Table 1. Demographic, clinical, and working memory comparisons between groups.
| HC (n=32) | HO (n=19) | CRK (n=26) | df | Statistics | Post-hoc | |
|---|---|---|---|---|---|---|
| Age (years)* | 27.75 (9.69) | 69.79 (4.69) | 27.88 (7.10) | 2, 74 | F = 373.41 | HC, CRK < HO |
| Years of education* | 15.47 (4.69) | 11.05 (3.70) | 7.58 (2.95) | 2, 74 | F = 50.303 | CRK < HO < HC |
| Income (US$/month)† | 1,972.79 (1,869.68) | 2,946.84 (2,593.16) | 678.91 (1,988.78) | 2, 74 | F = 3.391 | CRK < HC < HO |
| Medications | ||||||
| Antipsychotics* | - | 0 | 11 | 1 | χ2 = 26.308 | - |
| Anticonvulsants† | - | 6 | 10 | 1 | χ2 = 5.908 | - |
| Antidepressants | - | 5 | 6 | 1 | χ2 = 2.899 | - |
| Mood stabilizers | - | 4 | 6 | 1 | χ2 = 1.696 | - |
| Working memory | ||||||
| N-back 1 | 8.84 (1.08) | 7.89 (1.15) | 7.54 (2.14) | 2, 72 | F = 1.69 | - |
| N-back 2* | 6.69 (1.90) | 3.68 (2.26) | 2.50 (2.79) | 2, 72 | F = 7.04 | CRK, HO < HC |
| N-back 3* | 5.34 (2.42) | 2.42 (1.15) | 1.15 (1.31) | 2, 72 | F = 18.42 | CRK, HO < HC |
Data presented as mean (standard deviation).
CRK = crack-cocaine dependent users; df = degree of freedom; HC = healthy younger adults; HO = healthy older adults.
Post-hoc analyses were based on Tukey’s test. For working memory variables, results were controlled for years of education, individual income, and medication use.
*
p < 0.001;
†
p < 0.05.