In the weeds: a baseline view of cannabis use among legalizing states and their neighbours (2016)

Aims: To describe patterns of cannabis use, the degree of overlap between medicinal and recreational users, and their differential use patterns, modes of consumption and sources of cannabis.
Design: An ongoing probability-based internet panel maintained by the market research firm GfK Group.
Setting: Households in Colorado, Washington, Oregon and New Mexico, USA.
Participants: A total of 2009 individuals from Washington (n = 787), Oregon (n = 506), Colorado (n = 503) and New Mexico (n = 213). Post stratification sampling weights were provided so that estimates could be made representative of the household population in each of these states. Respondents were aged between 18 and 91 years, with a mean age of 53 years.
Methods: We compare patterns of cannabis consumption for medicinal and recreational users as well as simultaneous use of alcohol and cannabis. We also examine the extent to which patterns of use differ across states that chose to legalize (Washington and Colorado) and those that did not (New Mexico and Oregon).
Findings: Rates of life-time medical cannabis use are similar in Colorado and Washington (8.8% and 8.2%) but lower in Oregon and New Mexico (6.5% and 1%). Recreational use is considerably higher than medical use across all states (41%), but highest in Oregon and Washington. Approximately 86% of people who report ever using cannabis for medicinal purposes also use it recreationally. Medical users are more likely to vaporize and consume edibles and report a higher amount (in grams) consumed, and spend more money per month than recreational users. Individuals who use cannabis do not commonly use it with alcohol, irrespective of whether they are consuming cannabis recreationally or medically. Fewer than one in five recreational users report simultaneous use of alcohol and cannabis most or all of the time and fewer than 3% of medicinal users report frequent simultaneous use of alcohol and cannabis.
Conclusions: In the United States, the degree of overlap between medicinal and recreational cannabis users is 86%. Medicinal and recreational cannabis users favor different modes and amounts of consumption. Only a small proportion (12%) of cannabis users usually consume cannabis and alcohol simultaneously, while concurrent use is common among recreational users.