Sleep Terror Disorder    

Sleep Terror Disorder, although it sounds similar to nightmare disorder, is easily distinguished from the latter. It occurs most frequently during the first third of a sleep episode, and the dream that causes the terror is remembered vaguely or not at all. The terror is "announced" by a scream, and the person is confused and difficult to awaken or comfort. The episode is forgotten by the next day. During the episode, there are obvious signs of arousal, including sweating, rapid heart beat, and fast breathing. 

As with Nightmare Disorder, onset is typically in childhood, but somewhat later (between 4 and 12 years old). In children, the disorder usually stops at adolescence. However, Sleep Terror Disorder may also start in adults between 20 and 30, in which case it is more likely to become chronic. The sleep net site has information on sleep terror disorder, as well as on many other sleep disorders.