All figures display predicted values lines over actual count data points. Appendix Figure 1 shows the number of new MMR patient applications over time. The total number of applications increased almost sixfold from December through January 43, to , Figure 1A highlights an increasing trend in monthly increments of marijuana-related hospital discharges. From through , there was an increase over time as well. Marijuana-related hospital discharges increased 0. Notably, the interaction term in the analysis of hospital discharges was not significant, indicating there was no change in trend corresponding with the data point.
Panel A depicts monthly hospital discharges coded as abuse and dependence over time. The dotted line corresponds to July Figure 1B depicts statewide marijuana-related calls to the Rocky Mountain Poison and Drug Center from through Marijuana exposure calls ranked either third or fourth behind calls related to alcohol, cocaine, and methamphetamine prior to , but after marijuana calls ranked second to alcohol data not shown.
The marijuana calls in , 98 calls in , calls in , and calls in were An association was detected between MMR applications and both hospital discharges coded for abuse and dependence Figure 2C and D. Figure 3E graphically highlights monthly marijuana-related treatment admissions in the Denver metropolitan area. In , marijuana admissions declined by Additionally, Table 1 highlights monthly trends in marijuana treatment admissions over time, where significant decreases of 0. The mean values between time periods were not different.
Adult arrests were relatively constant over time prior to and decreased afterward. These are displayed graphically in Figure 3F and highlighted in Table 1. Marijuana related treatment admissions and arrests. Panel E depicts monthly marijuana treatment admissions over time in the Denver metro area. Panel F depicts annual marijuana related adult arrests over time in the Denver metro area. The dotted line corresponds to July panel E , or the year panel F. This paper presented changes in marijuana-related policy and public health outcomes over the time period of the study. The increases in MMR applicants and decreases in trends of marijuana-related arrests may be a direct result of policy changes.
When taken with changes suggesting a decrease in the perceived risk of marijuana, 2 , 5 , 6 these factors may mark increased use and increased acceptance of marijuana over this time period, and be important components of deleterious public health outcomes. In addition to an increase in prevalence of marijuana use over this timeframe 2 , 6 and increases in marijuana-related fatal motor vehicle crashes previously reported, 13 this study identified increases in hospital discharges, poison center calls, and decreases in treatment entries and arrests in this time period.
These concomitant occurrences suggest important effects that may be related to policy changes. This analysis identified increases in hospital discharges over time that could be indicative of broad regulatory effects. However, there was no strong indication that the timepoint, in particular, marked these changes over time. The interaction term was not significant and therefore suggests these increases had been occurring regardless of policy changes.
However, it is also important to note the linear relationship between MMR applications and hospital discharges. Albeit an imperfect exposure measure, the number of registrants allows an estimate of population based marijuana consumption, and is highly similar to exposure estimates based from counts of dispensed prescriptions used in other work. There are limitations to this analysis, however; specifically, individual-level exposures are unknown and individuals likely diverted marijuana to those without licenses.
Further, a contextual reference is necessary to weigh these findings appropriately from an ecologic perspective. A tax-based comparison with alcohol and hospital discharges compared with discharges for marijuana will allow a population assessment of the relative dangers between the two substances based on the quantity spent.
Although it is likely more individuals consumed alcohol than marijuana, in , alcohol-related hospital discharges were approximately fivefold higher The authors detected changes in poison center calls that may be affected by the time point, after which increases were seen. Poison center call data can be considered as sentinel indicators of deleterious drug-related events because they are sensitive to exposures that do not result in an emergency department visit.
However, they are also strongly predictive of emergency department visits due to prescription drug abuse 14 and of deaths due to methadone exposures. Further, recent reports have identified unique risks with edible marijuana products where dosage confusion and individual pharmacokinetics may lead to detrimental effects. Nationally, in there were 4.www.cantinesanpancrazio.it/components/zapajez/1202-intercettare-chat-whatsapp.php
The Effects of Medical Marijuana Laws on Potency
Given the rates of prescription drug misuse and marijuana use, future investigations should explore polydrug exposures of marijuana and prescription medications. Additionally, drug abuse treatment admissions and arrests for marijuana decreased post policy change. Decreases in arrests may be intuitive, but perhaps decreases in treatment admissions are reflective of a more accepting public opinion of marijuana use, and individuals who may have sought treatment prior to are less inclined to do so now.
On the other hand, this decrease could be indicative of a decrease in arrests and corresponding decreases in mandated treatment. Frequently, nonviolent drug offenders are given the option of drug court where mandated treatment is ubiquitous. The relation of arrests and treatment entries could be important, as a report by Kelly et al.
