Table 1. Demographics and drug use of all study subjects.
|
Sample 1 |
Sample 2 |
|||||
|---|---|---|---|---|---|---|
| Test | Cocaine | Control | Test | Cocaine | Control | |
| N=33 | N=20 | N=14 | N=15 | |||
| Gender: male/female | χ2=0.0 | 28/5 | 17/3 | χ2=1.1 | 13/1 | 15/0 |
| Race: African-American/Other | χ2=2.5 | 25/8 | 11/9 | χ2=1.2 | 12/2 | 11/4 |
| Age (years) | t=2.7* | 44.2±6.3 | 39.8±5.0 | t=2.7* | 45.8±8.3 | 38.6±6.1 |
| Education (years) | t=1.9 | 12.8±1.9 | 13.8±1.7 | t=1.9 | 12.9±2.2 | 14.2±1.4 |
| Verbal IQ: Wide Range Achievement Test III—Reading Scale92 | t=0.9 | 94.0±11.9 | 97.4±14.5 | t=1.6 | 95.0±10.6 | 101.2±9.7 |
| Non-verbal IQ: WASI—Matrix Reasoning Scale93 | t=0.8 | 9.9±3.4 | 10.6±2.8 | t=0.5 | 10.6±2.8 | 10.0±3.7 |
| Depression: Beck Depression Inventory II94 | Z=−1.6 | 5.5±4.6 | 3.6±3.6 | Z=−3.1* | 8.0±5.0 | 2.2±4.1 |
| Socioeconomic status: Hollingshead Index | t=1.0 | 29.5±12.5 | 32.7±12.9 | t=0.6 | 36.3±9.8 | 38.7±10.6 |
| Cigarette smokers (current or past/nonsmokers) | χ2=14.2* | 27/6 | 6/14 | χ2=9.9* | 11/3 | 3/12 |
| Daily cigarettes (current smokers: Sample 1: N=23/4; Sample 2: N=10/0) | t=0.1 | 8.7±5.8 | 9.0±6.1 | — | 8.4±4.1 | — |
| Time since last use (within 4 h/>4 h) | χ2=4.6 | 18/5 | 1/3 | — | 2/8 | |
| Age of onset (years) | — | 24.2±5.5 | — | — | 26.6±8.2 | — |
| Duration of use (years) | — | 18.0±6.2 | — | — | 14.5±8.1 | — |
| Current abstinence (days since last use) | — | 157.7±534.9 | — | — | 3.9±6.7 | — |
| Cocaine urine status: positive/negative | — | 20/13 | ||||
| Past month use: days/week | — | 2.6±2.4 | — | — | 2.4±1.8 | — |
| Severity of Dependence Scale (0–15) | — | 6.2±4.0 | — | — | 6.8±2.4 | — |
| Withdrawal symptoms: 18-item CSSA (0–126)95 | — | 14.1±9.4 | — | — | 17.0±7.2 | — |
| Cocaine craving: 5-item Questionnaire (0–45)96 | — | 16.4±12.2 | — | — | 21.8±12.7 | — |
Abbreviations: CSSA, the Cocaine Selective Severity Assessment Scale; WASI, Wechsler Abbreviated Scale of Intelligence.
Note: values are frequencies or means±s.d.; *P<0.05; race: Other (Caucasian, Hispanic or Asian); χ2-tests were used for categorical variables; Mann–Whitney U for all drug-related variables (continuous non-normally distributed variables); and t-tests for continuous, normally distributed variables.