Sadly, the link between depression and sleep is nothing new. In fact, sleep disturbances are considered to be one of the key indicators when it comes to diagnosing depression.
Finding yourself wide awake in the dead of the night when it feels like the rest of the world is fast asleep can be a lonely experience. But the sad reality is that issues with sleep are a lot more common than you might think. Around a third of people in the UK are believed to be suffering from insomnia; difficulties with sleep that impact their ability to function properly in everyday life.
When it comes to depression alone, it’s thought that around 80% of people with depression have abnormal sleeping patterns. In fact, the link between depression and sleep is so strong that some experts have proposed classifying it with it’s own name - depression-insomnia complex.
As anyone who’s had trouble nodding off knows all too well, problems with sleep can lead to a nightmare cycle of chronic tiredness and low moods. And it’s often difficult to know which one came first.
If you’re depressed and having difficulty sleeping, first and foremost please remember that you are not alone. This unpleasant cycle can and will come to an end with the right support. With depression and sleep so interlinked, the good new is that treating one very often leads to a relief in the other.
But first, let’s get a better understanding of how and why depression and sleep feed into each other so much.
Depression can cause both insomnia (inability to sleep) and hypersomnia (sleeping too much). Different types of depression impact sleep in different ways:
Major depressive disorder - insomnia and excessive tiredness during the day.
Dysthymia - sleeping too much (but waking up without feeling refreshed) or broken sleep (waking up multiple times throughout the night).
Bipolar disorder - contrasting swings between sleeping too much (when “low”) and the inability to sleep at all (when “manic”).
Even if you haven’t been diagnosed with a specific form of depression, if you’ve been having long-standing issues with your sleep it might be worth exploring further. Depression can manifest in lots of different ways - interference in sleep being one of them.
Many of us have a perception of depression as major depressive disorder, but some depressed people can be very high-functioning e.g. dysthymia. And because they’re able to continue going about their daily lives relatively normally - aside from internal feelings of low mood and fatigue - they might not think to consider that depression could be the main culprit.
Depression tends to affect sleep and energy levels in any of the following ways:
When we hear the word insomnia, most of us will think of it as the struggle to fall asleep. But insomnia can also manifest in other ways too. You might, for example, be falling asleep OK but finding it difficult to stay asleep - maybe waking up at various points throughout the night, or rising too early and not being able to nod off again.
For this reason, it’s best to think of insomnia as the inability to get the right quality of sleep (rather than quantity).
Insomnia can be broken up into the following:
Onset insomnia - problems falling asleep
Middle insomnia - waking up repeatedly throughout the night
Terminal insomnia - waking up very early and not being able to fall asleep again.
Insomnia can strike in three different ways:
Transient - experiencing difficulties with your sleep for a period less than 3 weeks. Most of us will experience this form of insomnia at some point in our lives, and it’s often tied to stressful events or life changes.
Cyclical - insomnia that arises as a result of physiological changes in the body e.g. hormones, alcohol addiction. This type of insomnia can be temporary but it can also crop up intermittently; in a cyclical way.
Chronic - insomnia is considered to be chronic when you experience difficulties sleeping at least 3 times a week for a period lasting over a month. Unfortunately, this is the type of insomnia most likely to accompany depression.
Sleep problems caused by depression don’t always manifest as the inability to sleep. In fact, sometimes the reverse can happen. Some people find that depression causes them to over-sleep (AKA hypersomnia). Despite getting what seemed like a full night’s kip they wake up feeling groggy and unrefreshed.
But how does someone wake up feeling tired after so much sleep? Once again, it comes down to the quality of sleep they’re getting.
To understand this better, let’s take a look at the way in which depression tampers with our sleep cycle.
The sleep cycle can be broken into four different stages, followed by REM sleep (rapid eye movement). The first two stages are considered to be light sleep, and the final two are when we enter what’s known as deep sleep.
Deep sleep is the most rejuvenating part of our sleep cycle and is when the body regenerates and produces growth hormones.
When we have a normal, healthy sleep cycle we move through each of these stages whilst we’re sleeping (1 - 4, followed by REM), and then again in reverse order when we wake up.
However, in depressed people this cycle often gets disjointed.
When you’re depressed, REM sleep happens a lot earlier in the night. And that’s not all - depressed people also have a lot more of it. This means that the amount of deep sleep they’re getting is severely diminished. Given that deep sleep is the most nourishing part of our sleep cycle, when it’s pulled out of the equation (as it often is with depression), it’s little wonder that someone would wake up after hours of sleep without feeling the benefits.
The fact that REM occurs more frequently in depression is also interesting. Firstly, REM sleep is when mood-booster serotonin is at its lowest (actually it’s cut off completely). Secondly, REM sleep is the part of our sleep when dreams take place - when our mind is able to put things ‘in order’ and our subconscious works through those troubling emotions and experiences we haven’t quite figured out. In other words, when we’re depressed, reverting to REM might be our way of trying to sort through all the things in our life that have left us feeling hopeless, isolated or unhappy.
Interestingly, certain studies have shown a link between depression and circadian rhythms. The circadian rhythm is our very own internal clock keeping us in sync with the 24hr day, and determining which times throughout the day we feel sleepy or alert.
Got the 3pm post-lunch slump? You can blame your circadian rhythm for that. Because our circadian rhythm determines that we’re most sleepy between 2am - 4am and then again between 1pm - 3pm. Many of us think feeling tired after lunch is all about what we eat, but we’re likely to feel dozy around this time of day regardless.
A recent study seemed to imply a link between the health of our circadian rhythm and the likelihood of developing depression. The study looked at 90 000 adults between 37 and 73 years old. Using an activity tracker, they measured how their activity during the 10 busiest hours of the day compared to the least busy 5 hours.
What they found was interesting. Those with less of a distinction between the two time periods were 6% more likely to develop depression, and 11% more likely to be diagnosed with bipolar disorder.
It certainly points to the vital role circadian rhythms play in our biology, and in supporting both our physical and mental health. Natural light triggers the release of serotonin and the darkness spurs on the release of melatonin. To keep our circadian rhythms in balance, we should be working to embrace natural light and physical activities during the day, and winding down again with the darkness; treating it as our cue for sleep
Modern life has made it easy to manipulate these cycles - whether that means staying up late to binge-watch our favourite shows or spending our days inside and sedentary at our desks. Practising healthy sleeping habits like going to bed and waking up at the same time everyday (yes, on the weekends too!) can help us optimise our natural cycles, and therefore support our physical and mental wellbeing.
With depression and sleep so deeply interlinked it often leads to a bit of a chicken and the egg situation. Sometimes it’s difficult to pinpoint where it all started. As Nerina Ramlakhan writes in her book Tired but Wired, “insomnia isn’t created at night”- exploring what’s keeping you up at night can be a powerful first step towards change. A therapist can support you in getting to the root cause, and many people find that simply unpicking and working through past issues and experiences naturally brings their sleep back into balance again. A therapist can also provide you with tools to put healthier habits into place. This might be in the form of a sleep schedule or it might involve targeting some of the unhelpful thoughts that are holding you back from restful sleep.
Find a therapist today.