Table 5

Trouble concentrating or thinking clearly at baseline, week 7 and week 14 by group. Mean score derived from the Columbia Scale according to response to the second question, "Over the last 3 days how much have you been bothered by trouble concentrating or thinking clearly? Possible answers and scoring: 1 = not at all, 2 = a little bit, 3 = moderately, 4 = quite a bit, 5 = extremely.

Time point
Control (n = 23)
Intervention (n = 46)


mean score (SD)
mean score (SD)

Baseline
2.5 (1.1)
2.9 (1.2)
Week 7
2.6 (1.1)
1.9 (0.9)
Study end (Week 14)
2.5 (0.9)
1.8 (0.9)

Mills et al. Journal of Circadian Rhythms 2007 5:2   doi:10.1186/1740-3391-5-2