According to the third edition of the International Classification of Sleep Disorders (ICSD-3), insomnia is characterized by difficulty in either initiating sleep, maintaining sleep continuity, or poor sleep quality. These symptoms occur despite the presence of adequate opportunity and circumstance for sleep and result in daytime dysfunction.

Insomnia is prevalent in 10% to 15% of the general population. Insomnia is a chronic problem in 31% to 75% of patients, with more than two-thirds of patients reporting symptoms for at least 1 year.

A detailed sleep history is essential for the evaluation of insomnia. The clinician should be able to identify if the sleep disturbances are from difficulty in initiating sleep or maintaining sleep or both. The cause of insomnia could be other health conditions, genetic, environmental factors, lifestyle factors etc

Lets look at different causes of insomnia

Which other health conditions can cause insomnia?

The majority of patients with insomnia also have comorbidities : only 4.1% of patients with insomnia did not have a comorbidity.

The causes of insomnia are many, the most important of which are medications, drug or alcohol abuse, psychiatric disorders like depression or anxiety, medical disorders (such as arthritis, asthma, Parkinson’s disease, hyperthyroidism, prostate hypertrophy, degenerative neurological disorders, renal disorders, heart failure, rhinitis), poor sleep hygiene, and other disorders like sleep apnea, periodic limb movements, conditioned insomnia (behavioral conditioning), restless legs syndrome, circadian rhythm disorder or advanced/delayed sleep-phase syndrome.

Neurological causes such as fibromyalgia and Morvan’s syndrome, medical causes such as gastroesophageal reflux disease, and in children, sleep-onset association disorder and limit-setting sleep disorder also need to be identified and addressed since these can commonly present as chronic insomnia.

Are genetic factors responsible for insomnia?

Sleep-wake traits, such as sleep duration and timing, are heritable and regulated by numerous genes. Evidence suggests significant heritability and multigene involvement in the pathophysiology of insomnia.

Genes linked to brain functioning, arousal regulation, and sleep-wake processes have been most consistently found to be associated with insomnia. The complex interplay of these genes may account, at least in part, for the heterogeneity observed in insomnia symptoms and consequences.

Which environmental factors cause insomnia?

Any distractions in the environment where you sleep can cause insomnia. Some of the distractions could be noise (snoring noise) , light or extreme temperatures. Extended exposure to environmental toxins and chemicals may prevent you from being able to fall asleep or stay asleep.

Could stress be a contributing factor to insomnia?

Sleep Reactivity and Insomnia: Genetic and Environmental Influences – Sleep reactivity to stress has a substantial genetic component, as well as an environmental component. The finding that FIRST scores and insomnia symptoms share genetic influences is consistent with the hypothesis that sleep reactivity may be a genetic vulnerability for developing insomnia.

Which lifestyle factors contribute to insomnia?

Assessment of the sleep hygiene practices such as activities performed just before bedtime including nighttime consumption of alcohol and caffeinated beverages, use of electronic gadgets at bedtime and frequency of daytime naps etc can also be helpful to determine the cause of sleep disturbances.


Diagnosis and treatment of chronic insomnia – algorithm for treatment is insomnia management.

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