Counting sheep

Insomnia is usually one of the first thoughts to spring to mind when considering sleep disorders. The condition, which is the inability to, or the disruption of, sleep is frequently linked to an underlying mental disturbance such as anxiety or depression. However, insomnia is only one of many sleep disorders, which are more common and can be more serious than many people think. Essentially, sleep disorders can be grouped into two broad categories, primary and secondary. Primary sleep disorders can be split according to disturbance in the amount, quality or timing of sleep - dysomnias, and...