The youth of America are abusing booze less and weed more, according to a new study that looked at two decades of data on teens and school-aged children who wound up seeking medical care after taking various substances.

Adolescent cannabis abuse has increased by a whopping 245 percent in the US since 2000, the new research finds, with a particularly dramatic rise occuring in just the past few years.

At the same time, rates of alcohol abuse have declined among those aged between 6 and 18 years. Back in 2000, alcohol was in the top spot on the rather worrying list compiled from a US national poisons database, which records information on calls to poison helplines. Now, it sits in third place.

There has been a wave of cannabis decriminalization in the US in recent years: recreational use is now legal in 19 states. While this is only for adults, the researchers say it has made the drug more widely available and changed public perceptions towards it.

"Ethanol abuse cases exceeded the number of marijuana cases every year from 2000 until 2013," says emergency physician and medical toxicologist Adrienne Hughes, from the Oregon Health and Science University. "Since 2014, marijuana exposure cases have exceeded ethanol cases every year, and by a greater amount each year than the prior."

In total, 338,727 cases of intentional misuse and abuse of medicines and illicit and recreational drugs amongst school-aged children were reported between 2000 and 2020. Of these cases, nearly 60 percent involved males, while more than 80 percent occurred in young people aged from 13 to 18.

Almost a third of the cases on file resulted in "worse than minor clinical outcomes" and the data shows 0.1 percent of cases (450 young people) were fatal. Deaths were mostly down to opioid abuse, as well as being more common in males and in older teens aged between 16 and 18.

When it comes to weed in particular, the stats suggest the rise in availability of foods containing cannabis products has played a significant role, with average monthly call rates for edibles increasing more than those for other forms of marijuana use, like smoking.

"These edible and vaping products are often marketed in ways that are attractive to young people, and they are considered more discrete and convenient," says Hughes.

"Compared to smoking cannabis, which typically results in an immediate high, intoxication from edible forms of marijuana usually takes several hours, which may lead some individuals to consume greater amounts and experience unexpected and unpredictable highs."

Of the other drugs mentioned in the study, dextromethorphan (found in cough medicine) was actually the most reported substance misused or abused between 2001 and 2016 – though reported cases peaked in 2006 and has been on the decline ever since.

The misuse of over-the-counter medicines, which are more widely available and easier to access than illicit substances, remains a problem for young people, the researchers report. High levels of oral antihistamine misuse were also recorded across the study period. Intentional misuse and abuse of substances was also significantly less common in children than adolescents.

As with any field of science, the more detailed the data the more targeted the response to it can be. Health professionals and government officials can use the stats to fight to lower substance abuse and misuse among younger people, and to understand the consequences of decisions like the widespread legalization of cannabis use.

"Earlier initiation of substance use is an important predictor of developing a substance use disorder later in life," write Hughes and colleagues in their published paper.

"As such, clinicians who care for children and adolescents should be well-informed about emerging and shifting patterns of drug abuse and misuse to offer early identification and intervention for problematic substance use."

The research has been published in Clinical Toxicology.