new-born, infant, birth

Bright light therapy is one of the most efficient treatments of depression. Free of side effects and flexible to use, it seems to be great therapy for mums suffering from postpartum depression. But is it?

Light: the ultimate natural antidepressant

Originally, bright light therapy was developed for seasonal affective disorder. Winter depression is not a myth. Our brain activation is naturally increased by light, due to an evolutionary adaptive mechanism that improved our motivation during days and warm summers plentiful of prey to hunt, compared to nights and winters when our ancestors were better off hiding in a corner. Delivering more light therefore means improved neural activity, higher levels of serotonin and dopamine – and less depression. And indeed, it was confirmed by clinical studies that therapy with special dose of bright light is indeed the best way of treating seasonal depressios: a natural remedy as efficient as pills or psychotherapy but cheaper and with no side effects.

Soon after the first triumph, scientists began thinking of treating non-seasonal depressions with light, too. And the initial success was repeated. As you can read in our section on depression in general, bright light therapy is one of the best treatments of depression. Despite being less effective than psychotherapy or medication, its effects are basically for free, compared to costly personal therapy or unhealthy pills, making it the best option for light depressions and effective enhancement of other treatments.

Thanks to its natural mechanism of action, light therapy is indeed perfect for pregnant or breastfeeding women. Its ultimate effects are similar to those of antidepressant medication: while the most popular antidepressants aim to increase serotonin levels in the brain by blocking its re-absorption back to the cells, bright light stimulates production of serotonin by activation of respective brain centers, increasing its levels with no artificial chemistry needed (for more information, check our “science” section. But so far, we are discussing depression not specifically linked to babies being born. Would it also work for the postpartum one?

Is post-partum depression simply a depression?

Responding in one word, the answer is yes. So called “psychiatric Bible”, the basic classification of mental disorders called DSM, does not include post-partum depression as a specific category: rather, it is simply a depression that started after giving birth. Exhaustion and some depressive tendencies are normal for a couple of weeks after delivery. By post-partum depression we mean any depressive feelings starting during pregnancy or soon after the birth, extending for more than that.

And with post-partum depression being just a normal depression developing around giving birth, bright light therapy should be as efficient as in any other depressive disorder. But saying that, we should also mention that every single depressed person is unique and different. And that mums or dads suffering with post-partum depression may slightly differ from those suffering with any other depressive disorder. And that may shuffle the cards a bit.

When we meet a depressed person asking for help, we can never be sure what exactly will help to this individual. That is why we try to group people struggling with depression to categories: to be able to foresee what may be the best option for this or that individual patient. While all depressions share the same mechanism extending from our genes to behaviour of our loved ones, the individual mix of causes slightly vary from one type to another. Which also means that for some types of depression certain treatments might be more effective than others.

Therefore, knowing that light therapy is effective in depression in general means that it should be effective in postpartum gloom as well – but deeper analysis might still reveal that patients with postpartum depression might benefit from it either more or less than the average depressed person. But to start from the beginning: do we know why people are often getting depressed just before or after having a baby?

What is the cause of postpartum depression?

Depression develops when our struggles exceed our abilities to cope with them. Is it that simple? Not at all. Because the weight of a struggle is not measured in inches or pounds, but by our own judgement: the more important we see the struggles, the heavier or larger they are. Plus, our coping ability is not a simple thing – but rather a wide range of various actions of our neurons, our loved ones and ourselves. There are certainly some biological underpinnings, like numbers of different brain cells and synapses and receptors on them. But besides genes, these biological mechanisms are also affected by the whole history of our life, including the prenatal times. And even in any given moment, they heavily depend on how we live: how we think, what we feel, whom we meet… And even on our light exposure.

Having a baby is an endless source of fears and stresses. All the worries about the baby itself and all the related work and errands and expenses before and after the delivery often hide deeper, personal worries, being a good parent, not losing the partner during all the changes in the household, about social life, career and everything else. Making it worse, the stress is affecting both partners. And in addition to all these stresses, the woman is undergoing strong hormonal twists.

While for most of us everything will ultimately calm down with the realization that we are making it, in some people the accumulation of all the fears and stresses might simply be too much. With their coping mechanisms exceeded, they lose their optimism and start seeing threats as bigger than they actually are.

Gradually, a downward, depressive spiral may develop, with the bad feelings reducing person’s joy and interest in normal happy things and activities, which, in turn, further undermines the coping mechanisms and causes even worse feelings. As a cause and effect of this deterioration of joy at the same time, brain and bodily mechanisms gradually change towards the depressive states as well, further affecting our guts, immunity, posture and so on: that is the biological part of depression. And all of them work as self-promoting mechanisms: all those little signs of depression from abrupt response to a spouse, to increased inflammation in our bodies further promote more depression.

Importantly, we do not need to seek the ultimate cause of our depressions. In fact, there is no single cause, only an endless number of circumstances that made this spiral to emerge, ranging from genetical predisposition and memories of some injustice decades ago, to insufficient meal last night or too cold smile of a colleague you accidentally met in a supermarket. We simply need to find any way of cutting the Gordian knot, no matter what originally tied it up.

Luckily, we have several options to contradict depression. Medication may boost the antidepressant molecules in the brain to temporarily restore normal brain activation, hoping that after a while we might be able to keep the balance ourselves with no further pills. Different ways of psychotherapy straighten the deformed thinking and feeling, making the threats look soluble and world liveable again. Finally, bright light promotes brain activation and our motivation to do and enjoy things by exploiting the brain’s reactivity to sunshiny days.

