Insomnia is defined as unsatisfactory sleep. This may mean the sleep is insufficient or of poor quality due to difficulty falling asleep, being unable to stay asleep or waking early. More women suffer than men, but the incidence increases in both sexes with age. Insomnia can be classed as short-term (less than four weeks) or long-term/persistent (longer than four weeks).  

Common causes of insomnia include: 

• Stress and/or anxiety – related to factors including work, financial worries or health concerns
• Poor sleep hygiene – e.g. using electronic devices, eating or drinking too late in the evening, smoking
• Poor sleep environment – e.g. the room is noisy, too light or the incorrect temperature
• Medical conditions including: bronchitis, asthma, angina, irritable bowel syndrome, acid reflux, headaches, arthritis, incontinence and nocturia (getting up in the night to pass urine), thyroid problems and the menopause. There is a recognised link between insomnia and mental health conditions such as depression, post-traumatic stress disorder and schizophrenia
• Medication and other substances – e.g. prescribed medicines such as antidepressants, epilepsy medication, corticosteroids and NSAIDs, as well as alcohol, caffeine and nicotine
• Jet lag and shift work – both require functioning during dim light, which the body interprets as time to sleep, inducing sleep during the day.