"Associations Between Evolving Cannabis Policies and Cannabis-Related School Discipline Among Secondary School Students in Massachusetts, 2005-2019".

Introduction: The objective of this study was to examine whether cannabis policies - including decriminalization, medical legalization, and recreational legalization among adults are associated with changes in cannabis-related disciplinary incidents (CDIs) in Massachusetts public schools.

Methods: This retrospective cohort study utilized 2005-2019 Department of Elementary and Secondary Education (DESE) data on disciplinary incidents in all public school districts (N = 399). A multilevel time-series model with multiple interruptions was used to examine the relationship between cannabis policy changes and district level CDIs per 1,000 students in MA from 2005-2019.

Results: There were statistically significant increases in CDIs during the decriminalization policy period compared with pre-decriminalization; the CDI incident rate per 1,000 students increased by 34% relative to the time prior (IRR: 1.34 CI: 1.11, 1.60). However, CDIs decreased during the medical and recreational policy periods; the CDI incident rate decreased by 45% during the medical policy period compared with decriminalization (IRR: 0.55, CI: 0.47, 0.65) and by 20% during the recreational policy period (IRR: 0.80, CI: 0.68, 0.94). The average number of CDIs per school district ranged from 4.6 during decriminalization (2008-2011), 4.7 during medical (2012-2015), and 5.1 during recreational legalization (2016-2019).

Conclusion: There was a modest increase in CDIs in schools after decriminalization in 2008. However, as state cannabis legalization policies expanded, the CDI incident rate per 1,000 students decreased. These findings are encouraging and underscore the need for schools to continue to develop and implement alternatives to exclusionary discipline that employ a harm reduction approach.