Insomnia: The Complete Guide for 2021

Do you regularly wake up way before your alarm clock goes off or struggle to stay asleep throughout the night? Ever have nights where you just can’t sleep – no matter how hard you try?

If so, you may have experienced insomnia – and you’re not alone. Insomnia is the most common sleep disorder in the world.

In this guide, we’re going to explore what insomnia is, the symptoms and causes of the disorder, and the different treatments available.

Table of Contents

What is insomnia?

Insomnia is a sleep disorder associated with difficulty falling asleep, staying asleep, or complete lack of sleep, despite adequate opportunity. The term comes from the Latin “in” (no) and “somnus” (sleep).

Approximately 25% of Americans experience insomnia each year, but 75% recover without developing a long-term disorder. However, it’s thought the prevalence of insomnia is under-diagnosed and under-treated in the general population, with many sufferers turning to self-help strategies such as herbal remedies.

excessive daytime sleepiness

Types of insomnia

There are a few different types of insomnia, which are categorized by the symptoms displayed:

  • Sleep onset insomnia: Trouble falling asleep 
  • Sleep maintenance insomnia: Trouble staying asleep
  • Mixed insomnia: Symptoms of both sleep onset and sleep maintenance insomnia
  • Behavioral insomnia of childhood (BIC): Insomnia in children

Sleep maintenance is the most common form of insomnia, with around 50-70% of sufferers experiencing this symptom, followed by sleep onset at approx 35-60%.

Insomnia can be short-term (acute) or long-term (chronic):

  • Acute insomnia usually lasts less than three months and often happens as a result of short-term stress (such as a new job) or an uncomfortable sleeping environment.
  • Chronic insomnia is diagnosed when individuals have trouble sleeping at least three times a week for three months or more. It can be caused by long-term conditions like depression and chronic pain. Anxiety around the sleep problem or fear of being unable to sleep (chronic psychophysiological insomnia) can prolong the disorder for many with chronic insomnia.

Insomnia can also be classified as primary and secondary:

  • Primary insomnia exists on its own and not as a result of an underlying condition
  • Secondary insomnia (comorbid insomnia) happens as a result of an underlying health condition

Because of the difficulty in determining whether a condition is causing insomnia in patients and the fact that insomnia is a risk factor for many of the conditions it coexists with, ‘comorbid insomnia’ has been advised as the preferred term for secondary insomnia.

excessive daytime sleepiness

Symptoms of insomnia

As well as difficulty sleeping, individuals with insomnia often experience a variety of other symptoms due to lack of sleep. 

To reach a diagnosis of general insomnia disorder, patients will usually need to display at least one of the below daytime symptoms alongside sleeping difficulties. 

  • Fatigue or malaise
  • Daytime sleepiness
  • Mood disturbances, e.g. irritability, depression, or anxiety
  • Decreased ability to function at work, school, or socially
  • Lack of energy, motivation, or initiative
  • Difficulty concentrating 
  • Anxiety related to sleeping
  • Gastrointestinal symptoms
  • Tension headaches
  • Accidents while driving or at work
  • Feeling unrefreshed after sleep

Insomnia and lack of sleep come with certain risks and side effects. Along with obvious ones like impaired functioning, it can also contribute to the development of chronic conditions such as depression, diabetes, obesity, and cardiovascular disease.

Causes of insomnia

The causes of insomnia largely depend on the type of insomnia you’re experiencing (i.e. primary, comorbid, acute, or chronic). 

Let’s take a look at some of the common causes below:

Environmental factors

Environmental factors such as noise, bedroom temperature, or an uncomfortable bed can contribute to acute insomnia, preventing individuals from falling asleep or maintaining sleep.

Lifestyle factors

Certain lifestyle factors such as the absence of a bedtime routine, lack of exercise, taking naps during the day, or irregular sleep due to a bed partner or child can contribute to insomnia. You may also experience insomnia if your job requires shift work (and therefore irregular sleeping times), or you frequently travel through multiple time zones.

Too much screen time

Blue light from devices like smartphones, tablets, and computer screens has been found to suppress the secretion of melatonin (a hormone that regulates our sleep-wake cycle and promotes sleep), making it harder to unwind at night and stopping us from getting enough quality sleep.

Underlying sleep disorder

The presence of an underlying sleep disorder can cause chronic and comorbid insomnia. Disorders such as restless leg syndrome, sleep apnea, GERD, parasomnias, and circadian rhythm disorders can lead individuals to experience insomnia. 


Certain medications have been linked to insomnia. These include beta-blockers, statins, corticosteroids, antidepressants, ADHD medications, thyroid medications, and anti-smoking medications. Some over-the-counter drugs can also increase the risk of insomnia, such as antihistamines, pain relief, and herbal medications.

