Table 3.
Within- and between-family unstandardized regression coefficients for the association between cannabis use variables with intelligence and EF
| Dependent (Cognitive) and Independent (Cannabis) Variables |
Total Within- Family Effect |
MZ Within- Family Effect |
DZ Within- Family Effect |
Between- Family Effect |
|---|---|---|---|---|
| Model Set 1: Raven (age 17) | ||||
| Age of cannabis initiation (N = 718) | 0.238 | 0.264 | 0.209 | 0.482** |
| Cannabis frequency (age 17; N = 757) | −0.065† | −0.365 | 0.273 | −0.417 |
| CUD (age 17; N = 758) | 1.808† | 0.197 | 3.624* | −5.33** |
| Model Set 2: Raven-S (age 23) | ||||
| Age of cannabis initiation (N = 713) | 0.255 | 0.209 | 0.306 | 0.407** |
| Cannabis frequency (age 17; N = 666) | −0.163† | −0.528* | 0.220 | −0.350 |
| CUD (age 17; N = 667) | −0.949 | −0.669 | −1.246 | −2.309 |
| Cannabis frequency (age 23; N = 710) | −0.159 | −0.075 | −0.250 | −0.342* |
| CUD (age 23; N = 698) | 0.357 | −0.547 | 1.341 | −2.543 |
| Model Set 3: WAIS (age 17) | ||||
| Age of cannabis initiation (N = 720) | 0.039 | 0.023 | 0.057 | 0.149* |
| Cannabis frequency (age 17; N = 759) | −0.031 | −0.020 | −0.043 | −0.075 |
| CUD (age 17; N = 760) | 0.091 | −0.248 | 0.471 | −1.012 |
| Model Set 4: Common EF (age 17) | ||||
| Age of cannabis initiation (N = 706) | 0.002 | 0.010 | −0.006 | 0.019* |
| Cannabis frequency (age 17; N = 751) | −0.019 | −0.016 | −0.022 | −0.003 |
| CUD (age 17; N = 751) | −0.136† | 0.009 | −0.297 | −0.189 |
| Model Set 5: Common EF (age 23) | ||||
| Age of cannabis initiation (N = 717) | −0.009 | 0.000 | −0.019 | 0.012 |
| Cannabis frequency (age 17; N = 670) | −0.023** | −0.023* | −0.023** | −0.001 |
| CUD (age 17; N = 671) | −0.031 | 0.083 | −0.152 | −0.095 |
| Cannabis frequency (age 23; N = 714) | −0.006 | −0.009 | −0.004 | −0.001 |
| CUD (age 23; N = 702) | −0.010 | −0.052 | 0.035 | −0.079 |
| Model Set 6: Updating-Specific (age 17) | ||||
| Age of cannabis initiation (N = 706) | 0.019 | 0.029 | 0.008 | −0.004 |
| Cannabis frequency (age 17; N = 751) | −0.002 | 0.003 | −0.007 | 0.002 |
| CUD (age 17; N = 751) | −0.056 | −0.011 | −0.106 | 0.102 |
| Model Set 7: Updating-Specific (age 23) | ||||
| Age of cannabis initiation (N = 717) | −0.003 | −0.005 | −0.001 | −0.008 |
| Cannabis frequency (age 17; N = 670) | 0.007 | −0.001 | 0.016 | 0.001 |
| CUD (age 17; N = 671) | −0.007 | −0.032 | 0.018 | 0.105 |
| Cannabis frequency (age 23; N = 714) | −0.005 | −0.002 | −0.008 | 0.001 |
| CUD (age 23; N = 702) | 0.033 | −0.024 | 0.094 | 0.119 |
| Model Set 8: Shifting-Specific (age 17) | ||||
| Age of cannabis initiation (N = 706) | −0.023 | −0.016 | −0.031 | 0.000 |
| Cannabis frequency (age 17; N = 751) | 0.002 | 0.010 | −0.008 | −0.003 |
| CUD (age 17; N = 751) | −0.009 | 0.077 | −0.105 | −0.240 |
| Model Set 9: Shifting-Specific (age 23) | ||||
| Age of cannabis initiation (N = 717) | −0.006 | −0.019 | −0.033 | 0.005 |
| Cannabis frequency (age 17; N = 670) | −0.003 | 0.009 | −0.017 | −0.002 |
| CUD (age 17; N = 671) | 0.079 | 0.152 | 0.001 | −0.225 |
| Cannabis frequency (age 23; N = 714) | −0.004 | −0.009 | 0.002 | −0.002 |
| CUD (age 23; N = 702) | 0.070 | 0.067 | 0.072 | −0.113 |
Note. Each row contains a separate model. All analyses controlled for sex and premorbid IQ. Factors scores were standardized prior to analysis. Raven = Raven Progressive Matrices; Raven-S = Advanced Raven Progressive Matrices Short Form; WAIS = Wechsler Adult Intelligence Scale; Frequency = number of days cannabis was used per month over the past six months; CUD = cannabis use disorder diagnosis (i.e., no use disorder, mild, moderate, or severe).
*
p < .01
**
p < .001.