The magnitude
of improvements do exceed those reported for valerian17
and equal some, but not all, reported outcomes for exogenous
melatonin.18 Neither of these other natural products,
however, is considered effective treatment for insomnia.
There are a number of limitations in this pilot study.
Although we powered the study to detect moderate effects
on the primary outcome variables, the sample size is small.
In addition, there was no polysomnographic assessment of
sleep as either a screening tool or as an outcome. Participants
who were not screened out by subjective report and
structured interviews, but still had apnea, may have gone
unidentified in this study. Between-group differences would
have been mitigated by the crossover design as such participants
would have served as their own controls. Polysomnography
is also considered the gold standard with
respect to the objective measurement of sleep. Although
polysomnography is a standard assessment method in most
pharmaceutical trials, it is rarely achieved in pre–post-
Table 1. Within- and Between-Group Effects of Placebo and Cherry Juice on Sleep and Other Outcomes
Effect size (d) Timegroup
Mean (SD) Within Between F P
Primary outcome
ISI
Baseline 15.5 (2.7)
Placebo 14.9 (3.6) 0.19
Cherry juice 13.2 (2.8)* 0.86 0.55 5.65 .025
SL (minutes)a
Baseline 24.7 (15.1)
Placebo 23.7 (14.8) 0.07
Cherry juice 21.1 (17.1)** 0.23 0.17 1.25 .274
WASO (minutes)
Baseline 78.9 (32.7)
Placebo 79.1 (38.6) -0.01
Cherry juice 62.1 (37.4)** 0.49 0.46 8.56 .007
TST (minutes)a
Baseline 388.3 (48.8)
Placebo 409.2 (43.9)* 0.47
Cherry juice 417.6 (54.2)** 0.59 0.18 0.47 .528
SE
Baseline 79.2 (7.0)
Placebo 81.4 (8.2) 0.30
Cherry juice 82.9 (8.6)* 0.49 0.18 0.88 .355
Secondary outcomes
MFIa
Baseline 49.1 (12.5)
Placebo 44.1 (9.4) 0.47
Cherry juice 46.2 (11.5) 0.25 0.21 NS
BDI
Baseline 8.5 (4.3)
Placebo 6.4 (4.3) 0.50
Cherry juice 7.3 (4.0) 0.26 0.14 NS
BAI
Baseline 6.8 (4.4)
Placebo 5.0 (4.3) 0.42
Cherry juice 5.8 (4.0) 0.24 0.20 NS
d, the measure of effect size (Cohen’s d); BDI, Beck Depression Inventory; BAI, Beck Anxiety Inventory; MFI, Multidimensional Fatigue Inventory; NS, not
significant.
aThese raw data were transformed to normalize data for significance testing.
Within-group pre–post-treatment improvement of *P