Given the dramatic decreases reported regarding treatment entry, investigations identifying marijuana abuse behavior that is no longer captured through the justice system are warranted. These investigations will likely inform on public health consequences stemming from a new and potential sizable population needing treatment.
Important limitations of this work need to be considered before broad interpretations are made. All presented data are ecologic in nature, where precise individual-level exposures are unknown. The abrupt change in treatment entrants, arrests, and changes in poison center calls suggests an important role of policy change. Public health interventions, such as educational campaigns, could be utilized to mitigate negative outcomes.
This report, owing to the unique effects over time, can be used as a guide to some of the short-term effects that may be related to marijuana policy changes in other states.
Public Health Effects of Medical Marijuana Legalization in Colorado
The funding source for this research was: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
No financial disclosures were reported by the authors of this paper. National Center for Biotechnology Information , U. Am J Prev Med. Author manuscript; available in PMC Mar 1. Corsi , ScD, 1 and Robert E. Booth , PhD 1. The publisher's final edited version of this article is available at Am J Prev Med. See other articles in PMC that cite the published article. Abstract Introduction The public health consequences of the legalization of marijuana, whether for medical or recreational purposes, are little understood.
Methods This observational, ecologic study used an interrupted time-series analysis to identify changes in public health indicators potentially related to broad policy changes that occurred in Conclusions The abrupt nature of these changes suggests public health effects related to broad policy changes associated with marijuana. Introduction The debate around medical and recreational marijuana has recently taken on new vigor with the enactment of legalization for recreational use in Colorado and Washington , and more recently in Oregon and Alaska Methods Data Sources Various sources of public health data were obtained from collaborators to assess trends over time regarding marijuana use.
Statistical Analysis To analyze effects related to broad policy changes, an interrupted time-series analysis was utilized with July used as a transition point, owing to the aforementioned policy events. Open in a separate window. Boldface indicates statistical significance. Discussion This paper presented changes in marijuana-related policy and public health outcomes over the time period of the study.
Limitations Important limitations of this work need to be considered before broad interpretations are made. Conclusions The abrupt change in treatment entrants, arrests, and changes in poison center calls suggests an important role of policy change. Supplementary Material Click here to view.
Finally, model 5 adds the enforcement measures, which also do little to elaborate the previous model. Still, we note the significant negative effect that increased eradication of indoor grows but not outdoor plots has on marijuana potency during the following year. Cluster robust standard errors are reported in parentheses.
In Table 4 , we extend this fully elaborated model in column 5 of Table 3 by examining the impact of specific medical marijuana supply provisions on potency. Specifically, we investigate various combinations of dispensary and home cultivation regulations although we exclude measures of home cultivation and home supply index from the same model due to collinearity.
The results are generally consistent across models, with legally operating dispensaries associated with significant increases in THC levels of about one percentage point on average in states that permit retail sales. In contrast, states with de facto operating dispensaries show a decrease in average potency, although the effect is insignificant. It may be that the lack of state protection of dispensaries means they have not reached a level of concentration within the state to compete very rigorously with the black market for recreational users.
By comparison, home cultivation appears to increase potency by about one-half to three-quarters of a percentage point on average, and our index of home supply falls in the expected positive direction, but both effects are generally small and insignificant. Overall, these results suggest that the state-level allowances for retail dispensary sales are associated with small but significant increases in the average potency of illicit marijuana.
All models include state and year fixed effects and control variables. We now turn to our analysis examining the mediating effects of contextual market factors on the association between medical marijuana laws and potency. These results are presented in Table 5 , where we examine general medical marijuana laws in Panel A and specific supply provisions in Panel B.
In Panel A, the total effects specification corresponds to our fully elaborated model 5 in Table 3. With the inclusion of the mediating variables measuring aggregate compositional and size characteristics of the marijuana marketplace, we are able to decompose the effects of our focal and rival policy variables on potency into direct and indirect or mediated effects.
In other words, these results offer no evidence of a direct regulatory effect of medical marijuana laws on potency. Instead, consistent with our expectations, we find that medical marijuana laws significantly increase the relative share of sinsemilla available or trading within a state. This compositional shift in state marijuana markets toward boutique or high-end product, in turn, drives the observed increase in cannabis potency.
We are primarily interested in the effects of medical marijuana laws, but it is also instructive to examine outcomes for the rival marijuana decriminalization and enforcement variables. Although we do not consider the effect of marijuana decriminalization to be reliable given the noted lack of policy variation, we do find evidence of complementary mediation where the direct and indirect effects point in the same direction.
