One in nine US cannabis users over 65 meets criteria for cannabis use disorder

The 1-in-100 figure is simple multiplication: 11.4 percent of the 8.9 percent who used cannabis comes to about 1.0 percent of all adults 65 and older ^[19]. Severity cuts it further. Of those meeting the criteria, 76 percent had mild disorder, 20.1 percent moderate and 3.9 percent severe ^[5]. Moderate or severe disorder therefore affects about 0.24 percent of older Americans, roughly one in 400 ^[20].

The survey tells you who has the disorder. It says less about why. The criterion reported most often was spending time obtaining, using and recovering from cannabis, cited by 74.4 percent of those with the disorder ^[7]. Craving followed at 67.5 percent and tolerance at 48.3 percent ^[8]. Someone who uses on 300 or more days a year spends a lot of time on the drug almost by definition. I think part of the link to near-daily use comes from the criteria themselves ^[6].

Smoking was the most common route, reported by 65.8 percent of past-year users, ahead of eating or drinking cannabis products at 40.5 percent and vaping at 15.4 percent ^[14]. Smoking was also strongly associated with the disorder. So were past-year mental illness, tobacco use and use of other drugs ^[10]. These are associations in survey data. They cannot say whether smoking heavily produces the disorder or whether people with those other problems were more likely to smoke in the first place.

The subgroups are small. If the weighted 8.9 percent roughly matches the raw sample, about 1,900 of the 21,189 respondents were users and about 215 met the criteria ^[22]. Survey weighting means the true unweighted counts could be higher or lower.

Older adults may be more exposed to harm from the same amount of use, because of age-related changes in the body and higher rates of chronic disease and prescription drug use, according to the university's release ^[12]. Earlier studies have tied cannabis use in older adults to cognitive impairment, falls, cannabis poisoning and cannabis-related emergency visits ^[11]. "While there is a lot of attention on how cannabis may help common chronic symptoms older adults experience or the possible acute adverse effects in this population, less focus has been on cannabis use disorder," said Benjamin Han, an assistant professor at UC San Diego School of Medicine and the study's lead author ^[17][16]. "It is important to recognize that any psychoactive substance, including cannabis, can lead to a harmful pattern of use, including among older adults," he said ^[18].

The paper appeared in Addiction on Sept. 28 ^[4]. The university's summary says the findings highlight the importance of screening older adults for unhealthy cannabis use and discussing it as part of routine care ^[13]. I think the data support that much: ask every older patient about use, then run the disorder criteria on those who say yes. The researchers see the mostly mild cases as a chance for early intervention ^[9]. The study does not test whether screening or brief intervention changes anything for older users. Because it pools four survey years, it also cannot show the rising use the release describes ^[21].