What Causes Insomnia?
Insomnia is a very common sleep disorder which affects between 20–50% of people. Insomnia makes it hard to fall asleep or to stay asleep. In some cases insomnia causes you to wake up early and be unable to get back to sleep.
How much sleep we need depends on age, activity levels and other health issues. However regardless of these factors, a restful non-disturbed sleep is vital for all of us. When we don’t sleep, we struggle to function during the day. Our reaction times can be slower, we can struggle with memory, concentration and focus.
All of these factors make it tough for us to carry out daily tasks, and even make us more prone to accidents. Without regular restful sleep we are also at greater risk for a number of physical illnesses and mental illnesses
Understanding sleep regulation
Our sleep is regulated by two processes: our circadian rhythm and sleep-wake homeostasis. Our circadian rhythm is like our internal body clock. It uses the amount of light in our environment along with other factors to determine when we should sleep. A hormone called melatonin is released towards nighttime in reaction to the amount of light we see. This helps us to get ready for sleep. Throughout the night, levels of melatonin fall so that we’re ready to wake up in the morning.
Sleep-wake homeostasis works hand in hand with our circadian rhythm. This system releases a chemical called adenosine throughout the day. Levels of adenosine build up as we go about our day, making us increasingly tired so that we’re ready to go to sleep at night. When we sleep, adenosine reduces to prepare us to wake up. These two systems work hand in hand to regulate our sleep, and it’s when they become disrupted that we experience sleep disorders like insomnia.
Symptoms of insomnia
Symptoms of insomnia include:
- Finding it hard to fall asleep
- Waking up during the night (sometimes multiple times)
- Waking up very early and being unable to get back to sleep
- Feeling tired and unrefreshed when you wake up
- Feeling tired during the day and often struggling to stay awake
- Problems with cognitive functioning: concentration, focus, decision making and memory
- Mental health issues: depression, anxiety, increased stress, low mood.
- Increased risk for accidents and mistakes due to tiredness
Types of insomnia
There are a few types of insomnia we can experience. One individual is likely to experience more than one type of insomnia, for example you could have chronic insomnia and experience it in both the onset and maintenance forms.
- Acute insomnia
Acute insomnia is short term, usually lasting a few days or sometimes weeks. This can be in reaction to a stressful life event or a short illness, and often resolves on its own.
- Chronic insomnia
Chronic insomnia is an ongoing, long term problem. The National Sleep Foundation states that, “Insomnia is usually considered chronic if a person has trouble falling asleep or staying asleep at least three nights per week for three months or longer.”
- Onset insomnia
This refers to problems falling asleep when you first go to bed.
- Maintenance insomnia
This refers to issues staying asleep. Those with maintenance insomnia may wake up multiple times during the night and struggle to get back to sleep.
You may also hear insomnia referred to as primary or secondary. Primary means there are no other medical reasons for the insomnia, and secondary means the insomnia comes alongside other physical or mental health conditions.
Models of insomnia
Models of insomnia simply explain scientific theories about how insomnia is caused and which factors make it an ongoing problem. There are a few models which have been developed by different scientists over the years.
The Stimulus Control Model
The stimulus control model was developed in 1972 by a scientist called Bootzin. The model focuses on the stimulus in our environment which can disturb our sleep, for example behaviours we engage in within the bedroom area which are not sleep related, such as working in the bedroom or watching TV. We then become accustomed to being awake in the bedroom, rather than associating it with sleep, which keeps the cycle of insomnia going.
This article explains that within this model, “Sleep is viewed, in part, a conditioned response to the stimulus of the sleep environment. In insomnia, the bed/ sleep environment instead become stimuli for increased arousal, frustration, and wakefulness.”
The 3P Model
The 3P model of insomnia is also known as the Spielman model of insomnia, because it was developed by Dr Art Spielman in the 1980s. The model explains how insomnia is caused and perpetuated, rather than stemming from one single cause. The three P’s stand for Predisposing factors, Precipitating factors and Perpetuating factors. Let’s take a look at what this means!
- Predisposing factorsThese are factors which make you more likely to struggle with insomnia, but don’t cause it on their own. This can be factors like genetics (if poor sleep runs in your family); personality (if you’re more prone to stress and worrying); and any mental or physical health issues which are present before you experience insomnia.
- Precipitating factorsYou can think of precipitating factors as ‘triggers’: things that happen in your life which cause you to start struggling with insomnia. This could be a new health issue, a stress or trauma in your life, a big change (such as moving house and changing environment), or a change in working hours for example.
