Sleep disorders have multiple causes. These include physical and mental issues, certain medicines, the sleep environment, lifestyle issues, or certain periods in life. A frequent physical problem is sleep apnoea, consisting of periods of nocturnal breathing arrest. Other common physical causes are restlessness in the legs (restless-legs syndrome), pain syndromes, or cardiovascular disorders. Sleep disturbances can also accompany several mental diseases, such as depression, anxiety, or bipolar disorder.
Other common triggers are noise, shift work, bruxism (teeth grinding), use of drugs or alcohol, sleepwalking, or the special circumstances of pregnancy and menopause. Also, the influence of worry, stress and burdensome events on sleep should not be underestimated.