When the lights go out at night, how healthy are your Zs?

A red light blinks furiously in the darkness. Its aggressive demands are simple: "Attend to the message or I blink until the battery dies." Meanwhile, a row of green lights flicker on and off, a constant visualisation of the Wi-Fi signal's ebb and flow. The computer's monitor spews a dim light across the room, while its processor works throughout the night, downloading software updates.

This is not the command centre of a spacecraft, but rather, a fairly unremarkable 21st century bedroom: various digital devices recharging, downloading, and alerting, all of them emitting light.

This is a concern because night-time light has recently been associated with increased risks for breast cancer and obesity. One study, published in the Proceedings of the National Academy of Sciences, exposed mice to dim light during the night, or a regular light-dark cycle. The mice all received the same quantities of food, and didn't differ in activity levels. However, the mice in the night-time light condition gained more weight than their counterparts living in the regular light-dark conditions.

As if a link between night-time light and physical health wasn't disconcerting enough, a new study published online in the journal Molecular Psychiatry, also suggests a link between exposure to night-time light and mental health. The study, led by Tracy Bedrosian, a neuroscientist at Ohio State University Medical Centre, exposed hamsters to dim night-time light approximating the amount of light emitted from a computer screen or TV. After a few weeks, the previously fun-loving hamsters began to exhibit behavioural changes similar to those observed in depressed humans; social withdrawal and a diminished appetite for pleasure. Furthermore the hamsters evidenced structural changes in their hippocampi, a brain region also implicated in human depression.

These findings might go some way towards explaining the rising tide of depression (and obesity) over the last 50 years. Our increased exposure to artificial light at night has coincided with rising rates of depression. This also fits with an old idea about mental health and the full moon; an idea that is reflected in the word lunatic (crazy) derived from luna, which is Latin for moon. Psychologists have argued that in pre-industrialised societies, when nights were much darker due to limited artificial lighting, a bright full moon might really prove disruptive to sleep patterns, thereby triggering psychological disorders in the vulnerable.

We have known for decades that anything disruptive to our circadian rhythms (the body clock) can result in episodes of psychological disorder. But the issue of night-time light has become enough of a concern for the American Medical Association (AMA) to publish a public health statement about it. Earlier this year the AMA's Council on Science and Public Health issued a report entitled Light Pollution: Adverse Health Effects of Night-time Lighting. The report recognised that exposure to excessive light at night, including the light from electronic media, can disrupt sleep, especially in children and adolescents.

Furthermore, the report acknowledged that such disruption was linked with the suppression of melatonin, which has many important health implications, including links with cancer, diabetes and obesity.

If the idea of anthropogenic global warming is not enough to make us want to turn out unnecessary lights, then perhaps our own immediate health, or the health of our families will prove sufficient motive. Especially when we consider the UAE is a global leader in the purchase of consumer electronics. Dubai chamber of commerce estimates that $3 billion (Dh11 billion) was spent in 2011 on electronic devices. That's a lot of night-time light sources with the potential to bring about melatonin suppression.

Simple problems, thankfully, often require simple solutions. In the case of the unhappy hamsters, allowing them to go back to regular "lights-out" sleeping arrangements reversed their condition within around two weeks.

Consider the potential benefits of ensuring you sleep in a room where blinking red lights and LCD screens are totally extinguished? See it as the sleep equivalent of eating organic - sleep without additives.

This is, after all, how we used to sleep before electronic media devices began to replace teddy bears as our childhood bedfellows.

Justin Thomas is an assistant psychology professor at Zayed University in Abu Dhabi