- Perpetuating factorsThese are factors which perpetuate the problem, meaning they keep you struggling with insomnia or make the problem worse. This could include poor sleep hygiene habits which you have acquired over the months you’ve struggled with sleep, or maladaptive (meaning unhelpful) coping strategies such as drinking lots of caffeine or napping during the day.
A number of cognitive theories and models have been developed over the years, which have notably been developed by two scientists called Morin and Harvey. Other scientists also developed their own cognitive models and added to research over the years.
This study from the journal of Sleep Medicine Research explains that this model suggests that, “any event or disease process that gives rise to intrusive thoughts, rumination, or perseveration (regardless of the content of the thoughts themselves) should prohibit the initiation and/or maintenance of sleep.”
The Neurocognitive Model
This model expands on the 3P model. This study explains that the model suggests, “insomnia leads to conditioned cortical arousal, manifested as increased high-frequency (beta and gamma) EEG activity during sleep.” Under this theory, during sleep those with insomnia experience higher brainwaves than normal, meaning they aren’t experiencing the restful deep wave sleep we need. This means they are more likely to pick up on external stimuli such as noises, which can startle them out of sleep.
The Psychobiological Inhibition Model
This study explains that this model focuses on the concept that stress leads to, “selective attention toward stressors, and inhibition of the “de-arousal” that normally accompanies sleep.” This means that we become so focused on the factors which are causing stress that we are on high alert, and this prevents the inhibition of arousal which usually helps us sleep. Essentially, the processes which usually help us relax aren’t working properly because we’re so focused on stress in our lives.
The Drosophila Model
This model focuses on predisposition to insomnia, suggesting that factors which are genetic are the primary cause of insomnia. Essentially those of us who have relatives who are more prone to stress, sleep disturbances, anxiety and so on, develop insomnia. This article explains that these inheritable factors include, “the strength and plasticity of the sleep system, the trigger threshold for and intensity of the flight-or-fight response, or the strength and plasticity of sleep homeostasis and circadian processes.”
Factors which can contribute to insomnia
Now we’ve covered the scientific models which theorize how insomnia is caused, we can look at the individual factors which can cause and contribute to insomnia. These are factors which may fit into one or more of the sleep models we’ve discussed, and which are proven to play a significant part in sleep problems.
When we experience stress in our lives, particularly when it’s over a long period of time, it can lead to insomnia. When you’re stressed, your body and mind is on high alert: it’s looking for danger and is ready to take action. This is known as the ‘fight or flight’ state. It means that all of your body’s resources are sent to areas which are going to be needed for action.
This article from Harvard Medical School explains that, “the heart beats faster than normal, pushing blood to the muscles, heart, and other vital organs. Pulse rate and blood pressure go up.” The article then goes on to explain that breathing rate also rises, and more oxygen is sent to the brain to increase alertness and sharpen our senses.
In the short term this stress reaction is helpful as it helps us to protect ourselves. However your body is not designed to withstand this state for long periods of time, so when stress is prolonged it can take its toll. This state of high alert is often known as hyperarousal. This article explains that, “Experts have increasingly come to identify the specific elements of the stress response that contribute to what is known as a state of hyperarousal in which the brain and body operate as if “on alert.””
It’s easy to see that when your body and mind is ready for action, it can be difficult to relax and go to sleep. When you’re in a state which is on the lookout for threats, this can make you more likely to react to external stimuli, reducing the quality of your sleep. The sharpened senses and high alert state we mentioned make you more inclined to wake up in response to a low level noise or slight movements which you would normally sleep through.
Unfortunately once you’ve experienced a few night’s of restless sleep and are already stressed, insomnia only adds fuel to the fire. You may become irritable, more stressed and even worried about not being able to sleep (which increases anxiety). This 2019 study from the Journal of Sleep Research concluded that, “The reciprocal relations indicate a vicious cycle of stress and insomnia that potentially could lead to emotional exhaustion or burnout.”
Stress can come from big changes in your life, such as moving house or starting a new job; losing a loved one; trauma; and any other event which you find tough to cope with. As worrisome as this cycle sounds, both stress and insomnia can be tackled.
Our sleep moves in cycles between lighter and deeper stages of sleep which repeat throughout the night. Each stage is vital for a restful, restorative sleep (as well as for many other functions such as memory processing). We’re less likely to be woken up from slowwave, deep sleep, and more likely to be woken up from lighter stages of sleep.