However, given that the indirect effect accounts for about two-thirds of the total effect, this result is more consistent with our intervening variable thesis. With respect to our enforcement measures, the observed direct and indirect effects are generally small and insignificant. Still, we find it useful to speculate about the general direction of these effects in order to highlight the uncertainties as well as possibilities for future research.
First, the decomposition of our measure of outdoor eradication into direct and indirect effects suggests there are two causal paths that cancel each other out. That is, the direct effect of outdoor eradication is to reduce potency perhaps by forcing growers to harvest prematurely , but this is counterbalanced by a roughly equivalent indirect effect in the opposite direction perhaps by pressuring growers to move operations indoors. In contrast, the total effect of enforcement activity against indoor grows is to reduce potency, with about half the effect operating directly perhaps by removing high-quality product from the market and the other half indirectly perhaps by opening the market to less experienced growers.
In Panel B, we examine medical marijuana supply mechanisms for legally operating dispensaries and home cultivation i. The effect of home cultivation is more complex and suggests possible inconsistent or competitive mediation MacKinnon, et al. Specifically, as with dispensaries, the significant and positive indirect effect of home cultivation suggests a similar avenue of action on potency through contextual features of the marketplace. Lastly, the effects of the rival independent variables in this mediation model remain consistent with the above interpretation.
A fundamental question that has of yet remained unanswered in the academic literature is whether state medical marijuana laws lead to a rise in the average potency of marijuana available on the market. Indeed, prior research by Pacula et al , which examined the impact of medical marijuana laws on self-reported price paid per gram among the arrestee population in the Arrestee Drug Abuse Monitoring ADAM data, showed that self-reported marijuana prices were higher in states that had adopted medical marijuana laws than those states that did not, which the authors interpreted as evidence of a demand shift.
It is also possible, however, that the rise in price is indicative of the availability of more potent product on the market. Indeed such an interpretation is entirely consistent with journalistic accounts of the impact of these laws on development and diffusion of high-potency cannabis cultivation techniques Downs ; Geluardi ; Rendon, ; West This paper provides a direct assessment of the impact of state medical marijuana laws on the potency of marijuana seized through regular law enforcement activities.
We find evidence that the average potency of marijuana seized by law enforcement increases by a half percentage point on average after legalization of medical marijuana, although this result was not significant. However, when we examined specific medical marijuana provisions, our results suggested that in states that legally permit dispensaries average potency significantly increases by about one percentage point over time. Future research will need to confirm these findings using additional years of data that include more than just three legally operating dispensary states. While we recognize the potential endogeneity of the aggregate marijuana market measures to enforcement priorities, our mediation analyses examining the mechanisms through which medical marijuana laws influence potency suggest that the impact of these laws occurs predominantly through a compositional shift in the share of the market captured by high-potency sinsemilla.
In other words, rather than influencing marijuana potency through direct regulatory action, these policies primarily affect potency by influencing the types of marijuana sold in a given market in terms of the proportion of high potency versus low potency products. This study has a number of important limitations.
First, the primary source of information on marijuana potency comes from law enforcement data. This is particularly true of states with relatively few potency observations. Moreover, our compositional measures of the aggregate marijuana market are potentially even more susceptible to bias caused by purposeful law enforcement strategies. It would be important to see if future work using data from other sources that is just now coming on line e.
Weedmaps validate our findings here, although we are unaware of any other publicly available source of longitudinal data on marijuana potency capturing both the medical and nonmedical markets. Second, it is very difficult in our data to tease out independent effects of particular elements of the state policies and a broad medical marijuana policy itself, as many of the policies tend to have very similar characteristics e.
Variation in key characteristics stems largely from just a few unique states, and hence results from these analyses may not be fully generalizable. However, state marijuana policies are evolving at a rapid pace, and analysis of just a few years of additional data would remedy some of these concerns. Finally, it should be reiterated that none of the state policies we examined explicitly specified a minimum or maximum potency that could be sold or, for that matter, provide any general guidelines for potency.
To the extent that medical marijuana laws emerge that provide greater specificity regarding the allowable amount of THC in medical-grade marijuana, it is possible that the mediated effects of this policy could change over time. Additionally, one policy innovation not addressed by this study that merits further examination is the legalization of recreational marijuana, which has already occurred in Washington and Colorado, and which may spread to other states. Recreational legalization carries the potential to exert more profound effects on potency than medical legalization.
