Table 3

 Weighted mean raw differences in effect of Z drugs (treatment) or placebo on insomnia

Weighted mean differences (95% CI)Homogeneity of effect sizes I2 (95% CI)
Within groupsBetween groups
No*TreatmentControlNo*Treatment v controlTreatmentControlTreatment v Control
Primary outcome-sleep latency
PSG14−42 (−60 to −23)−20 (−28 to −11)14−22 (−33.00 to −11.00)96 (94.75 to 97.15)41 (0 to 68.68)94 (91.66 to 95.83)
Subjective2−24.99 (−30.06 to −19.92)−19.43 (−26.61 to −12.25)2−6.90 (−26.00 to 12.37)0 (0 to 100)0 (0 to 100)27 (0 to 72.41)
Secondary outcomes
Wake after sleep onset (PSG)2−20 (−59 to 18)−13 (−34 to 7.89)2−7.14 (−33.00 to 18.23)65 (0 to 91.96)63 (0 to 91.62)0 (0 to 99.98)
No of awakenings (PSG)21.24 (−6.34 to 3.89)−0.94 (−12 to 9.99)2−0.47 (−5.12 to 4.17)94 (81.24 to 98.13)0 (0 to 99.98)0 (0 to 99.90)
No awakenings (subjective)22.88 (−7.15 to 1.39)−1.05 (−4.86 to 2.76)2−1.77 (−4.61 to 1.07)0 (0 to 100)0 (0 to 99.95)0 (0 to 99.81)
Total sleep time (PSG)249.15 (−60 to 16)35.10 (−34 to 10)214.05 (−31.00 to 58.72)63 (0 to 91.45)61 (0 to 91.07)0 (0 to 99.68)
Sleep efficiency (PSG)14.27 (2.01 to 6.52)0 (−2.52 to 2.52)14.47 (2.08 to 6.86)
Total sleep time (subjective)00
Sleep quality (subjective)00
Wake after sleep onset (subjective)00

PSG=polysomnographic.

*No of comparisons.