Aside from these biological changes which occur with age, other factors such as increased prevalence of physical and mental illness in the older population can contribute to insomnia. Often medications taken to deal with these conditions can play a significant part in sleep disorders. This article explains that, “44% of older persons experience one or more of the nighttime symptoms of insomnia at least a few nights per week or more.”
Those who work in shifts are likely to find that their circadian rhythm is disrupted. They may work long hours which change regularly, so the time when they’re sleeping regularly varies (a consistent bedtime is important for restful sleep). Shift workers may work very early in the morning when their circadian rhythm says they should be asleep. Some people may do night shifts, meaning they’re awake throughout the night: when they try to sleep during the day it’s light, making it difficult to fall asleep.
When we travel fairly quickly (such as via airplane) into a country with a different time zone, it can confuse our circadian rhythm. It might be light outside when you’re used to being asleep. Alternatively it may be night time, when if you were at home you would be wide awake. This is what’s known as jet lag. Thankfully this is usually a temporary problem.
Poor sleep hygiene
Sleep hygiene refers to positive habits we use to help us sleep. When we have poor sleep hygiene, it can lead to issues trying to sleep. Poor sleep hygiene includes behaviours and factors such as:
- Having an inconsistent ‘bedtime and ‘wake time’
- Taking lots of naps during the day
- An uncomfortable sleeping environment
- Stimulating activities late at night such as watching TV or playing on your phone
- Eating late at night
- Consuming stimulants late at night (caffeine, alcohol and nicotine)
There are many factors within the bedroom environment which may contribute to insomnia. If the bedroom is too hot or cold, this can disrupt your sleep. If there are loud noises or lots of light from inside or outside your home, it can be disturbing. If you have a partner who snores or struggles with a sleep disorder, it can be difficult to get a restful sleep.
An uncomfortable bed, mattress or pillows can lead to discomfort and lack of support, which in turn can cause problems with sleep. If you use your bedroom for things other than sleep, such as working or watching TV, this can cause your brain to associate the bedroom with a state of wakefulness, rather than sleep.
Mental illnesses of any kind can make it difficult to fall asleep at night: this can include anxiety, depression, mood disorders such as bipolar disorder, and more. It’s difficult to relax when you’re stuck in a tense state or have a lot on your mind. At night there are no distractions and when everything else is quiet, it can sometimes cause your thoughts to feel louder and overwhelm you.
Unfortunately insomnia can also contribute to mental health issues, creating a cycle. However, whether the insomnia or the mental illness came first, this cycle can be broken, and both disorders can be treated!
Physical health issues
Physical health conditions can cause and significantly worsen insomnia. This can be because individual symptoms of the conditions interrupt sleep, such as needing to get up throughout the night to go the toilet; having disorders which cause uncontrollable movements; or experiencing shooting pains (among many other potential symptoms).
Symptoms (like pain) can also make it difficult to get comfortable at night.
Some physical health conditions which commonly lead to insomnia include:
- Breathing issues like asthma
- Chronic pain conditions such as arthritis, fibromyalgia and many more
- Gastrointestinal problems, like acid reflux and Irritable Bowel Syndrome (IBS)
- Endocrine problems
- Neurological conditions like Alzheimer disease and Parkinson’s disease
- Traumatic brain injury (TBI)
- Common virus and infections which can interrupt sleep in the short term
Medications taken for mental illness have been known to disrupt sleeping patterns. In some cases, they may make you tired during the day, leading you to take naps which then disrupts your circadian rhythm. Other mental health medications can make it difficult to relax at night.
Over the counter medications can include ingredients which make it difficult to sleep. For example, some painkillers include caffeine. This article from the American Academy of Sleep Medicine explains that, “Common cold and allergy medicines contain pseudoephedrine and can make it difficult to fall asleep.”
Illegal drugs can lead to insomnia, as well as causing other physical and mental health issues. This 2020 article explains that, “Disturbances in sleep have been found to be prevalent in people who use illicit drugs.”
Other legal substances can be stimulants which can interfere with sleep, such as nicotine, alcohol and caffeine. It’s important to limit these, particularly as you get closer to your ‘bedtime’.
Other sleep disorders
Some other sleep disorders make it tough to get to sleep and to stay asleep throughout the night. Sleep apnea causes your airway to become partially blocked during the night, leading to breathing difficulties which can wake you up. This can happen multiple times throughout the night, meaning you would wake up multiple times and be unable to get a solid block of restful sleep.
