Insomnia

Samuel Y Huang

What is Sleep?

Sleep is a recurring state of rest that suspends consciousness and voluntary muscle action.

It is regulated by the circadian rhythm and includes 4-5 sleep cycles consisting of NREM and REM sleep stages.

Sleep disorders can be primary or secondary, with primary disorders further divided into dyssomnias and parasomnias.

Symptoms of sleep disorders include difficulty falling asleep, staying asleep, and abnormal behavior during sleep.

Environmental factors can cause sleep loss, leading to excessive daytime sleepiness and cognitive impairment.

Treatment for sleep disorders and sleep loss may involve sleep hygiene, phototherapy, and sedative pharmacotherapy.

 

Physiology

Sleep cycle consists of sleep stages and sleep latency.

A full night's rest comprises 4-5 sleep cycles, each lasting 90-120 minutes.

Each sleep cycle includes 3 stages of non-REM sleep and 1 stage of REM sleep.

The percentage of REM sleep increases gradually as the night progresses.

Circadian rhythm is a 24-hour cycle of biophysical changes that regulate sleep patterns, hormone production, and body temperature.

Sleep is regulated by the decrease in light, which is detected by melanopsin-containing retinal ganglion cells, leading to the stimulation of the retinohypothalamic tract.

This stimulation causes norepinephrine release from the suprachiasmatic nucleus of the hypothalamus, which in turn triggers melatonin release from the pineal gland and induces sleep.

 

Mnemonic for stages of sleep: BATS D: Beta waves, alpha waves (eye closure), theta waves (N1), Sleep spindles (N2), Delta waves (N3)

 

 

Insomnia, a sleep-wake disorder, is prevalent worldwide and affects around 10% of the population.

The prevalence of insomnia is higher among women, shift workers, and individuals with physical or mental disorders or disabilities.

DSM-IV	DSM-5
Name: Primary Insomnia	Name: Insomnia Disorder
Disorder Class: Sleep Disorders	Disorder Class: Sleep-Wake Disorders
A. The predominant complaint is difficulty initiating or maintaining sleep, or nonrestorative sleep, for at least 1 month.	A. A predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms: Difficulty initiating sleep. (In children, this may manifest as difficulty initiating sleep without caregiver intervention.) Difficulty maintaining sleep, characterized by frequent awakenings or problems returning to sleep after awakenings. (In children, this may manifest as difficulty returning to sleep without caregiver intervention.) Early-morning awakening with inability to return to sleep. D. The sleep difficulty is present for at least 3 months.
B. The sleep disturbance (or associated daytime fatigue) causes clinically significant distress or impairment in social, occupational, or other important areas of functioning.	B. The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning.
	C. The sleep difficulty occurs at least 3 nights per week.
	E. The sleep difficulty occurs despite adequate opportunity for sleep.
C. The sleep disturbance does not occur exclusively during the course of narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia.	F. The insomnia is not better explained by and does not occur exclusively during the course of another sleep-wake disorder (e.g., narcolepsy, a breathing-related sleep disorder, a circadian rhythm sleep-wake disorder, a parasomnia).
D. The disturbance does not occur exclusively during the course of another mental disorder (e.g., major depressive disorder, generalized anxiety disorder, a delirium).	H. Coexisting mental disorders and medical conditions do not adequately explain the predominant complaint of insomnia.
E. The disturbance is not due to the direct physiological effects of a substance (e.g., a drug of abuse, a medication) or a general medical condition.	G. The insomnia is not attributable to the physiological effects of a substance (e.g., a drug of abuse, a medication).
	Specify if: With nonsleep disorder mental comorbidity, including substance use disorders With other medical comorbidity With other sleep disorder Coding note: The code 780.52 (G47.00) applies to all three specifiers. Code also the relevant associated mental disorder, medical condition, or other sleep disorder immediately after the code for insomnia disorder in order to indicate the association. Specify if: Episodic: Symptoms last at least 1 month but less than 3 months. Persistent: Symptoms last 3 months or longer. Recurrent: Two (or more) episodes within the space of 1 year. Note: Acute and short-term insomnia (i.e., symptoms lasting less than 3 months but otherwise meeting all criteria with regard to frequency, intensity, distress, and/or impairment) should be coded as another specified insomnia disorder

 