Mental health disorders

Mental health conditions such as stress, anxiety, bipolar and depression can contribute to insomnia. Stressful life events may lead to individuals struggling to fall or stay asleep, and 75% of individuals with depression suffer from insomnia.

Medical disorders

Certain medical disorders can both exacerbate and be exacerbated by insomnia; these include conditions such as stroke, asthma, chronic pain, hyperthyroidism, gastroesophageal reflux, and cardiovascular conditions.


Alcohol has been linked to insomnia in various studies. While alcohol is a depressant and many find it helps initial sleep onset, the quality of sleep is not great. According to Charlene Gamaldo, MD, alcohol is rapidly metabolized in the body, and when it washes the alcohol out, we experience a rebound alertness – usually in the second half of the night.


Caffeine is a stimulant that’s often used to help us stay alert, and as such, has been found to cause sleep disturbances when consumed as much as six hours before bedtime.


Women are more prone to insomnia than men. Hormonal changes such as those experienced during menopause or pregnancy can lead to different types of insomnia. 


Along with hormonal changes in women of a certain age, insomnia has been found to be more prevalent in the older population.

Children with behavioral insomnia (BIC) may experience the disorder due to:

  • Negative associations with sleep or an inability to sleep independently
  • Refusal to go to sleep – using tactics to delay bedtime


If there’s a history of insomnia in your family, you may be at an increased risk of developing the disorder.

Insomnia treatment

The goal with insomnia treatment is to improve sleep quality and quantity and minimize insomnia-related daytime symptoms.

Along with identifying and treating the underlying cause of insomnia, the treatments for the disorder generally fall into two categories:

  • Cognitive behavioral therapy (CBT)
  • Medication

Cognitive behavioral therapy

Psychological and behavioral therapies such as cognitive behavioral therapy for insomnia (CBT-I) have been found to effectively treat chronic primary and comorbid insomnia. CBT-I can include sleep education, stimulus control techniques, sleep restriction techniques, cognitive therapy techniques, and relaxation training.

  • Stimulus control:  Strengthening the association between environment and sleep, e.g. only using the bedroom for sleep, only going to bed when sleepy, and getting up and leaving the room if you can’t sleep
  • Good sleep hygiene: Encouraging behaviors that promote sleep (e.g. daytime exercise and a relaxing bedroom environment) and minimizing behaviors that inhibit sleep (e.g. caffeine before bed and napping during the day). For chronic insomnia, sleep hygiene should be used in combination with other therapies
  • Sleep restriction techniques: Reducing the amount of time spent in bed and keeping a consistent wake time to strengthen circadian rhythms
  • Relaxation training: Practicing relaxation techniques to reduce muscle tension and anxiety and promote sleep 
  • Cognitive therapy techniques: Identifying, challenging, and replacing dysfunctional beliefs and attitudes towards sleep and lack thereof


A range of medications may be prescribed to patients with insomnia depending on the type of insomnia and whether it’s primary or comorbid. Doctors will rarely prescribe sleeping pills these days due to their side effects and how dependent patients can become on them.

  • Hypnotics: Used to treat chronic and acute primary and comorbid insomnia
  • Melatonin-agnostic drugs: Ramelteon has been proven to increase sleep latency and duration, but not wakefulness after sleep onset
  • Antidepressants: Often used in conjunction with treating comorbid depression/anxiety
  • Over-the-counter drugs: Antihistamines, melatonin, and certain herbal treatments are often used as hypnotics, but there’s minimal clinical evidence to support their effectiveness, and they shouldn’t be used to treat chronic insomnia

Getting a diagnosis

If you’re suffering with insomnia symptoms, it’s important to speak to your healthcare provider and get the correct treatment – especially if it’s started to affect your daily life.

Clinicians often follow the ‘three-P’ model:

  1. Predisposing factors: Things that increase your risk of developing insomnia, e.g. family history or a tendency for stress-related poor sleep
  2. Precipitating factors: Medical, environmental, or psychosocial stressors
  3. Perpetuating factors: Things that lead to a vicious cycle of sleep disturbance, e.g. worrying about not getting enough sleep 

To reach an insomnia diagnosis, your clinician may:

  • Ask about sleep characteristics, e.g. bedtime, wake time, sleep latency, sleep duration
  • Ask about lifestyle factors and daytime behaviors, e.g. napping, caffeine and alcohol consumption, and stress factors
  • Evaluate your medical history
  • Carry out a physical examination
  • Ask you to keep a sleep diary to help with your diagnosis
  • Refer you to a sleep clinic 
  • Request a polysomnography (sleep study) to identify symptoms of other sleep disorders
  • Ask you to wear a wrist actigraphy to measure and store movement data, circadian rhythm patterns, and sleep disturbances 

As we’ve learned throughout this insomnia guide, lack of sleep can massively affect our ability to function in day-to-day life. 

If you, or someone you know is having difficulty sleeping, be sure to get in touch with your GP.

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