With the implementation of regulatory frameworks for recreational cannabis in Colorado, Washington and the pending introduction in Uruguay, one of the key issues that has arisen is how to control consumption. Professor Mark Kleiman propounds an interesting theory of how this could be experimented with in the future.

Washington and Colorado, who both began recreational sales this year, have no set monthly quota that marijuana buyers cannot exceed. Instead, both states have set limits on the amount that can be purchased at any one time at 28 grams. Conversely Uruguay, whose law is slated to come into force later this year or at the beginning of 2015, has set a monthly purchase limit at 40 grams.

Given the variation on purchase restrictions between models, a key question arises: What is the monthly, or indeed weekly, limit that consumers should be allowed to purchase that will best mitigate habitual use, or the development of chronic problems? Additionally, in the context where anyone over a set age can legally buy recreational marijuana without any maximum limit established by law, can the consumer be expected to self-regulate?

Mark Kleiman, a professor of Public Policy at the UCLA School of Public Affairs, explained in an editorial for the Washington Monthly earlier this year how the so-called “nudge theory” might be applied to cannabis consumption for models with no set upper limit.

First, a brief explanation of the genesis of nudge theory. Described by Richard Thaler and Cass Sunstein in their 2008 book Nudge: Improving Decisions about Health, Wealth and Happiness, the theory is one designed to help people improve their decision making without imposing restrictions. Proposed originally in US behavioral economics, it can be shaped and applied widely for enabling and stimulating positive changes in people based on indirect encouragement and avoiding direct instruction or enforcement; it should be founded on how people actually think and decide instinctively, rather than how leaders and authorities believe people think and decide. Essentially, nudge theory works by determining choices, which may foster helpful decisions either for the individuals who actually take the decision, but ideally for the broader wellbeing of society.

Professor Kleiman, who has advised both local and federal government on crime control and drug policy, opines that “the great policy challenge to cannabis legalization is discouraging problem use”. Indeed, but how? Kleiman states that one such “approach would be to keep consumers mindful of how much they’re actually using, compared to how much they intend to use, with a system of user-chosen monthly purchase quotas.” And then? “A user could set any limit he [/she] wanted to, but once set, that limit would be binding until changed.”

Kleiman’s proposal is based on a quota of THC -- the active chemical in marijuana -- rather than the weight of marijuana purchased given that THC levels vary markedly between different strains and different products. Professor Kleiman acknowledges that some guidance may need to be provided for less frequent users who wouldn’t know what limit to impose, and suggests that a “default option” that is set at an arbitrarily defined middle amount could be offered to buyers.

In practice, of course, this system may not have an impact on all users, as Kleiman notes:

Some users who run out of quota would simply set a higher limit, and do so again when that higher limit didn’t keep pace with their growing appetite for intoxication.

However, a significant number of users may not alter their self-imposed quota, or could instead even lower it upon the realization that they had set the personal threshold too high. These people, Kleiman says, “would be the beneficiaries of this ‘nudge’ toward temperance.”

Of course, whether such a framework would be beneficial in the long run is impossible to predict. Furthermore, it raises the issue of whether people are better positioned to determine what works best for them over the likes of health professionals who could be integral in setting a government-mandated limit.

In reality, there is almost no scope for the introduction of a nudge system in the near future. However, given the ever evolving world of marijuana regulation, that’s not to say it couldn’t be experimented with at some point. As Kleiman concludes: