25, You Say? Let's Nip That In The Bud

A handful of psychiatrists in Minnestota, where cannabis has not yet been legalized for recreational use (but is currently being considered), is calling for the age limit to be 25 when it is legalized.  They cite anecdotal evidence of young patients with psychosis that they claim is caused by today's high-potency weed.  And here is why they are, in a word, wrong:

1. First of all, these psychoses that they cite are occurring despite recreational cannabis remaining illegal in Minnesota for all ages.  Legalizing it with an utterly unrealistic age limit of 25 will only preserve and entrench the current black market while worsening criminal justice inequities, both age and racial disparities.
2. The brain continues developing well into the 30s and 40s, and the risk period for schizophrenia continues until about 30, so 25 is arbitrary.
3. While excessive cannabis use can be harmful at any age, and starting use before age 18 and especially before 15 is likely more harmful than starting at 18 or older, there is really no clear and convincing evidence that using it at 18-20 is any worse than using at 21-24 or 25+, especially for light or moderate use.  To claim otherwise is unscientific, disingenuous, and really pushes the limits of the precautionary principle.
4. As we have noted many times before, the relationship between cannabis and psychosis is quite complex, and far more nuanced than Reefer Madness.  Though there is likely a tiny, exquisitely vulnerable sliver of the population that should really avoid weed like the plague at any age, that is no reason for blanket bans or restrictions (by age or otherwise) for legal adults.  That would be unscientific and unjust.
5. And finally, if today's high-potency weed is in fact the culprit in an alleged (and far from certain) recent increase in psychosis among young people, the solution is NOT to raise the age limit and force it deeper underground, but to put a cap (say, 10% or 15%) on the potency of THC on legal weed (and perhaps also setting a minimum level of CBD, which counteracts many of the adverse effects of too much THC), and/or taxing it based on THC/CBD levels.  And also warn people who are at increased risk of psychosis as well via honest public education messaging without sensational fearmongering.

There it is.  Problem solved.  No good reason to set the age limit any higher than 18, let alone 25.  Let's nip this ageist idea in the bud, pun intended of course.

UPDATE:  Twenty-One Debunked believes that proper labeling and tax incentives alone will likely be enough to encourage lower THC and higher CBD levels even in the absence of hard THC/CBD limits.  Taxing cannabis at a higher rate base on THC levels (whether proportionally, or perhaps disproportionally when exceeding a specific threshold or for specific product categories) and applying an offsetting tax discount based on CBD levels would do the trick, as the market would adjust accordingly.

Also, getting back to the subject of psychosis in young people, don't forget to take your fish oil.  Yes, you read that right.  Apparently a new study found that there is an inverse correlation between omega-3 fatty acid levels during adolescence and psychosis in young adulthood.  This dovetails nicely with a study from 2010 that found that just 12 weeks of giving fish oil supplements to teens at ultra-high risk of psychosis greatly reduced their risk of developing psychosis a year later compared with those given placebo.