Table 1.

Effects of Substitution or Complementary Use of Cannabis on Use of Alcohol and Alcohol-Related Consequences, by Sample

Substitution
Clinical or Treatment-Seeking or -Engaged
Alcohol use	Alcohol-related consequences
Self-reported substitution of ALC with CB24
CB use days associated with lower ALC consumption after ALC Tx25
Decreased CB after contingency management Tx for CUD associated with increased ALC use; reinitiated CB associated with decreased ALC use26
Non–Treatment-Seeking
Alcohol use	Alcohol-related consequences
CB abstinence associated with increased ALC use7,8,41,42
THC administration associated with increased ALC use and craving43
Combined ALC and CB associated with lower “want more drug”57
Complementary
Clinical or Treatment-Seeking or -Engaged
Alcohol use	Alcohol-related consequences
CB use after AUD Tx associated with resumed ALC use16	More frequent CB use during AUD Tx associated with increased ALC consequences 1 year after Tx19
CB at AUD Tx entry associated with reduced abstinence17	CB use predicts AUD14,15
Mid-level CB use frequency during/after AUD Tx associated with fewer abstinent days after Tx, higher quantity, and greater frequency18,20
Reduced CB use after CUD Tx associated with reduced ALC use among those with AUD21
Reductions in ALC and CB use among persons in ALC Tx who report heavy drinking and CB use22,23
Non–Treatment-Seeking
Alcohol use	Alcohol-related consequences
Daily CB use associated with more ALC use27,28	CB use associated with increased ALC consequences28,32–34,36
Simultaneous use associated with more ALC use6,10,30	Co-use associated with neurocognitive abnormalities35

Note: ALC, alcohol; AUD, alcohol use disorder; CB, cannabis; CUD, cannabis use disorder; Tx, treatment