TABLE 1.
Sample characteristics for each group.
|
Sample characteristics
| ||||||
| Demographics | Healthy controls (n = 32) | Drug dependent (n = 36) | Group comparisonsa | PD (n = 17) | AO (n = 19) | Group comparisonsb |
| Age (years; mean, SD) | 41.9 ± 8.8 | 43.1 ± 8.6 | t(66) = –0.586, p = 0.560 | 41.1 ± 7.9 | 44.9 ± 8.9 | F(2,67) = 1.032, p = 0.362 |
| Age range (years) | 25–64 | 30–60 | 30–58 | 30–60 | ||
| Gender ratio (M:F,%) | 25:7, 78 | 27:9, 75 | χ2(1) = 0.092, p = 0.762 | 12:5, 71 | 15:4, 79 | χ2(2) = 0.44, p = 0.802 |
| Site of scan (Imperial:Camb:Man) | 11:12:9 | 19:10:7 | χ2(2) = 2.34, p = 0.311 | 10:4:3 | 9:6:4 | χ2(4) = 2.83, p = 0.587 |
| Years of education (median, IQR) | 12.5 ± 5.0 | 11.0 ± 1.0 | U = 394.0, p = 0.015 | 11.0 ± 1.0 | 11.0 ± 2.0 |
H(2) = 8.275, p = 0.016 *HC > PD |
| Drug and Alcohol Measures | ||||||
| Lifetime alcohol dependence n (%) | 0 | 36 (100) | 17 (100) | 19 (100) | ||
| Lifetime cocaine dependence n (%) | 0 | 17(47.2) | 17 (100) | 0 | ||
| Lifetime opiate dependence n (%) | 0 | 10 (27.8) | 10 (59) | 0 | ||
| Lifetime nicotine dependence n (%) | 20 (63) | 32 (89) | χ2(1) = 6.56, p = 0.010 | 16 (94) | 16 (84) | χ2(2) = 7.05, p = 0.030 |
| Current smokers n, (%) | 18 (56.3) | 27 (75) | χ2(1) = 2.66, p = 0.103 | 13 (77) | 14 (74) | χ2(2) = 2.69, p = 0.260 |
| Nicotine exposure (pack/year; median, IQR) | 4.4 ± 22.1 | 22.1 ± 21.3 | U = 812.5, p = 0.004 | 24.0 ± 27.4 | 20.0 ± 8.0 |
H(2) = 8.768, p = 0.012 *PD > HC, *AO > HC |
| Months abstinence (median, IQR) | 9.0 ± 20.9 | 11.0 ± 21.3 | 8.0 ± 20.5 | U = 140.5, p = 0.510 | ||
| Months abstinence (range) | 1–102 | 1–102 | 1–79 | |||
| Mood measures | ||||||
| STAI-T Scores (mean, SD) CTQ Scores (median, IQR) |
28.8 ± 6.5 32.0 ± 7.8 |
42.2 ± 11.8 43.5 ± 28.5 |
t(66) = –5.685, p < 0.001 U = 793.5, p = 0.007 |
43.1 ± 11.1 53.0 ± 26.0 |
41.4 ± 12.7 36.0 ± 18.5 |
F(2,67) = 16.127, p < 0.001 *PD > HC, *AO > HC χ2(2) = 14.319, p < 0.001 *PD > HC, *PD > AO |
| PSS Scores (mean, SD) | 15.3 ± 6.2 | 21.1 ± 7.9 | t(66) = –3.350, p = 0.001 | 23.1 ± 6.1 | 19.3 ± 9.1 |
F(2,67) = 6.989, p = 0.002 *PD > HC |
Data are presented as mean ± standard deviation (SD) for normally distributed data and as median ± interquartile range (IQR) for non-normally distributed data. Chi squared (χ2) tests were used for categorical variables. aTwo-group comparisons were conducted between HC and DD using Student’s t-test (t) or Mann–Whitney-U tests (U) as applicable. bThree-group comparisons were conducted between HC, PD, and AO groups using ANOVA (F) or Kruskall–Wallis tests with Bonferroni post hoc comparisons as applicable, significance level P < 0.05. *Indicates where post hoc testing revealed significant 2-group differences. cIndicates months abstinent from all drugs of dependence. STAI-T, Spielberger Trait Anxiety Index; CTQ, childhood trauma questionnaire; PSS, perceived stress scale.