Causes of Insomnia

Many things can cause insomnia including medical illnesses, psychiatric illnesses, mediations, stress and environmental problems. Many times it is easy to determine the cause of insomnia, other times it is not. Many times an identifiable stress cause insomnia - a new job, a divorce, the death of a loved one or financial concerns.

Sleeplessness can run in the family. There is genetic variability in people’s response to caffeine, stress and light in its effect on sleep.

Genetics can cause insomnia.  Genes can be passed on that affect the sleep patterns. Some people are more likely to developing a circadian rhythm disorder. These are disruptions in the body’s internal clock.

Chronic disease can cause insomnia. Almost any chronic disease can cause sleep problems. Those with poorly controlled chronic diseases are more often afflicted with insomnia. Common medical problems linked to insomnia include:

• Arthritis
• Chronic lung disease
• Cancer
• Any disease that causes pain 
• Heart failure
• Overactive thyroid
• Enlarged prostate (increased nighttime urination)
• Acid reflux
• Stroke
• Acute infections such colds or an asthma exacerbations

Medications are a common cause of sleep disorders. Common medications that may cause sleep problems include:

• Antihistamines (Allergy Medicines) (Benadryl)
• Corticosteroids
• Birth control pills
• Some anti-depressants, particularly bupropion (Wellbutrin)
• Thyroid medications
• Drugs for Parkinson's Disease
• Nicotine or nicotine replacement
• Alcohol
• Decongestants (pseudoephedrine [Sudafed])
• Diuretics
• Beta-blockers
• Alpha-antagonists
• Theophylline
• Albuterol
• Dextroamphetamine
• Decongestants
• Stimulants
• Some over the counter herbal remedies
• Central nervous system stimulants

Lifestyle factors are associated with insomnia. Poor sleep habits such as an irregular sleep schedule, eating a lot before bed, poor sleep environment and participating in stimulating activities before bed may lead to insomnia. The job can cause insomnia. Those who travel or participate in shift work can have disturbances in the body’s circadian rhythm – disrupting sleep.

Obstructive sleep apnea (OSA) is a problem that usually presents with the complaint of waking up many times at night, snoring, and the bed partner complaining that there are interruptions in breathing at night. OSA is beyond the scope of this course and will not be discussed further here.

There is no evidence to link race to insomnia.

Women are more commonly affected by chronic insomnia than men. Women with menstrual problems are more likely to have sleep problems then those without.

Insomnia incidence is increased in older adults.  Many reasons have been proposed for this including medical illnesses are more common and there is more psychological stress. Aging is associated with changes in sleeping habits. Changes in the circadian rhythm often occur as one ages.

Some people are afflicted with circadian rhythm problems – which change with aging. The normal body has a typically pattern where it gets tired at around 10-11 PM and wakes up around 7-8 in the morning. This rhythm correlates with the core body temperature. Core body temperature often dips around the time that one gets tired and rises around the time that one wakes up.

Teenagers often have changes in their circadian rhythm. Their core temperature dips later – often at 1-2 AM and rises later in the morning. Therefore, there is a physiological reason that teenagers want to stay up late and sleep in. As teenagers get into there twenties this often reverts back to normal.

Older adults have the opposite situation. Their temperature drops earlier and rises earlier. Therefore, the older adult often wants to go to bed earlier and rise earlier.

Shift work sleep disorder – This is related to those who work varied or abnormal shifts. This can occur because the patient is worried about waking up for an early shift or a rotating shift. Individuals who work until late in the night often need time to relax after work. This makes it hard to sleep.