Insomnia - Causes 

Insomnia can be caused by many different things, including stressful events, psychiatric problems, underlying physical conditions, and drug and substance misuse. It can also be a side effect of certain medications.

Stressful events

Some people experience insomnia in response to a stressful event, and it continues even when the stress has been resolved. This is because they have learnt to associate the sleeping environment with being alert.

Worrying about work, money or health, a loved one becoming ill or dying, and even noise and light are all causes of Stress and are likely to keep you awake at night. 

Psychiatric problems

Underlying mental health problems can affect your sleeping patterns. They include:

• mood disorders, such as depression or bipolar disorder
• anxiety disorders, such as generalised anxiety, panic disorder or post-traumatic stress disorder
• psychotic disorders, such as schizophrenia

Physical condition

Insomnia can be caused by underlying physical conditions, including:

• heart disease 
• respiratory disease, such as chronic obstructive pulmonary disease or asthma
• neurological disease, such as Alzheimer's or Parkinson's disease
• hormone problems, such as an overactive thyroid
• joint or muscle problems, such as arthritis
• problems with the genital or urinary organs, such as urinary incontinence or an enlarged prostate
• sleep disorders, such as restless legs syndrome, narcolepsy or sleep apnoea
• chronic (long-term) pain

Drug and substance misuse

Alcohol and drug misuse, nicotine and drinking too much caffeine (contained in tea, coffee, energy drinks) can also affect your sleeping patterns.

Medication

Some prescribed treatments or medicines that are available over the counter can cause insomnia. These include:

• antidepressants 
• epilepsy medicine
• medication for high blood pressure (hypertension), such as beta-blockers
• hormone replacement therapy 
• non-steroidal anti-inflammatory drugs (NSAIDs)
• stimulant drugs, such as methylphenidate, which is often used to treat attention deficit hyperactivity disorder (ADHD) or modafinil, which is used to treat narcolepsy (a long-term sleep disorder that disrupts normal sleeping patterns)
• some medicines that are used to treat asthma, such as salbutamol, salmeterol and theophylline