TY - JOUR
T1 - Recreational cannabis legalization has had limited effects on a wide range of adult psychiatric and psychosocial outcomes
AU - Zellers, Stephanie M.
AU - Ross, J. Megan
AU - Saunders, Gretchen R.B.
AU - Ellingson, Jarrod M.
AU - Walvig, Tasha
AU - Anderson, Jacob E.
AU - Corley, Robin P.
AU - Iacono, William
AU - Hewitt, John K.
AU - Hopfer, Christian J.
AU - Mcgue, Matt K.
AU - Vrieze, Scott
N1 - Publisher Copyright:
© The Author(s), 2023.
PY - 2023/10/5
Y1 - 2023/10/5
N2 - Background The causal impacts of recreational cannabis legalization are not well understood due to the number of potential confounds. We sought to quantify possible causal effects of recreational cannabis legalization on substance use, substance use disorder, and psychosocial functioning, and whether vulnerable individuals are more susceptible to the effects of cannabis legalization than others. Methods We used a longitudinal, co-twin control design in 4043 twins (N = 240 pairs discordant on residence), first assessed in adolescence and now age 24-49, currently residing in states with different cannabis policies (40% resided in a recreationally legal state). We tested the effect of legalization on outcomes of interest and whether legalization interacts with established vulnerability factors (age, sex, or externalizing psychopathology). Results In the co-twin control design accounting for earlier cannabis frequency and alcohol use disorder (AUD) symptoms respectively, the twin living in a recreational state used cannabis on average more often (βw = 0.11, p = 1.3 × 10-3), and had fewer AUD symptoms (βw = -0.11, p = 6.7 × 10-3) than their co-twin living in an non-recreational state. Cannabis legalization was associated with no other adverse outcome in the co-twin design, including cannabis use disorder. No risk factor significantly interacted with legalization status to predict any outcome. Conclusions Recreational legalization was associated with increased cannabis use and decreased AUD symptoms but was not associated with other maladaptations. These effects were maintained within twin pairs discordant for residence. Moreover, vulnerabilities to cannabis use were not exacerbated by the legal cannabis environment. Future research may investigate causal links between cannabis consumption and outcomes.
AB - Background The causal impacts of recreational cannabis legalization are not well understood due to the number of potential confounds. We sought to quantify possible causal effects of recreational cannabis legalization on substance use, substance use disorder, and psychosocial functioning, and whether vulnerable individuals are more susceptible to the effects of cannabis legalization than others. Methods We used a longitudinal, co-twin control design in 4043 twins (N = 240 pairs discordant on residence), first assessed in adolescence and now age 24-49, currently residing in states with different cannabis policies (40% resided in a recreationally legal state). We tested the effect of legalization on outcomes of interest and whether legalization interacts with established vulnerability factors (age, sex, or externalizing psychopathology). Results In the co-twin control design accounting for earlier cannabis frequency and alcohol use disorder (AUD) symptoms respectively, the twin living in a recreational state used cannabis on average more often (βw = 0.11, p = 1.3 × 10-3), and had fewer AUD symptoms (βw = -0.11, p = 6.7 × 10-3) than their co-twin living in an non-recreational state. Cannabis legalization was associated with no other adverse outcome in the co-twin design, including cannabis use disorder. No risk factor significantly interacted with legalization status to predict any outcome. Conclusions Recreational legalization was associated with increased cannabis use and decreased AUD symptoms but was not associated with other maladaptations. These effects were maintained within twin pairs discordant for residence. Moreover, vulnerabilities to cannabis use were not exacerbated by the legal cannabis environment. Future research may investigate causal links between cannabis consumption and outcomes.
KW - Co-twin control
KW - discordant twin
KW - drug abuse
KW - longitudinal
KW - psychopathology
KW - substance use disorder
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U2 - 10.1017/S0033291722003762
DO - 10.1017/S0033291722003762
M3 - Article
C2 - 36601811
AN - SCOPUS:85173051140
SN - 0033-2917
VL - 53
SP - 6481
EP - 6490
JO - Psychological medicine
JF - Psychological medicine
IS - 14
ER -