lamented the shortage of reliable scientific studies on weed and health. The U.S. government could help rectify that by reclassifying marijuana from the Schedule 1 category, meaning it’s considered to have high abuse potential and no medicinal value, to the Schedule 2 group, which acknowledges at least some therapeutic benefits (Adderall and OxyContin are Schedule 2). That would open the door for researchers to conduct more studies. Until that happens, users like my son will continue to serve as self-appointed guinea pigs, tracking weed’s impact on their health and mood 

On that cool evening three summers ago, I decided to set aside my worries. We opened the French doors from the living room to the screened porch, for ventilation. I drew on the vape pen and passed it to him, feeling the illicit thrill of sharing a smoke on the very couch where he and his sisters usually played Xbox. 

We piled our plates with Chinese food, and for 2 1/2 hours, we sat side by side, aligned as conspirators and companions. Watching “The West Wing” sparked conversation about Aaron Sorkin, women in the White House, what makes a good press secretary. We talked, too, about the extent of his weed use, but, for once, I had no trouble keeping my judgment in check. 

He made us milkshakes while I cleared the plates. And in that simple division of labor — routine for other mothers and sons, not so in my family — I saw, with joy and relief, that all was not lost between us. Somewhere beneath the tension and mistrust, we still knew how to care for each other.  

Smoking weed together didn’t create, or even cement, that bond, but for a few hours, it jolted us out of our well-worn roles as antagonists. It put us on equal footing in uncharted terrain and allowed an alternate narrative of our relationship to take root.  

My son is now 21 and living in Pennsylvania, where he has a job, a serious girlfriend and ambitious ideas about how to use mobile devices to monitor (and improve) patients’ health. We have smoked together once or twice since that first time, and though we still have our tense moments, overall we are more relaxed and accepting toward one another. No doubt that’s partly a function of his growing maturity and my willingness to let him choose his own path. But I also believe that our shared experience with weed acted as a salve. Researchers will never prove it, but I’m convinced that, for us, the therapeutic benefits of marijuana include peace and reconciliation. 

Read more from Outlook:

Five myths about socialism

China’s expanding war on Islam: Now they’re coming for the Kazakhs.

We queer clergy begged our fellow Methodists to love us. They voted no.

Follow our updates on Facebook and Twitter