Cannabis lifted mood most when young people felt worst—or best
Young people commonly say they use cannabis to feel better, or to stop feeling bad. Both are true, it turns out, but not evenly. What cannabis did to mood depended almost entirely on how a young person was feeling right before they used.
Eighty-five people aged 15 to 24 who were using cannabis at least twice a week and wanted to cut back carried a handheld device for about a week. It prompted them roughly five times a day to rate how they were feeling, and they also reported just before and just after each time they used. This was before any treatment started, so we were watching ordinary life, not a response to therapy.
Cannabis use was followed by a rise in good feelings—energized, happy, sociable, relaxed—and a drop in bad ones. But the size of the mood lift traced a U-shape. It was largest when someone had felt unusually low for them, and also largest when they had felt unusually good. When mood was around a person's ordinary baseline, using barely moved it.
The pattern for bad feelings depended on how severe someone's cannabis problems were. Among those with more symptoms of cannabis use disorder, using was followed by a drop in negative feelings whether they had felt unusually bad or unusually calm beforehand. Among those with fewer symptoms, cannabis only relieved negative feelings when they were already elevated.
Why it matters
The standard account is that people start using for pleasure and later use mainly to escape discomfort. That's not what we found. The pleasure effect stayed just as strong across the whole range of severity — the relief effect got added on top of it. That's a different picture of how a cannabis problem takes hold, and it suggests treatment has to address both, not assume one has replaced the other.
It also points somewhere clinically useful: the moments when a teen is feeling flat, not just the moments they're distressed, may be when cannabis is most reinforcing.
What this doesn't tell us
Eighty-five people, about a week of data each, and no experiment—we observed what people reported, so we can't say cannabis caused the mood changes, only that they followed use. Everyone here was already trying to cut back, and anyone with a co-occurring psychiatric diagnosis was excluded, which leaves out many young people we see clinically. Participants recorded their own use without any verification, and we didn't know the potency of what they used. Some of the mood swings we measured may simply be ordinary teenage variability rather than anything to do with cannabis.
Emery NN, Carpenter RW, Acuff S., Meisel SN, DeFalco A, Soyster PD, Miranda R. Jr. The effect of cannabis use on the time course of positive and negative affect in the daily life of youth. Psychopharmacology, 2026
