Updates on dark therapy for mania from the 2023 International Bipolar Conference.

Publication Date: 09/11/2023

Duration: 15 minutes, 21 seconds

Transcript: 

Do your patients ever complain that they want to address the root of the problem and not just medicate symptoms? Well today we have an answer. Bipolar disorder is caused by disruptions of circadian rhythms, and dark therapy treats mania by fixing that broken biological clock.

Welcome to the Carlat Psychiatry Podcast, keeping psychiatry honest since 2003. I’m Chris Aiken, the editor in chief of the Carlat Report. And I’m Kellie Newsome, a psychiatric NP and a dedicated reader of every issue.

CHRIS AIKEN: In our last episode we learned that light therapy treats bipolar depression, and that it needs to be dosed in the morning, or at least before 2:00 pm. Today we will look at the converse – dark therapy in the night time, but first a preview of the CME quiz for this episode

1. Light at night is associated with which health risks?

A. Cancer

B. Sleep apnea

C. Urologic disease

D. Arthritis

KELLIE NEWSOME: Let’s recap our recent bipolar upgrades:

1. Screen for bipolar disorder with a tool that looks at signs and symptoms of the illness, like the Rapid Mood Screener or the Bipolarity Index

2. Use more lithium

3. Move lurasidone up in your treatment algorithms now that it’s generic, and keep Robert Post’s three L’s on the tip of your tongue for bipolar depression: Lithium, lamotrigine, and lurasidone.

4. Avoid valproate in women of childbearing age

5. When things go wrong in treatment – even if it’s because your patient is stops taking their meds – assume it is your fault. You haven’t found the meds they want to take.

6. Rate the symptoms at every visit, and find a way to visually track them to find those cyclical patterns that are the heart of bipolar illness.

7. Make it your goal to improve functioning, not just symptom reduction

8. Use light therapy for bipolar depression in the morning or at Mid-day

A key rule with light therapy is this: don’t use the lightbox after 2:00 pm. Evening light will flip their circadian rhythm the wrong way, causing mania, insomnia, and even raising the risk of depression. And that brings us to update #8: Use dark therapy.

CHRIS AIKEN: Dark therapy is the only evidence-based behavioral intervention we know of that treats acute mania. It is the converse of light therapy. The patient stays in a pitch dark room all night long, from 6 pm to 8 am. Why those hours? Those imitate a dark winter night, just as light therapy imitates a summer day at the beach. And it’s got to be pitch dark, just like light therapy has to be 10,000 lux bursting bright. But how do you get the patient to stay in pitch darkness all night long?

You don’t. In the 2000’s, psychiatrist Jim Phelps figured something out. The eyes rely on blue wavelengths of light to set the circadian rhythm. They do so through a special photoreceptors in the eye that is neither rod nor cone – it is, literally, a third eye – melanopsin. Dr. Phelps bought blue light blocking glasses from a local factory store in Oregon – this is a problem for factory workers, by the way – factories have lasers pointing everywhere to help align parts, and the workers wear blue-light blocking safety googles to protect their eyes from this industrial laser tag. He gave them out to his patients with bipolar to wear at night, and they got better.

KELLIE NEWSOME: Dr. Phelps’s work was followed up in 2016 by a controlled trial that tested this approach in people who were hospitalized for acute mania. Half wore the glasses, and half wore a placebo – purple colored shades. Again, they only wore them at 6 pm and through the evening, and they took the glasses off to sleep as long as they slept in a pitch dark room. Shutting your eyes is not enough – the eyelids are designed to let light in so we can wake up in the morning.

After a week, there was a stark difference between the dark therapy group and the placebo, with a daunting effect size of 1.7. And here’s one thing more that Dr. Henriksen shared with us about her trial when she presented her findings at the conference. She also measured sleep with an wrist activity monitor, and surprisingly the glasses did not make people sleep more. The ones in the dark therapy group actually slept a little less, but their sleep got a lot more regular – it was better quality, more consolidated and efficient. Keep that in mind when your patient comes back to you and says, “Yea, I tried the glasses but they didn’t work. I still couldn’t sleep.” You need to warn them that they are not going to make them fall asleep, but they will improve their sleep quality – that’s true when using them for insomnia as well.

CHRIS AIKEN: For insomnia, and for milder hypomania, patients don’t need to be so strict about putting the glasses on at 6 pm. They can get good results by starting this dark therapy routine 2-3 hours, or possibly even 1 hour, before bed. In Dr. H’s study, she gradually eased the routine so that patients were putting them on at 7pm and then 8 pm as their symptoms improved.

Just as with light therapy, you need to make sure they are using the right glasses. We keep a list of pairs that were used in research settings at moodtreatmentcenter.com/products. That page also has handouts for patients on how to use them and how to get their bedroom pitch dark with black out curtains, electrical tape over LED lights, towels under the door, there are even blue-light free night lights if your patient is afraid of the dark. 

