Psychopharmacology (2011) 215:321–332 Table 1 Mean (SD) difference from placebo and 95% CI for cognitive and psychomotor measures in all treatments after single (s) and multiple (m) doses Mean (SD) Differencea 95% CIa Significance 328 Parameter Word learning task Immediate recall score (number) Delayed recall score (number) Divided attention task Tracking error (mm) Response time (ms) Critical tracking task Critical frequency (rad/s) Stop-signal task Stop reaction time (ms) a Least square mean differences and 95% CIs obtained from mixed model analyses b Statistically significantly different at 5% level Drug/dose PLA (s) ESM 1.5 (s) ESM 4.5 (s) ZOP (s) PLA (m) ESM 1.5 (m) ESM 4.5 (m) PLA (s) ESM 1.5 (s) ESM 4.5 (s) ZOP (s) PLA (m) ESM 1.5 (m) ESM 4.5 (m) PLA (s) ESM 1.5 (s) ESM 4.5 (s) ZOP (s) PLA (m) ESM 1.5 (m) ESM 4.5 (m) PLA (s) ESM 1.5 (s) ESM 4.5 (s) ZOP (s) PLA (m) ESM 1.5 (m) ESM 4.5 (m) PLA (s) ESM 1.5 (s) ESM 4.5 (s) ZOP (s) PLA (m) ESM 1.5 (m) ESM 4.5 (m) PLA (s) ESM 1.5 (s) ESM 4.5 (s) ZOP (s) PLA (m) ESM 1.5 (m) ESM 4.5 (m) N 31 29 29 29 28 30 30 31 29 29 28 28 30 29 31 29 31 29 30 30 30 31 29 31 29 30 30 30 31 30 32 30 30 30 30 31 30 32 30 30 30 30 26.3 (4.8) 24.4 (5.3) 26.6 (5.8) 26.0 (5.1) 27.0 (5.7) 26.7 (6.5) 26.8 (5.9) 9.3 (2.9) 7.8 (3.3) 8.6 (3.6) 8.7 (3.0) 8.9 (3.3) 9.4 (3.5) 9.3 (3.1) 19.9 (3.8) 21.3 (4.2) 21.8 (4.3) 20.1 (4.6) 20.1 (4.5) 21.4 (4.1) 21.1 (4.6) 1770 (246) 1899 (261) 1859 (247) 1833 (205) 1783 (228) 1812 (202) 1811 (211) 3.43 (0.62) 3.36 (0.61) 3.29 (0.68) 3.38 (0.79) 3.41 (0.72) 3.44 (0.62) 3.34 (0.70) 288 (48) 292 (46) 297 (51) 292 (49) 285 (45) 297 (57) 288 (49) −1.7 0.4 −0.1 0.2 −0.2 −1.4 −0.7 −0.6 0.7 0.6 1.4 2.0 0.2 1.2 0.9 139 95 62 27 30 −0.10 −0.15 −0.05 0.02 −0.07 4 8 4 13 3 [−3.8, 0.4] [−1.2, 2.1] [−2.0, 1.8] [−2.3, 2.6] [−2.7, 2.3] [−2.5, −0.3] [−1.6, 0.2] [−1.5, 0.3] [−0.4, 1.8] [−0.4, 1.6] [0.6, 2.3] [0.9, 3.1] [−0.9, 1.3] [0.1, 2.2] [−0.1, 2.0] [33, 246] [−3, 192] [−33, 157] [−50, 105] [−49, 109] [−0.22, 0.02] [−0.33, 0.03] [−0.22, 0.12] [−0.12, 0.16] [−0.22, 0.08] [−15, 23] [−13, 30] [−15, 23] [−11, 36] [−18, 24] b b b b b