Many factors of an individual’s menstrual cycle can contribute to insomnia. Just before and during your period, you may experience a range of uncomfortable symptoms. Period cramps, bloating, heavy bleeding, headaches, back pain and a general sense of discomfort can lead to problems getting comfortable enough to sleep. If you experience bad period pains, it may even wake you up during the night.
The hormones released during your menstrual cycle (including serotonin, progesterone, and estrogen) rise and then fall just before your period starts. These changes can have significant effects on fatigue, mood and other factors. This article on the topic states these hormonal changes, “can be accompanied by night sweats, hot flashes, and vivid dreams or nightmares.”
These changes can even affect our sleep cycles, particularly just before our period starts. This report from the Sleep Health Foundation explains that, “We know that the amount of REM sleep – which is when we have most of our dreams – is less in this part of the menstrual cycle.”
Temperature, both internal and external, can affect how you sleep. In general, lower core temperatures (within the correct range of course) lead to better sleep. Your core temperature rises just after ovulation, which can make it more difficult to sleep.
Hormonal changes combined with practical considerations which come along with pregnancy can lead to a restless night’s sleep. When you’re pregnant, you’re likely to struggle with a frequent need to urinate, even during the night. Leg cramps are common, along with an increase in the chance of restless leg syndrome. You may also struggle with constipation or diarrhea and heartburn!
In more recent years studies have shown that an imbalance of a neurotransmitter in the brain may be causing insomnia. Neurotransmitters are chemical messengers, each type with different vital roles in regulating what happens in our mind and body. The neurotransmitter gamma-aminobutyric acid (GABA) has shown to be lacking in those with chronic insomnia.
GABA is responsible for decreasing or stopping certain nerve impulses. Dr. John Winkelman explains that this, “may lead to an inability to shut down waking signals in the brain”. In essence this means that our brain is still on full throttle, staying alert even when it’s time to sleep.
As a woman ages and enters menopause, they stop having periods and levels of menstrual hormones decline. This is a big change and can lead to insomnia. This 2019 article states that, “approximately 61 percent of women who are postmenopausal experience frequent bouts of insomnia.”
This can be due to changes in hormone levels, hot flashes and night sweats which make it difficult to get comfortable, and medications which are often taken to ease menopause symptoms.
Our genetics play a part in whether we’re likely to struggle with sleep disorders like insomnia. This means that if someone you are related to struggles with insomnia, you are more likely to! As more research is being done, scientists are beginning to identify specific genes which are involved in insomnia, and which connect with insomnia with comorbid disorders.
The more this type of research is developed, the greater the chances of even more successful treatments! This study on the genetics of insomnia concluded that, “Given the prevalence of insomnia and its associated public health impact, advances in our understanding of the genetic underpinnings of the disorder could lead to prevention and treatment efforts that would benefit a substantial proportion of the population.”
Whatever the cause, insomnia can be treated! There are scientifically proven treatments which you can use to help you get a better sleep. You can access medications through your doctor, along with psychological treatments. You can also access psychological treatments privately or through a sleep treatment app like Somnus, which enables you to access treatments when you need them. Let’s take a look at some of your options.
There are a range of medications which can be prescribed for insomnia. There are also some medications and supplements you can get over the counter to aid sleep. It’s important to remember that taking any new medication is a big decision, and should be done from an informed standpoint. Ensure you do your research and find out about potential side effects.
Cognitive behavioural therapy for insomnia (CBT-I)
CBT-I is a form of cognitive behavioural therapy specially adapted to focus on helping you change negative beliefs and behaviour patterns around sleep, instead replacing them with positive, adaptive coping strategies which allow you to get a restful sleep.
CBT-I typically utilizes a number of techniques to help patients including:
- Sleep education: This teaches you about sleep and the science behind it, so you can better understand how and why changing your behaviour can be so helpful.
- Cognitive techniques: This helps to address worries you may have around sleep and bedtime, and alleviate anxiety.
- Stimulus control: This focuses on changing behaviours which may be interfering with your sleep, as well as changing external stimuli which could be making it more difficult for you to sleep.
- Sleep restriction: This technique helps you limit the amount of time you’re in bed and restricts naps, to help you get a more restful sleep throughout the night.
- Relaxation techniques: Often CBT-I combines mindfulness techniques (discussed below) to promote relaxation.
