From an article for the SADA newsletter, January 1994
Steve Hayes, Managing Director, Outside In

Dawn Simulation is a technique using a light that comes on very slowly in the early morning, to imitate a natural sunrise. The key research finding is that our 'body clocks' respond to this stimulus by speeding up and reinforcing the 'waking-up process' so that we have more or less woken up even before our eyes open. It is important to note that a light coming on quickly does not have the same effect. We suppose that the explanation goes back to when mankind was evolving, and our systems adapted so that our ancestors woke with the sunrise, which their systems recognised as being a gradual increase of light.

Another way of describing dawn simulation is to say that it regulates our body clocks so, after a few days use, your sleep pattern adapts to the hours you are actually keeping, meaning that you may become more ready to go to sleep earlier as well as get up earlier. In 1996, we added a sunset/twilight go-to-sleep facility which, as Dr Terman found, 'produces a pleasant hypnotic sensation that allowed the patients to fall asleep easier and seemed to help in resolving poor sleep problems.�
Even Teenagers Respond In a trial conducted in 1997 Dr Brainard concluded that 12 out of 12 teenagers found it easier to wake this way, on average twice as easily as usual, and even their parents agreed.

Why should SAD sufferers be interested?
A number of research projects have been undertaken to see whether this might be helpful for SAD sufferers, and the answer is definitely YES. The idea is that part of SAD is connected with the body clock; the body clock is kept in regulation by light, and if the light signals are missing then the body clock loses regulation and so, for instance, it might be telling your system to go to sleep in what is actually the middle of the afternoon because it 'thinks' that it's late at night.

What's the evidence for this? I remember from my childhood hearing on the radio about some experiments in France, when people spent many weeks deep underground with only an intercom to connect them with the outside world, and with no clock or watch. After some days each subject started to get into a new pattern, where they would go to sleep not every 24 hours but, on average, every 26 or 27 hours, although some people's day length revised to as much as 30 hours, with a few experiencing days an hour or two shorter than 24.

You can also think of jetlag, so when you have, say, flown to the USA, one half of you is telling you to sleep because it's after midnight in Britain, but the other half is saying you cannot do this because it's still light.
So light is what regulates our body clocks.

Michael Terman (a famous name in the annals of SAD) and colleagues first tried out Dawn Simulation as a treatment in 1989. They established that at less than 500 lux it produced the drop in melatonin levels that most of us will have read about, with other evidence (looking at how much people move etc) to show that it produced a 'phase advance', ie that the subjects' body clocks were running quicker. And most importantly it showed a marked reduction in SAD symptoms, with 6 of the 8 subjects showing 'full clinical remission'.

The subsequent research was performed by a team headed by David Avery (another well known name in SAD researchers' circles) in Seattle, which is on the north west coast of the USA, nearly in Canada, and a very overcast place for most of the year. These tried a number of different timings and brightnesses, and some of them were restricted to subjects with mild (sub syndromal) SAD. I would summarise these as follows:

1. If the dawn simulation is reasonably realistic it is effective. So a 2 hour time (from minimum light level of under 1 lux to full) was successful, so was 30 minutes, but 10 minutes produced mixed results and 30 seconds was no good. In nature times of 2 hours to 30 minutes are common, but 10 minutes only really applies to the equator, and 30 seconds is not realistic at all. In essence it is a trick which somehow fools the mind into thinking you have experienced a real sunrise, and the body clock is adjusted to be in its early morning state.
2. The light level at full should be a lot less than you get from a light box. The levels of brightness at full varied between 100 lux and 1700 lux. They seem to be equally effective, except, naturally enough, a high brightness 'dawn', over 2 hours tended to wake people up early.
3. The benefits are felt in 1 or 2 days. Whereas light boxes take a week or so.
4. The benefits apply to severe and mild SAD sufferers alike. One large scale experiment selected only mild SAD sufferers, and it showed improvements in drowsiness, energy, mood, social interest, concentration, productivity, quality of awakening, and quality of sleep. For more severe sufferers the symptoms scores reduced from averages of 19 down to averages of 6, which is the same general improvement as you would expect from light boxes.
5. It�s nice. The experimenters say that users liked it. I agree with them, it is a better way to wake up, and so do our customers.

A final quote from a paper at the summer 1993 SLTBR (researchers') conference: "because dawn simulation occurs during sleep it is very convenient unlike conventional bright light therapy. This convenience is likely to result in a higher degree of compliance than with bright light therapy (ie you are more likely to be dutiful about doing it every day). Dawn Simulation produces a degree of improvement similar to that seen in previous studies with light boxes."

What does Norman Rosenthal say? From his new book: "I personally use a dawn simulator each day and find that it really helps me to wake up in the morning .... I take it along with me whenever I travel during the winter months."

Outside In developed the �Natural Alarm Clock�, the world's first fully integrated dawn simulator, and the current Lumie Bodyclock range is based on this original model. For new users, who are often anxious that it might not wake them up, it includes an audible alarm after the light has reached full brightness, although most people find that they are fully awake just in time to prevent the beeper sounding. The new Lumie Bodyclocks also have a light with a built-in dimmer, so they also make lovely bedside lights as well as providing the gentle dawn simulation.

TI Dawn simulation treatment for Winter Depression
AU Avery D.
SO SLTBR Abstracts. 1993 June
AB Reviewing four previous studies the author states that the degree of improvement with dawn simulation is similar to that seen in previous studies of bright light boxes.

TI Dawn simulation in teenage children
AU Brainard G.
SO In Press
AB 80% or more of the subjects who used the (original Bodyclock) and their parents found ease of waking superior (twice as easy as usual) and preferred it to other methods of awakening. Since the clock is a .. novel technology placebo effect could not be ruled out.

TI A controlled study of dawn simulation in subsyndromal winter depression
AU Norden MJ, Avery DH.
SO Acta Psychiatr Scand. 1993 July;88(1):67-71
AB Dawn simulation was well tolerated and resulted in marked improvement in a group of subsyndromal SAD subjects. Both the rapid (placebo) and slow conditions were associated with an improvement over baseline but there was a significant dose response effect favouring the longer dawn signal.

TI Dawn simulation vs. lightbox treatment in SAD: a comparative study
AU Lingjaerde O, Foreland AR, Dankertsen J.
SO Acta Psychiatr Scand. 1998 Jul;98(1):73-80
AB 61 outpatients with winter depression were randomised to receive either lightbox treatment with bright light or dawn simulation treatment in their homes. Patients� ratings of improvement at the end of treatment showed a mean of 40% in the dawn simulation group and 57% in the lightbox group.

TI Is dawn simulation effective in ameliorating the difficulty awakening in seasonal affective disorder associated with hypersomnia?
AU Avery DH, Kouri ME, Monaghan K, Bolte MA, Hellekson C, Eder D.
SO J Affect Disord. 2002 May;69(1-3):231-6
AB Compared to a placebo condition, dawn simulation appears effective in decreasing both prospectively assessed morning drowsiness and retrospectively assessed difficulty awakening. The symptom of difficulty awakening is consistent with the phase delay hypothesis of SAD. Assessment of difficulty awakening could prove useful in the evaluation of SAD.

TI Dawn simulation and bright light in the treatment of SAD: a controlled study
AU Avery DH, Eder DN, Bolte MA, Hellekson CJ, Dunner DL, Vitiello MV, Prinz PN.
SO Biol Psychiatry. 2001 Aug 1;50(3):205-16
AB Dawn simulation was associated with greater remission and response rates compared to the placebo and compared to bright light therapy. The hours of sunshine during the week before each assessment were associated with a positive clinical response.