Substance Abuse and Mental Health Services Administration. Impact of the DSM-IV to DSM-5 Changes on the National Survey on Drug Use and Health [Internet]. Rockville (MD): Substance Abuse and Mental Health Services Administration (US); 2016 Jun. Table 3.36, DSM-IV to DSM-5 Insomnia Disorder Comparison. Available from: https://www.ncbi.nlm.nih.gov/books/NBK519704/table/ch3.t36/

Predisposing vs precipitating vs perpetuating factors

Insomnia disorder is a complex condition that may be influenced by a range of factors, including predisposing factors, precipitating events, and perpetuating factors. Predisposing factors, such as a history of childhood trauma, chronic mental health conditions like depression and anxiety, and a history of shift work or erratic sleep patterns, increase the risk of developing insomnia disorder. Precipitating events, such as experiencing a severe accident leading to physical injury or experiencing a significant loss like divorce or death of a loved one, can lead to sleep disruption. Perpetuating factors, which are behavioral and cognitive factors that sustain poor sleep over time, include behaviors like watching television in bed while trying to fall asleep, staying in bed for extended periods of time to obtain more sleep or taking long naps during the day, and anxiety and worry about sleep loss. Understanding the predisposing factors, precipitating events, and perpetuating factors of insomnia disorder can help healthcare professionals develop effective treatment plans for their patients.

 

Considerations for Management:

For all patients, providing education on sleep hygiene and optimizing the management of any comorbid conditions is recommended.

For short-term insomnia, addressing the triggers and starting a brief course of pharmacotherapy may be considered.

For chronic insomnia, the first-line treatment is multicomponent cognitive behavioral therapy for insomnia (CBT-I). If CBT-I is not successful, the diagnosis should be reassessed, and comorbidities and exacerbating factors should be considered. For select patients, pharmacotherapy may be considered.

 Behavioral and cognitive therapies are effective non-pharmacological treatments for insomnia. The goal of these therapies is to improve sleep habits and promote better sleep quality. Sleep hygiene education is an important aspect of therapy and involves avoiding factors that may trigger or exacerbate insomnia, such as alcohol, caffeine, and nicotine. Stimulus control aims to reestablish the association between bed/bedroom and sleep by establishing a consistent sleep/wake schedule, avoiding engaging in other activities in bed, and waiting to go to bed until feeling sleepy. Cognitive therapy focuses on identifying and reframing dysfunctional beliefs about sleep, while counseling and psychoeducation provide support and information to patients. Paradoxical intention is a technique used in cognitive behavior therapy for chronic insomnia aimed at reducing the anxiety and stress surrounding being unable to sleep. Relaxation training techniques such as progressive muscle relaxation, visual imagery, and biofeedback can help reduce physical and cognitive arousal and anxiety. Sleep restriction therapy is another effective technique used to reduce sleep latency, where the patient is advised to restrict time spent in bed to only the time spent sleeping and gradually increase this time. CBT-I combines cognitive therapy, stimulus control, and sleep restriction therapy, possibly with the addition of relaxation training, and is considered the first-line treatment for chronic insomnia.

 

Pharmacotherapy is one of the treatment options for insomnia; however, the evidence supporting its benefits is weak. Commonly used drugs for sleep-onset insomnia include melatonin, ramelteon, Z-drugs (eszopiclone, zaleplon, zolpidem), benzodiazepines (preferably short-acting benzodiazepines like triazolam), and suvorexant (orexin antagonist). For sleep-maintenance insomnia, Z-drugs (eszopiclone, zolpidem), doxepin, and suvorexant are useful, while doxepin and suvorexant are recommended for early-morning awakening. If the patient has comorbid depression, doxepin, mirtazapine, and trazodone may be used. However, benzodiazepines should be used with caution due to their high risk of addiction, and only for short-term use. Short-acting agents are more appropriate for sleep-onset insomnia, while longer-acting agents are more suitable for sleep-maintenance insomnia but increase the risk of next-day effects. The use of benzodiazepine receptor agonists should be avoided as a first-line medication for the treatment of insomnia in older adults and patients with a history of substance use disorder or drug dependence.

 

 

It is important to note that this article is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment, and it is recommended that you seek the advice of a healthcare professional for any questions or concerns you may have regarding your symptoms or starting a new treatment regimen.