TABLE 4.
Overview of means, mean differences and p-values across Verbal Learning Tasks.
| Study | Serotonergic psychedelic | Control | Weight | Mean difference | ||
|---|---|---|---|---|---|---|
| Mean (SD) | N | Mean (SD) | N | |||
| VLT–Long delayed recall (p = 0.94; I2= 43%) | ||||||
| Barbosa et al. (2016)* | 12.58 (2.8) | 29 | 13.0 (2.09) | 27 | 16.5% | −0.42 [−1.71, 0.87] |
| Doering-Silveira et al. (2005a) | 12.4 (1.93) | 40 | 12.93 (1.55) | 40 | 30.9% | −0.53 [−1.30, 0.24] |
| Grob et al. (1996) | 9.53 (2.64) | 15 | 8.41 (1.62) | 15 | 12.2% | 1.12 [−0.45, 2.69] |
| Halpern et al. (2005) | 12.2 (1.4) | 61 | 11.9 (1.9) | 78 | 40.4% | 0.30 [−0.25, 0.85] |
| VLT–Trial 5 (p = 0.68; I2= 69%) | ||||||
| Barbosa et al. (2016)* | 13.17 (2.37) | 29 | 13.44 (1.93) | 27 | 32.3% | −0.33 [−1.03, 0.37] |
| Doering-Silveira et al. (2005b) | 12.9 (1.5) | 40 | 13.23 (1.72) | 40 | 40.8% | −0.27 [−1.40, 0.86] |
| Grob et al. (1996) | 11.21 (1.93) | 15 | 9.5 (2.07) | 15 | 26.8% | 1.71 [0.28, 3.14] |
| VLT–Short recall after interference (p = 0.93; I2= 57%) | ||||||
| Barbosa et al. (2016)* | 12.17 (2.76) | 30 | 12.37 (2.20) | 27 | 31.5% | −0.20 [-1.49, 1.09] |
| Doering-Silveira et al. (2005a) | 12.15 (1.9) | 40 | 12.83 (1.58) | 40 | 45.0% | −0.68 [−1.45, 0.09] |
| Grob et al. (1996) | 9.53 (2.72) | 15 | 8.16 (1.99) | 15 | 23.4% | 1.37 [−0.34, 3.08] |
| VLT–Recognition (p = 0.84; I 2 = 31%) | ||||||
| Barbosa et al. (2016)* | 15.25 (1.03) | 29 | 15.19 (0.96) | 27 | 32.1% | 0.06 [−0.46, 0.58] |
| Doering-Silveira et al. (2005b) | 14.55 (0.82) | 40 | 14.78 (0.62) | 40 | 55.6% | −0.23 [−0.55, 0.09] |
| Grob et al. (1996) | 14.3 (0.72) | 15 | 13.75 (1.76) | 15 | 12.3% | 0.58 [−0.38, 1.54] |
* = Means and standard deviation courtesy of Barbosa et al.; N, sample size; SD, standard deviation; VLT, Verbal Learning Task