Table 1.
Study | Substances | Group 1 | N | Group 2 | N | Estimated Effect Sizea | Significant Group Difference |
---|---|---|---|---|---|---|---|
Alcohol | |||||||
| |||||||
Kirby and Petry 2004 | Opioids, Cocaine, Alcohol | Alcohol | 33 | Heroin | 27 | 0.88 | Yes |
Alcohol | 33 | Cocaine | 41 | 0.66 | No | ||
Moallem and Ray, 2012 | Alcohol, Nicotine | Alcohol + Nicotine | 213 | Nicotine | 67 | 0.16 | No |
Alcohol + Nicotine | 213 | Alcohol | 107 | 0.31 | Yes | ||
Alcohol | 107 | Nicotine | 67 | — | No | ||
Taylor et al. 2016 | Alcohol, Polysubstance | Alcohol | 27 | Polysubstance | 59 | 0.00 | No |
Moody et al. 2016b | Cocaine, Alcohol, Nicotine | Alcohol | 47 | Nicotine | 137 | 0.12 | No |
Alcohol | 47 | Cocaine | 28 | 0.19 | No | ||
| |||||||
Cocaine | |||||||
| |||||||
Bornovalova et al. 2005 | Cocaine, Opioids | Cocaine | 16 | Heroin | 11 | 0.93 | Yes |
García- Rodríguez et al. 2013 | Cocaine, Nicotine | Cocaine | 17 | Nicotine | 30 | 1.18 | Yes |
Cocaine + Nicotine | 30 | Nicotine | 30 | 1.44 | Yes | ||
Cocaine + Nicotine | 30 | Cocaine | 17 | 0.35 | No | ||
Mejía-Cruz et al. 2016 | Cocaine, Marijuana | Cocaine | 77 | Marijuana | 44 | —b | No |
Moody et al. 2016b | Cocaine, Alcohol, Nicotine | Cocaine | 28 | Nicotine | 137 | 0.63 | Yes |
| |||||||
Opioids | |||||||
| |||||||
Kirby and Petry 2004 | Opioids, Cocaine, Alcohol | Heroin | 27 | Cocaine | 41 | 0.20 | No |
Robles et al. 2011 | Opioids | Methadone only | 30 | Methadone + illicit opioids | 30 | <0.30 | No |
Karakula et al. 2016 | Opioids | Heroin | 106 | Prescription- opioids | 33 | 0.49 | Yes |
| |||||||
Polysubstance | |||||||
| |||||||
Polysubstance | Polysubstance | 25 | Nicotine | 20 | <0.18 | No | |
Businelle et al. 2010 | Polysubstance + Nicotine | 36 | Nicotine | 20 | <0.18 | No | |
Polysubstance + Nicotine | 36 | Polysubstance | 25 | <0.18 | No |
Effect size is reported as Cohen's d. If this was not reported, it was calculated by a) means and standard deviations, b) test-statistics and degrees of freedom, or c) conversion from another measure of effect size.
— Indicates lack of information
This study compared nicotine, alcohol, and alcohol + nicotine groups using three different monetary reward magnitudes: small, medium, and large. There was no effect of group on medium or large rewards, but there was an effect of group on the small reward values, such that the alcohol + nicotine group showed steeper delay discounting relative to both the alcohol and nicotine group.