Table 1.
Demographic and substance use characteristics of participants
| Baseline | 18-month Follow-up | |||
|---|---|---|---|---|
| Controls (n=49) | Substance Users (n=47) | Controls (n=49) | Substance Users (n=47) | |
| M (SD) | M (SD) | M (SD) | M (SD) | |
| Age (baseline: 16 to 19 years)*† | 17.6 (0.8) | 18.0 (0.9) | 19.0 (0.9) | 19.5(0.9) |
| % Male | 73% | 59% | - | - |
| % Caucasian | 65% | 65% | - | - |
| % Family history SUD* | 62% | 87% | - | - |
| % Postpubertal | 33% | 47% | - | - |
| Grade point average*† | 3.4 (0.6) | 3.1 (0.8) | 3.3 (0.5) | 3.0 (0.6)a |
| Household Income | $128K (74K) | $137K (117K) | - | - |
| Vocabulary T-score | 59.7 (9.2) | 56.2 (9.5) | - | - |
| Other risk taking T–score† | 48.7 (9.2) | 51.4 (10.4) | 47.6 (7.5) | 51.8 (9.2) |
| Other risk taking (raw)† | 4.2 (5.3) | 5.8 (6.0) | 5.8 (5.3) | 8.9 (6.7) |
| Spielberger State Anxiety total* | 25.7 (6.5) | 29.7 (8.4) | 25.8 (5.5) | 26.5(6.1) |
| Beck Depression Inventory total | 2.1 (2.6) | 3.4 (4.0) | 2.4 (4.3) | 3.7 (4.7) |
| Lifetime drinking occasions* | 25.5 (37.6) | 233.1 (234.7) | - | - |
| Lifetime marijuana use episodes* | 1.4 (2.4) | 471.0 (357.1) | - | - |
| Lifetime other drug use episodesb* | 0.4 (1.9) | 46.5 (139.8) | - | - |
| Days since last alcohol usec* | 323.4 (408.8) | 48.5 (82.0) | - | - |
| Alcohol use episodes over scan interval † | - | - | 64.6 (90.1) | 212.6 (228.7) |
| Marijuana use episodes over scan interval† | - | - | 31.6 (97.3) | 266.0 (284.9) |
| Days since last marijuana usec* | 385.2 (317.3)d | 77.9 (177.7) | - | - |
| Substance use days past 4 weeksef *† | 0.7 (1.3) | 12.6 (9.4) | 3.5 (5.2) | 13.6 (10.2) |
| Cigarettes smoked, past monthe*† | 0.1 (0.6) | 31.8 (101.0) | 0.2 (0.9) | 53.2 (130.7) |
| Fornix, FAg | 0.50 (0.1) | 0.49 (0.1) | - | - |
| S. Corona Radiata, FAg | 0.42 (0.1) | 0.41 (0.1) | - | - |
| S. Longitudinal Fasciculus, FAg | 0.44 (0.1) | 0.44 (0.1) | - | - |
| Fronto-occipital Fasciculus, FAg | 0.45 (0.1) | 0.45 (0.1) | - | - |
Note.
a
n = 46,
b
Other than marijuana, alcohol, and nicotine,
c
Days prior to DTI scan session,
d
n = 16 controls who had used any marijuana,
e
Reported prior to 28-day abstinence period,
f
Excludes nicotine and caffeine,
g
All fractional anisotropy (FA) values 10 −3
*
Group difference at baseline, p < .05,
†
Group difference at follow-up, p < .05