Is prolonged use of melatonin supplements safe for a 3-year-old?

Question

Background:

I recently adopted a 3-year-old girl. The first weeks in her new home, bedtimes were understandably difficult. She had a lot of trouble falling asleep, and resisted going to bed.

My wife and I realized that a lot of this probably had to do with anxiety surrounding the sudden life change (she was given little warning or preparation about her move). We tried all kinds of bedtime routines to help her calm down and be able to sleep. Eventually we worked out a system that worked relatively well, and resulted in a minimum of tantrums and resistance.

However, she still couldn't fall asleep. She would lie awake literally for hours. She was calm and mostly non-interactive, but would just lie there staring at the ceiling, or talking softly to her stuffed animals, or playing with her fingers; finding ways to while away the time because she couldn't sleep. When she finally did fall asleep, she would often wake again during the night, and then would have the same trouble falling asleep again, resulting in a severe lack of sleep.

In consultation with her doctor, we began giving her melatonin about 1/2 hour before we put her into bed. We started with 1mg, and then, when that didn't seem to be enough, we upped the dose to 2mg (again, as per her doctor). We have found that it works amazingly well, and gives her the ability to fall asleep quickly and to sleep through the night and feel well-rested in the morning.

We've been doing this for about 2 months now.

There have been a couple of nights where we forgot to give her the melatonin, or just decided to see how she does without it, and it's immediately right back to the hours of non-sleep, so there's little chance that she can sleep well without it, at least in the near future.

In researching melatonin online, it seems that there isn't a lot known about its long-term effects, and some websites warn that using it for children can cause problems for them later in life.

I want my daughter to be able to sleep well, but I also don't want to do anything that may harm her, now or in the future, so I'm a little concerned about continuing to use the melatonin, since it appears she may need it for a while.

Do I need to be concerned about continuing to give her the 2mg of melatonin every night?

Are there long-term effects I should be concerned about?

If it's not recommended, are there alternatives to melatonin that might have a similar effect of helping her to get to sleep and to stay asleep?

Answer 1

Since melatonin is secerned by many glands (pituitary, thyroid, pineal, adrenals, and gonads), it might be a malfunction of one of these. I am not yet a physician, but I suggest you to try to properly address underlying causes. Maybe melatonin supplements are just a palliative which helps controlling symptoms of something else, like an adenosine lack.

That said, let's get to the science:

This study states that, in relation to development delay risks,

[...]Melatonin treatment in children can be sustained over a long period of time without substantial deviation of the development of children with respect to sleep quality, puberty development and mental health scores[...]

So it apparently is safe to use it on a regular basis. Just remember it's not helpful when there are wake-up-in-the-middle-of-the-night problems, which are often not idiopathic, they mean something, be it a psychological, health, or anything-else related issue.

Have a nice day