For example, the structure of the Colorado law, which limits legal possession to relatively small quantities, might encourage production of higher potency strains. More generally, opening a licit recreational market might change the user base in ways that affect demand for different types of marijuana. It remains to be seen how these broader policies of legalization will affect potency.
Should the findings from this study be replicated, the results have very important implications for policymakers and those in the scientific community trying to interpret the literature of the effects of MMLs on marijuana use. In particular, even if medical marijuana policies do not lead to an increase in the prevalence of marijuana use, it is important to understand the extent to which greater availability of higher potency marijuana increases the risk of negative outcomes among the current stock of users, such as drugged driving, drug-induced psychoses, and other harmful public health outcomes.
Research is also needed to understand the practical significance of, say, a one, two, or five percentage point increase in average THC content. By the same token, it is also critical to develop a broader understanding of how changes in the cannabinoid profile of recreationally available marijuana, such as the ratio of CBD cannabidiol to THC, may attenuate the unintended negative effects of marijuana use Deiana, In short, future work should reconsider the impact of MMLs on health outcomes in light of dramatic shifts in both marijuana potency and the medical marijuana policy environment. We appreciate helpful comments on earlier versions of this work from David Powell, as well as participants of the American Society on Criminology annual conference and the International Society for the Study of Drug Policy annual conference.
All errors are the authors. The opinions expressed herein represent only those of the authors and not the funding agency or our employers. We also distinguish current medical marijuana laws from the more circumscribed and often unfunded state therapeutic research programs enacted in the s and s that allowed investigational access to marijuana strictly within a clinical research setting.
Since the enactment of these laws falls completely outside our study period , we do not address them further here. However, see Caulkins, Lee and Kasunic for a discussion of the general policy implications and consequences of these measures. While California is widely recognized as having a decriminalization statute in , the actual removal of the criminal status of the offense did not occur until In addition, although they fall outside the study period, Connecticut , Rhode Island , and Vermont have recently decriminalized marijuana.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. National Center for Biotechnology Information , U.
Int J Drug Policy. Author manuscript; available in PMC Mar 1. The publisher's final edited version of this article is available at Int J Drug Policy. See other articles in PMC that cite the published article. Abstract Background Marijuana potency has risen dramatically over the past two decades. Results We found evidence that potency increased by a half percentage point on average after legalization of medical marijuana, although this result was not significant.
Conclusion Our findings have important implications for policymakers and those in the scientific community trying to understand the extent to which greater availability of higher potency marijuana increases the risk of negative public health outcomes, such as drugged driving and drug-induced psychoses. Introduction Marijuana cannabis is the most widely used illicit substance in the United States, with about State Marijuana Policies, Markets, and Potency Marijuana is not a uniform product, varying considerably by strain indica, sativa, hybrid , cultivation technique hemp, sinsemilla, hydroponic , and manner of processing herb, resin, oil.
The Effects of Medical Marijuana Laws on Potency
Medical Marijuana Laws As of mid, twenty states including the District of Columbia have adopted laws affording qualifying patients the right to possess and use marijuana for medical purposes without the threat of state prosecution and punishment. Marijuana Decriminalization Policies As of mid, sixteen states have formally decriminalized marijuana by removing penalties for possessing small amounts of marijuana intended for personal use.
An Intervening Variable Hypothesis While the above discussion illustrates that the mix of state marijuana policies governing medical use, decriminalization, and enforcement can seemingly influence potency in a number of cross-cutting ways, it is important to reiterate that none of these laws and policies directly control or place limits on potency. Methods Data The measures for this study come from several data sources.
Table 1 State Medical Marijuana Laws, Open in a separate window. Note that this table does not reflect MML statutes or other legal changes that came into effect after , including new laws in Arizona, Connecticut, Delaware, District of Columbia, Massachusetts, and New Jersey. Empirical Approach Our analysis proceeds in several stages. The basic specification of our differences-in-differences regression model is as follows: Results Table 2 presents descriptive statistics for the sample, stratified by MML status at the state-year level.
Table 2 Descriptive Statistics, Variables 1 2 3 4 5 Medical Marijuana Law 3. Variables 1 2 3 4 5 Legally Operating Dispensaries 0. Discussion A fundamental question that has of yet remained unanswered in the academic literature is whether state medical marijuana laws lead to a rise in the average potency of marijuana available on the market. Footnotes 1 We include Maryland in this group, a state that provides only an affirmative defense for possession of medical marijuana but does not permit home cultivation or regulate other sources of supply.
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Related Medical Marijuana: Changing Times II
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