“In non-pregnant women, guidelines propose psychotherapy, antidepressant medication or a combination of both as treatment for depression. However, clinical practice shows limited relevance of these guidelines during pregnancy, as the direct availability of psychotherapists is poor, postponing treatment for several months or more. In pregnancy, the window of opportunity is small and from the perspective of the child postponement is in fact non-treatment,”

scientists explain why we need bright light therapy in pregnant women. But can we its benefits it on hard data?

What does the research say?

The last – and only – analysis of existing research was published already in 2012. Gathering results of only five small studies conducted till then, it did not come to any conclusion. Three of the studies confirmed the effect of light therapy and two did not. Furthermore, two of those three positive ones were not placebo-controlled. So, these two studies had only proven that the studied groups of depressed mums got better during the treatment – but did not prove that it really was the bright lamps what helped them.

Antidepressant effects of bright light are well established, and there are several rationales for expecting that bright light might also be efficacious for perinatal depression. In pregnant and/or new mothers, bright light treatment could potentially offset insufficient low levels of light exposure; pathological hormonal profiles; co-morbidities, including disturbed sleep and fatigue; and serotonergic dysregulation which has been linked to inadequate maternal behavior. However, the efficacy of light therapy for perinatal depression has been reported in only five published studies, which have produced mixed results.

Crowley, Youngstedt (2012). Efficacy of light therapy for perinatal depression: a review. J Physiol Anthropol.; 31(1): 15.

In 2013, scholars at the Georgian State University focused on mums of low-birth-weight infants placed in a neonatal intensive care unit. The women were naturally worried – and according to the study, bright light therapy helped them sleep better, feel less depressed and generally consider their physical and mental health better, compared to a control group. Nevertheless, the control group did not receive any treatment. Therefore, we don’t know to which extent it might have only been their belief that the bright light would help what made them feel better, rather than true biological effect of the lamps.

Recently, we have also learned about positive results from Michigan, that eight women using Re-Timer Light Therapy Glasses for six months after delivery made over a third of their symptoms disappear within five weeks.

As a reference, the effect sizes observed in this study for depression outcomes (0.78–1.89) are greater than the reported effect size of 0.65 from a meta-analysis of treatments (psychotherapy and medication) for perinatal depression.

Swanson, Burgess, Zollars,Arnedta (2018). An Open-Label Pilot Study of a Home Wearable Light Therapy Device for Postpartum Depression. Arch Womens Ment Health; 21(5): 583–586.

In fact, this comparison is unfair. The results from the mentioned meta-analysis are calculated from controlled trials. The number 0.65 reflects the difference between those who were treated by true medication or psychotherapy and other, control groups which probably improved as well, even without real treatment. The observed effects of 0.78-1.89 in this study, however, put all the improvement together, as if the patients were only helped by lamps and nothing else changed with them. So, unfortunately, it is unlikely that light therapy would work better than medication or psychotherapy.

But regardless of the exact numbers, the study shows that to these eight women the bright light glasses helped. And that it helped them a lot. Even though we still lack the final proof.

The knowledge of 2019 summarized

Currently, we know that almost all the women who tried bright light therapy across all the different trials were helped with their depression. What we don’t know yet, is to what extent it was their own belief and, say, internal healing power what cured them, and which part of the healing was really thanks to the biological effects of the bright light lamps and glasses.

To a scientist, this means we need more research – and we are working on it. Cochrane foundation known for its high-quality reviews of scientific knowledge recently announced a new meta-analytical study of alternative treatments for postpartum depression. Further, a large study is being conducted by in Italy, expected to “to confirm, in a large sample of women, the safety and efficacy of BLT both in prevention and treatment of perinatal depression.” And a double-blind, placebo-controlled study was announced by Dutch scientists.

If BLT reduces depressive symptoms in pregnant women, it will provide a safe, cheap, non-pharmacological and efficacious alternative treatment for psychotherapy and antidepressant medication in treating antepartum depression, without any expected adverse reactions for the unborn child.

Bais, B. et al, (2016). Bright light therapy in pregnant women with major depressive disorder: study protocol for a randomized, double-blind, controlled clinical trial. BMC 16, 381.

Till we receive the final results, the scientist can only hope. But what does that mean to a mum who is depressed right now?

First, you should seek psychotherapy. Traditional, personal one, as long as it is available to you – or an online one in case it might more easily fit into your schedule (and be friendlier to your wallet).

Second, as light therapy helps with most of other depressions, the chances are that it will help you as well. Thus, you can simply trust the light therapy and what those depressed mums did during the study from 2018. Get the same Re-timer glasses and use them daily for 60 minutes immediately after you wake up. Their sleep improved and their depression score dropped from 12 to 7 within five weeks in average – and there is nothing preserving you from the same benefit.

Third, do both! Don’t worry about too many things, you are most likely to be a great parent, because everyone can be, and baby depressions tend to ultimately get away in most of those 10% or 20% of mums and dads affected by them. On the other hand, living in the 21st century with psychotherapy and light therapy being well-known for decades – isn’t it better to use them to your convenience and wellbeing? We know that they both work best together. Both are natural, eco-friendly – and with only positive side effects.