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UMass report: To track marijuana health impact, surveys need better questions

Researchers at the University of Massachusetts say better data on marijuana use in the United States is needed to support critical public health research and response.

In particular, Kimberley Geissler and Jennifer Whitehill cited gaps in data regarding adolescent use. They said that a better overall examination of trends and impact does not need new surveys, but that current surveys can be put to better use by asking better, more specific and detailed questions.

Simple yes-or-no questions don’t provide the depth of information needed to draw informed conclusions, they said.

Eleven states, including Massachusetts, and Washington, D.C., have legalized the adult recreational use of marijuana. About 12 others are actively considering it. Yet understanding the associations between state and federal policy changes and cannabis use remains somewhat elusive, said Geissler and Whitehill, who are assistant professors of health policy and management at UMass Amherst.

Geissler and Whitehill said significant variation in data availability related to cannabis use creates challenges in analysis. These include behaviors and perceptions across and within states and over time, including the availability of pre-legalization versus post-legalization data, they said.

Their report was published in the Journal of the American Medical Association Network Open.

“If we have good statewide data, we can understand the impact of legalization better,” Geissler wrote.

Geissler and Whitehill evaluated the availability of eight key indicators over time: lifetime cannabis use, age of initiation, frequency, location and method of use, source of cannabis, perceptions of cannabis and reason for use. The last category distinguished medical from nonmedical use.

“The most basic of these indicators in thinking about cannabis legalization is, how much do people use cannabis and are people changing the way in which they use – are they using more edibles versus smoking? Are there changes in how often they’re using it?” Geissler wrote.

“One thing that’s important from a public health perspective (is) who is using and how is that changing? For example, are adolescents using cannabis more frequently? We found a lot of gaps for monitoring adolescent use.”

The surveys that go beyond yes-or-no questions provide better data for public health strategies to prevent harmful consequences, Whitehill wrote.

“We may be missing key details that could inform policy and efforts to prevent harm,” said Whitehill, an injury prevention researcher

The researchers said creation of new surveys is unnecessary. They said existing surveys can be modified to ask better questions, which would be especially useful for states that are still compiling data as they consider legalization.