People can suffer from insomnia for a number of reasons, which can be divided into the following categories.

Psychological
Psychological causes of insomnia include crisis, worry and loss, stemming from problems such as bereavement, relationship difficulties and work/exam stress.[1,6] Concerns about being unable to sleep, in particular, can have a self-perpetuating effect on insomnia, which can carry on even when the original cause has been resolved.[6] Insomnia is also commonly associated with other problems such as depression, anxiety and dementia.[6]

Environmental
Disruptions within the sleeping environment or to bedtime routines can cause insomnia.[1] Key culprits include noise, excessive light, heat or cold, an unfamiliar bed, heightened physical or intellectual activity before bedtime (e.g. exercise or reading), or a partner’s snoring or fidgeting.[1,6]

Physical
Insomnia can also stem from an underlying physical condition which causes involuntary movement, pain or discomfort. These include:[1,6]

• Movement disorders e.g. restless leg syndrome
• Respiratory problems e.g. coughing
• Painful conditions e.g. headaches, arthritis and back pain
• Hormonal causes e.g. hot flushes due to the menopause, excess sweating due to hyperthyroidism and nocturia (night time urination) resulting from diabetes
• Other physical illness e.g. pruritus (excessive itching), Parkinson’s disease and gastrointestinal disorders (e.g. ulcers).