- Paradoxical intention: Depending on the cause of insomnia, some CBT-I will involve periods of lying in bed without falling asleep, to ease the anxiety that often builds up around the bedroom and lack of sleep.
Mindfulness is all about being in the present moment, rather than worrying about the past or future. The practice involves learning to bring your focus back to the here and now when your mind wanders, leading to a deep state of relaxation and calm.
Mindfulness techniques which may be used during treatment can include:
- Guided meditation: You will begin by sitting or lying down in a comfortable position, with your eyes relaxed or closed. The voice of your therapist (or audio recording if you use online resources), will guide you through achieving a deep, relaxed, meditative state.
- Guided visualization: This refers to being guided through picturing specific scenes or events to help you relax, and often to enable you to picture yourself changing your behaviours to result in more restful sleep. This is typically done as part of guided meditation.
- Deep breathing: Deep breathing techniques focus on controlling your breathing and centering yourself, allowing you to be much calmer and focused.
- Progressive muscle relaxation (PMR): You will be guided through tensing and relaxing each individual group of muscles in your body. This brings complete body relaxation, relieving tension and stress.
Mindfulness sessions can be carried out during the day to relieve stress; before bedtime to wind down for sleep; or even in bed to help you drift off to sleep. As you learn the techniques of mindfulness, you can start to use them going forward in your everyday life to keep stress levels low and emotions under control.
Sleep hygiene refers to healthy habits and environmental changes which you can implement to help improve your quality of sleep. Healthy sleep hygiene habits include:
- Having a consistent sleep scheduleGoing to bed and getting up at roughly the same time each day can help to reset your body clock. Consistency is key and will help you to sleep more peacefully.
- Winding down before bedIt’s important to make time to relax before bed. This could include practicing mindfulness, reading a book, listening to calming music or taking a bath for example. You can dim the lights and reduce noise to promote relaxation. It’s also a great idea to avoid screens like watching the TV or being on your phone, as this can make you feel more awake.You could even listen to sleep sounds, which are sounds specifically designed to help you relax, to calm your body and mind, and to ease you into a deep peaceful sleep.
- Limiting naps during the dayAlthough taking naps during the day is tempting, especially when you haven’t been sleeping and are feeling exhausted, it’s important to try to limit them. Take short quick naps if you need to, and try to eliminate them all together if possible. This will help to regulate your body clock.
- Avoiding stimulants near bedtimeAs we’ve mentioned, stimulants such as alcohol, nicotine and caffeine make you feel more awake, and therefore make it tough to sleep. It’s important to avoid these in the hours before you go to bed to help you sleep more restfully.
- Making your bedroom a comfortable, calming spaceThe environment you sleep in has a significant impact on sleep quality. Ensure your bedroom is comfortable, such as making sure you have a comfortable mattress and pillows. You could add personal touches to make your bedroom more cosy, like extra blankets.Having dim lights within the bedroom and curtains or blinds which block out light can help to regulate your circadian rhythm. Some people choose to use eye masks to block out all light, or black out curtains.Ensure that the temperature within your bedroom is not too hot or cold, as this can disturb your sleep: between 60 and 67 degrees Fahrenheit is optimal for sleep. If your partner snores or has a sleep disorder which disturbs you, you could consider earplugs to help block out the noise so that you are able to get a more restful night’s sleep.
It’s also important that your bedroom is only used for sleep. Try not to work in your bedroom or watch TV for example. You need to create the association between the bedroom area and relaxation.
- Eating wellEating a healthy diet is important for all of us, but what and when we eat can play a part in sleeping problems. Try not to eat rich, heavy or spicy foods at night as this can cause digestion issues. Ensure you don’t eat a big meal within the two to three hours before you go to bed, as this can make you feel bloated and too full to sleep. It’s also important you don’t go to bed hungry, as this can be distracting. A light snack before bed can be useful if you find you’re hungry at night.
- ExercisingNot only does exercising have great benefits for physical and mental health, exercising during the day actually helps us to sleep better at night. However, it’s important not to do intense exercise near to your bedtime, because this can make you feel more awake.
- Getting out in natural lightGetting outside in natural light during the day when you’re exercising, or even just sitting in the garden, can be extremely beneficial to help reset your circadian rhythm.
Whatever the cause of your insomnia, don’t lose hope! There are effective self-management strategies and treatments which can help you sleep and enable you to overcome your insomnia.
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