What Causes Insomnia?

Causes of Secondary Insomnia

Secondary insomnia is often a symptom of an emotional, neurological, or other medical disorder, or of another sleep disorder.

The emotional disorders that can cause secondary insomnia include depression, anxiety, and posttraumatic stress disorder. Alzheimer's disease and Parkinson's disease are examples of common neurological disorders that can cause secondary insomnia.

A number of other diseases and conditions can cause secondary insomnia, including:

• Conditions that cause chronic pain, such as arthritis and headache disorders
  
• Conditions that cause difficulty breathing, such as asthma or heart failure
  
• Overactive thyroid
  
• Gastrointestinal disorders, such as heartburn
  
• Stroke
  

Sleep disorders, such as restless legs syndrome, also can cause secondary insomnia. In addition, secondary insomnia can be a side-effect of certain medicines or commonly used substances, including:

• Caffeine or other stimulants
  
• Tobacco or other products with nicotine
  
• Alcohol or other sedatives
  
• Certain asthma medicines (for example, theophylline) and some allergy and cold medicines
  
• Beta blockers (medicines used to treat heart conditions)
  

Causes of Primary Insomnia

Primary insomnia is not due to another medical or emotional condition and typically occurs for periods of at least 1 month. Whether some people are born with a greater chance of having insomnia is not clear yet.

A number of life changes can trigger primary insomnia, including:

• Major or long-lasting stress and emotional upset
  
• Travel or other factors such as work schedules that disrupt your sleep routine
  

Even after these causes go away, the insomnia might stay. Trouble sleeping may persist because of habits formed to deal with the lack of sleep. These habits include taking naps, worrying about sleep, or going to bed early.