Figure 1.

(A) Total number of placebo capsules chosen by women and men in the placebo group in months 1, 4, and 12. Total possible choices each month 15 (3 on each of 5 nights). Number chosen increased in months 4 and 12 relative to month 1 (Group × Month interaction p < 0.05) in the placebo group with no gender difference. (B) Total number of placebo and zolpidem capsules chosen by men and women in the zolpidem group in months 1, 4, and 12. After choosing placebo or zolpidem on a given night a total of 3 capsules could be taken on each of 5 nights. No significant month or gender differences were found in the zolpidem group. Pbo, placebo; Zol, zolpidem.