Insomnia is an inability to fall or to stay asleep.
Causes of insomnia include anxiety, depression, alcohol and drug abuse, jet lag, and chronic painful medical conditions. These and other causes are set out in greater detail below. Insomnia is very common. As many as one in three adults will suffer insomnia at some time or other in their lives. Anxiety Anxiety is characterised by increased alertness and an unpleasant sensation of fear and apprehension.