Here is a great article with a practical method of using dark light therapy/ blue light therapy to sort out your circadian rhythm.
Blue Light Blockers: A Behavior Therapy for Mania (psychiatrictimes.com)
It is used primarily for people with bipolar, but if you invest in an eye mask for sleeping and some $10 glasses and wear them for a few hours in the evening you can get your sleeping patterns back in order.
It works for insomniacs and bipolar too.
"You don’t need to be in the hospital to do this therapy. Phelps has had success using it in an outpatient practice, and we have as well. Here’s how you do it.
The original protocol required manic patients to be in either pitch darkness or virtual darkness (that is, with the amber glasses on) for 14 hours, from 6:00 PM to 8:00 AM. It took about a week for the mania to improve, and as it did the protocol was relaxed a bit, from 14 hours per night to 10 hours per night. So instead of putting the glasses on at 6 PM, they’d put them on at 7:00 PM, then 8:00 PM, and for prevention thy would move it to 9 or 10 PM. They don’t wear the glasses while asleep. That’s what the pitch-dark bedroom is for. But they do put them on if they are awake and the lights are on.
And the pitch darkness really does matter. Even light as dim as a nightlight on can interfere with melatonin secretion. In a large epidemiologic study of older adults, sleeping with a night light on doubled the risk of depression over 2 years compared to a pitch-dark bedroom."
" Dark Therapy for Insomnia
KN : Dark therapy improves mania, but what does it do to sleep? We found 3 randomized controlled trials that tested them out in insomnia, and they had a large effect, helping patients stay asleep longer, fall asleep earlier, and deepening sleep quality.10-12 One of them used the blue light blockers as an adjunct to CBT-insomnia, where half the patients had the behavioral therapy with placebo glasses and half used the blue-light blockers. Not only did sleep improve with the blockers, but so did anxiety and depression.10 Another study looked at performance on cognitive tests after wearing the glasses, and that got better as well, probably because the patients were sleeping better.11 In the sleep studies, patients put the glasses on 1.5 to 2 hours before bedtime.
Blue light blockers have been used successfully in jet lag, and they tend to help night owls fall asleep earlier."
" Dark Therapy for Depression
KN : Blue light blockers have a big effect in mania and rapid cycling, and for sleep they deepen sleep quality and turn night owls into morning people. But can they help depression? We know from animal studies and epidemiologic studies that blue light causes depression, but when it comes to clinical studies using blue light blockers to treat depression the results are mixed. In that CBT-insomnia study, they did improve depressive symptoms, but those patients had clinical insomnia, not clinical depression.10 Beyond that, we have only 2 controlled trials, 1 positive, 1 negative. The positive one was small (n = 27) and centered on postpartum depression, where nocturnal awakening is the norm. Women who used blue-light blockers and low-blue light bulbs had greater improvements than those who used placebo glasses and bulbs.13 The negative study was also small (n = 20) and included depressed patients with insomnia. The investigators suspected that the glasses might not have worked because the patients found them uncomfortable and did not wear them as much as they should.14"
If you have depression, insomnia or mania then dark therapy is worth a try and this article is insightful and a must read. 