KELLIE NEWSOME: Blue light blockers start as low as $10-15 dollars for the factory lenses. I’ll tell patients to start with one of those, and then graduate to the $50-80 pairs at lowbluelights.com if they like them, or if they find the cheap ones uncomfortable to wear. Blue light blockers need to block close to 100% of blue light.

CHRIS AIKEN: We like to stick with the 6 pm to 8 am routine, because we’re shy about upsetting circadian rhythms, but Dr. Henriksen shared that in her experience patients with severe mania get faster reduction by wearing the glasses all day long. As a circadian purist, I found the idea shocking, so I asked her about it. She said there isn’t any research one way or the other, and she wouldn’t want patients to do this for more than a day or two, but on the other hand her patients find the total darkness approach so helpful she’s been unable to stop them – they are doing it on their own.

The most robust evidence for dark therapy is in acute mania, and a poster presentation at the conference backs this point up. They measured light levels in the bedrooms of patients with bipolar disorder, and found a strong correlation between bedroom light and the development of manic symptoms – but not depressive symptoms. Those results differ from other studies, which have found an association between light at night and later depression, but they underscore the strong link with the manic phase.

We don’t have controlled trials of dark therapy in mixed states, but it’s a good guess that it would help given the prominence of manic symptoms there. Likewise, controlled studies for prevention are lacking, but from all we know about bipolar – including the fact that new episodes are often triggered by rapid increases of sunlight in the Springtime – the so-called Solar Flux – we’d guess they have some value for prevention. And you are not drifting too far from the medical mainstream if you recommend your patients to keep wearing them at night. The health effects of light at night are serious enough that the American Medical Association has put out a position statement out on it.

Some patients find no benefit with dark therapy, but many do. They feel calmer at night, less anxious, and have better mood and cognition the next day. Blue light reduction reduces many health risks that are relevant to bipolar disorder, like weight gain, heart disease, cancer, and diabetes. But it’s not part of our culture, and it’s up to us to change that conversation. I’ll show patients a graph of melatonin levels with the lights on compared to the blue light glasses on – reminding them that this treatment has real effects on brain chemistry. “That’s great, Dr Aiken,” they’ll say, “I’ll just take melatonin then.” Not so much. Melatonin is fine to use with dark therapy, and may help insomnia, but the supplement failed to make any difference in several studies of bipolar disorder. I’ll tell them, “Taking over-the-counter melatonin is a bit like going to the gym and expecting to get stronger by touching all the equipment. It’s not about pouring melatonin over your brain that brings the healing – your brain needs to do the work of pumping out its own melatonin, and that’s what the glasses do.”

KELLIE NEWSOME: Long ago in the 1860s, the nursing pioneer Dorthea Dix noted that patients recovered from medical illness faster when they had bright light pouring into their South facing hospital windows. Following that cue, Dr. Henriksen has created an entire psych hospital with strict circadian light and dark controls in Norway. We look forward to hearing more about her outcomes as she compares recovery rates with a traditional ward.  

And now, for the study of the day… Randomized controlled trial to prevent postpartum depressive symptomatology: An infant carrier intervention by Emily Little and colleagues from the Journal of Affective Disorders.

CHRIS AIKEN: As we move into an era where a gaba-ergic controlled substances is viewed as the main escape hatch out of post-partum depression, let’s pause to remember the basics. Social supports, a stable family life, good sleep and nutrition, and opportunities to bond with the new baby all reduce the risk of postpartum depression.

KELLIE NEWSOME: This study tested that last one – opportunities to bond. They used the ErgoBaby Omni 360, one of those close-fitting carriers that hold the infant against the parent’s chest – a fabric swing sometimes called “babywearing,” and they gave them to 50 low-income mothers along with instructions on how to use them. Another 50 in the control group got wait listed – so they knew they’d get an ErgoBaby in another 6 months. The women used the carriers for about 2 hours a day, and after 6 weeks their depression scores were significantly lower than those on the wait list. 

CHRIS AIKEN: It’s a small study, and it’s possible that any intervention would have worked better than a wait-list, but it builds on other findings where steps that improve the mother-child bond, including skin to skin contact, prevent postpartum depression.

KELLIE NEWSOME: Join the conversation and get daily research updates from Dr. Aiken’s Daily Psych feed, now available on Facebook, and as always on LinkedIn, Twitter, and Threads– just search for ChrisAikenMD.

KELLIE NEWSOME: Earn CME for this episode from the link in the show notes, and get $30 off your first year’s subscription to the full journal with the promo code PODCAST. The Carlat Report is one of the few CME publications that depends entirely on subscribers. Thank you for helping us stay free of commercial support. 

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The Carlat CME Institute is accredited by the ACCME to provide continuing medical education for physicians. Carlat CME Institute maintains responsibility for this program and its content. Carlat CME Institute designates this enduring material educational activity for a maximum of one quarter (.25) AMA PRA Category 1 Credits^TM. Physicians or psychologists should claim credit commensurate only with the extent of their participation in the activity.