Experts warn sleep-aid use in America is 'out of control' and taking more than 5mg a night over a sustained period could cause cognitive damage

Sustained use of strong melatonin could lead to an unknown array of serious health issues including grave cognitive decline and psychiatric problems in the long-term, experts warn.

More than two percent of American adults now use melatonin regularly, a five-fold increase in the past 20 years. The sleep-aid hasn't been used en masse for long enough for it's real-life effects to be studied, but the NIH has said it fears long-term use could cause cognitive damage such as dementia.

In a new report published in the journal JAMA, sleep and psychiatric experts warned that Americans 'self-medicating' with high doses over a long-term period are putting themselves at risk of short-term side-effects including fatigue, dizziness and headaches - and more serious health consequences in the long-term, especially if taken in conjunction with other medications.

Many of those taking melatonin regularly are consuming it in doses higher than the maximum recommended five milligrams a night and are doing so on a regular basis.