Nyctophobia is the fear of the dark, or night. While very common in young children, it is also found in adolescents and adults. Nyctophobia has many causes, which range from from a horrifying event witnessed at dark to being naturally uncomfortable in times of shortage of light. While many people are "afriad" of the dark, nyctophobics take it a step further: they literally can't do anything out of fear, and can even hyperventilate and shake uncontrollably. Nyctophobics avoid the dark by staying in a place filled with light, not going outside at night, and keeping a nightlight when they sleep. A common treatment of nyctophobia is gradually increasing time spent in the dark, as well as psychotherapy.
NOTE: Nyctophobia is not to be confused with Scotophobia, the unnatural fear or hatred of Scotland and Scottish culture.