Cannabis as a Substitute Medication for Alcohol?

Materials and Methods

Electronic searches were performed using PubMed, Google Scholar and ISI Web of Knowledge. Articles including 'alcohol' (or 'ethanol') and cannabis [or 'marijuana' or 'Δ⁹-tetrahydrocannabinol (THC)', the predominant psychoactive compound in cannabis] in the title or as a keyword were considered for this review. Only studies with humans were included. Based on the title and in some cases the abstract, articles were considered for inclusion, then read and organized according to each of the seven criteria. For example, articles regarding health economic costs were discussed and cited under Criterion #7 ('should offer significant health economic benefits'). The objective here is not to provide an exhaustive literature review; for example, genetic and neurobiological studies would certainly supplement the studies cited. Instead, the current goal is to present representative behavioral studies as a step toward determining cannabis' feasibility as a substitute for alcohol.

Table 1. Summary of how cannabis satisfies the seven criteria for substitute therapies.
Criterion	Satisfied?	Caveats
1. Reduces alcohol use and related harms	Mixed: Yes: Mikuriya (1970; Mikuriya and Mandel, 2001, 2004), DiNardo and Lemieux (2001), Clements and Daryal (2005), Peters and Hughes (2010), Metrik et al. (2011), Crost and Guerrero (2012) No: Bickel et al. (1995), Pacula (1998), Aharonovich et al. (2005), Moore (2010)	Studies in favor are limited by focus on medical cannabis patients Behavioral economic studies are conducted among individuals without AUD. Aggregate-level studies must be contextualized with individual-level studies
2. Less harmful than alcohol	Yes: Room (2006), Nutt et al. (2007)	But also not harm free (Room, 2006)
3. Misuse is less than that of alcohol	Mixed: Nutt et al. (2007) ranks both psych and physical dependence risks lower. Cannabis use disorders are less prevalent than AUD [US National Institute of Drug Abuse (2013), Hasin et al. (2007), Falk et al. (2008)]	The prevalence of cannabis use disorders among those with AUD is much higher than those without AUD (Stinson et al., 2006)
4. Can substitute for alcohol	Mixed: Yes: Reiman (2000, 2009), Vaillant et al. (1982), Clements and Daryal (2005), Saffer and Chaloupka (1999), Alter et al. (2006), Lucas et al. (2012) No: Bickel et al. (1995), Pacula (1998), Booth and Kirchner (2001), Aharonovich et al. (2005), Midanik et al. (2007), Magill et al. (2009), Moore (2010)	Studies of med cannabis patients are limited by self-report and possible selection bias. Also, none examine (a) prospective shift from drinking to substituting or (b) whether substituting cannabis for alcohol leads to reduced harms or improved quality of life
5. Is safer in overdose than alcohol	Yes: Nutt et al. (2007), SAMHSA (2004)
6. Does not potentiate the effects of alcohol especially if either drug is taken in overdose	Mixed: Some studies have concluded that cannabis potentiates the effects of alcohol, while others report no synergistic or additive effects in terms of impairment Does not potentiate: Liguori et al. (2002), Lenne et al. (2010), Ballard and de Wit (2011) Does potentiate: Chait and Perry (1994), Ramaekers et al. (2000), Bramness et al. (2010), Ramaekers et al. (2011), Ronen (2010), Downey et al. (2013)	Most driving impairment studies have small samples (n < 20) and do not include individuals with AUD In overdose, fatality would be more likely due to alcohol (SAMHSA, 2004)
7. Offers significant health economic benefits	Only if considering aggregate-level costs. However, because these figures apply to the aggregate, they do not necessarily mean that health economic benefits would be seen in individuals (Harwood et al., 1998; Nutt et al., 2007)	Studies of post-substitution drinking patterns and alcohol-related harms and problems are needed, since the health economic benefits can only be calculated relative to these issues

Table 1. Summary of how cannabis satisfies the seven criteria for substitute therapies.

Criterion

Satisfied?

Caveats

1. Reduces alcohol use and related harms

Mixed:
Yes: Mikuriya (1970; Mikuriya and Mandel, 2001, 2004), DiNardo and Lemieux (2001), Clements and Daryal (2005), Peters and Hughes (2010), Metrik et al. (2011), Crost and Guerrero (2012)
No: Bickel et al. (1995), Pacula (1998), Aharonovich et al. (2005), Moore (2010)

Studies in favor are limited by focus on medical cannabis patients
Behavioral economic studies are conducted among individuals without AUD. Aggregate-level studies must be contextualized with individual-level studies

2. Less harmful than alcohol

Yes: Room (2006), Nutt et al. (2007)

But also not harm free (Room, 2006)

3. Misuse is less than that of alcohol

Mixed: Nutt et al. (2007) ranks both psych and physical dependence risks lower. Cannabis use disorders are less prevalent than AUD [US National Institute of Drug Abuse (2013), Hasin et al. (2007), Falk et al. (2008)]

The prevalence of cannabis use disorders among those with AUD is much higher than those without AUD (Stinson et al., 2006)

4. Can substitute for alcohol

Mixed:
Yes: Reiman (2000, 2009), Vaillant et al. (1982), Clements and Daryal (2005), Saffer and Chaloupka (1999), Alter et al. (2006), Lucas et al. (2012)
No: Bickel et al. (1995), Pacula (1998), Booth and Kirchner (2001), Aharonovich et al. (2005), Midanik et al. (2007), Magill et al. (2009), Moore (2010)

Studies of med cannabis patients are limited by self-report and possible selection bias. Also, none examine (a) prospective shift from drinking to substituting or (b) whether substituting cannabis for alcohol leads to reduced harms or improved quality of life

5. Is safer in overdose than alcohol

Yes: Nutt et al. (2007), SAMHSA (2004)

6. Does not potentiate the effects of alcohol especially if either drug is taken in overdose

Mixed: Some studies have concluded that cannabis potentiates the effects of alcohol, while others report no synergistic or additive effects in terms of impairment
Does not potentiate: Liguori et al. (2002), Lenne et al. (2010), Ballard and de Wit (2011)
Does potentiate: Chait and Perry (1994), Ramaekers et al. (2000), Bramness et al. (2010), Ramaekers et al. (2011), Ronen (2010), Downey et al. (2013)

Most driving impairment studies have small samples (n < 20) and do not include individuals with AUD
In overdose, fatality would be more likely due to alcohol (SAMHSA, 2004)

7. Offers significant health economic benefits

Only if considering aggregate-level costs. However, because these figures apply to the aggregate, they do not necessarily mean that health economic benefits would be seen in individuals (Harwood et al., 1998; Nutt et al., 2007)

Studies of post-substitution drinking patterns and alcohol-related harms and problems are needed, since the health economic benefits can only be calculated relative to these issues