Hi,
I am a 22 year old male that has suffered from insomnia for roughly 7 years. I have incredible difficulty falling asleep, but never staying asleep for up to 8 hours and waking up at same hour. I have been taking 150 mcg melatonin nightly for two years, after suggestions by studies I found on Pubmed. I recently met with a MD sleep specialist at a research university, who said I probably had true insomnia, due to physiological hyper-arousal in the hour before bedtime. I have tried bright light therapy for 3 months to shift my circadian rhythm upon waking (10000 lux light, 30 min, 1 foot from face), however this was unsuccessful in treating the hyperarousal. Sleep hygiene has been practiced, with no caffeine, no naps, no lights in bedroom, breathing exercises, etc. to no avail.
I specifically brought up the issue of taking 150 mcg melatonin nightly with this MD and asked if it would present problems long term, to which she said no. She said I should keep taking it if its working, although it had been traditionally used short term to shift the circadian clock. 150 mcg melatonin has been excellent at putting me to sleep and making me tired at night. I have read studies confirming the role melatonin may play with T3 and T4 thyroid hormones. My question is, am I putting myself at risk by taking 150 mcg everyday? When I don't take it, I sleep only 4 hours. There exists a plethora of literature about the harms of sleeping this little, including coronary problems and diabetes. I know taking exogenous melatonin may shut off my bodies own production, but why would this matter if I just take 150 mcg nightly for the rest of my life?
I think it is possible I am genetically predisposed to not producing enough melatonin, but this has not been confirmed by experimental data.
I appreciate any second opinions, as this is a tricky situation with true insomnia that differs from the typical patient with a shifted circadian clock.