Table 1.
Demographic characteristics and drug use by study group
| Urine positive cocaine subjects (n = 16) | Urine negative cocaine subjects (n = 26) | Control subjects (n = 23) | |
|---|---|---|---|
| Gender (male/female) | 15/1 | 24/2 | 18/5 |
| Ethnicity (African-American/Caucasian/other) | 11/2/3 | 17/6/3 | 12/10/1 |
| History of cigarette smoking (current or past/never)a | 15/1b | 22/4b | 4/19c,d |
| Daily frequency of smoking (for current smokers; n = 35) | 6.6 ± 5.4 | 6.1 ± 4.7 | 3.3 ± 5.8 |
| Hours since last cigarette (for current smokers; n = 35) | 14.2 ± 16.2 | 24.6 ± 37.3 | 13.8 ± 9.3 |
| Education (years) | 13.0 ± 1.6 | 13.1 ± 2.9 | 13.9 ± 2.2 |
| Age (years)e | 48.0 ± 5.3d | 42.1 ± 9.1c | 42.7 ± 6.3 |
| Socio-economic status | 33.0 ± 9.9 | 33.6 ± 11.1 | 32.0 ± 10.6 |
| Non-verbal intelligence: Wechsler Abbreviated Scale of Intelligence: Matrix Reasoning scaled score | 8.7 ± 3.9 | 10.7 ± 4.5 | 11.3 ± 2.6 |
| California Verbal Learning Test II: total recall (trials 1–5)f,g | 41.4 ± 10.4b | 44.6 ± 8.5 | 51.2 ± 11.0c |
| California Verbal Learning Test II: long delay free recall | 8.2 ± 3.7 | 9.3 ± 3.0 | 10.8 ± 3.5 |
| California Verbal Learning Test II: long delay cued recall | 9.9 ± 3.5 | 10.1 ± 3.0 | 11.8 ± 3.1 |
| California Verbal Learning Test II: recognition hits | 14.5 ± 1.6 | 14.3 ± 1.8 | 14.7 ± 1.6 |
| Symbol Digits Modality Test | 44.4 ± 12.7 | 47.2 ± 10.5 | 47.8 ± 9.4 |
| Self-reported state depressionh | 8.9 ± 7.6b | 8.5 ± 7.6b | 1.5 ± 2.8c,d |
| Age at onset of cocaine use | 28.3 ± 4.2 | 26.0 ± 7.7 | – |
| Duration of use (years) | 18.3 ± 8.0 | 15.1 ± 7.0 | – |
| Frequency of use (days/week): last 30 daysi | 4.0 ± 2.6d | 1.8 ± 2.1c | – |
| Current use in $ per use (min–max, median): last 30 days | 10–175, 50 | 0–600, 0 | – |
| Duration of current abstinence (days) (min–max, median)j | 0–4, 2.5d | 4–1825, 31c | – |
| Total score on the Cocaine Selective Severity Assessment Scale (measure of withdrawal symptoms) (0–126) | 14.7 ± 8.4 | 17.1 ± 11.5 | – |
| Severity of Dependence Scale (0–15) | 8.3 ± 8.7 | 8.5 ± 3.4 | – |
| Cocaine Craving Questionnaire (0–45) | 18.7 ± 14.3 | 10.6 ± 9.8 | – |
M ± SD.
a χ2 = 32.3, df = 2, n = 65, P < 0.01.
b Mean value significantly differs from that of controls.
c Mean value significantly differs from that of urine positive cocaine subjects.
d Mean value significantly differs from that of urine negative cocaine subjects.
e F = 3.6, df = 2,62, P < 0.05.
f F = 4.9, df = 2,60, P < 0.05.
g We recently reported that urine positive cocaine subjects perform better than urine negative cocaine subjects on selected neuropsychological tests that included learning, memory, and executive functioning (Woicik et al., 2009). We attribute these differences in results to sampling issues, particularly as they pertain to the inclusion of treatment-seeking individuals in the current but not prior study.
h Kruskal–Wallis H = 22.1, P < 0.001.
i t = 3.8, df = 40, P < 0.001.
j Mann–Whitney U-test, Z = −5.0, P < 0.001.