2.4. Randomization
The patients were randomized into two groups: (1) placebo–melatonin–washout and (2) melatonin–washout–placebo. This division was carried out according to the result of a dice throw. Those who threw a number from 1 to 3 went into group 1, and those who threw numbers from 4 to 6 went into group 2. The project researchers were aware of which patients used vial 1 or 2 in the first and third weeks, but they did not know which vial contained the placebo and which contained melatonin until the data analysis was completed.