Sleep
Insomnia is a general term for difficulty falling asleep and/or staying asleep. Insomnia is the most common sleep problem, with many adults reporting occasional insomnia, and 10–15% reporting a chronic condition. Insomnia can have many different causes, including psychological stress, a poor sleep environment, an inconsistent sleep schedule, or excessive mental or physical stimulation in the hours before bedtime. Insomnia is often treated through behavioral changes like keeping a regular sleep schedule, avoiding stimulating or stressful activities before bedtime, and cutting down on stimulants such as caffeine. The sleep environment may be improved by installing heavy drapes to shut out all sunlight, and keeping computers, televisions and work materials out of the sleeping area.
Ventrolateral preoptic nucleus
Lesions in the VLPO in rats results in 50-60% decrease in NREM sleep time and prolonged insomnia. It is hypothesised that disruption of the VLPO results in reduced and irregular inhibition of the arousal system by VLPO meaning patients with insomnia wake up several times during the night. More recent research suggests insomnia could be due to an imbalance of input to arousal system and VLPO neurons, including orexin neuron signalling. Orexin-receptor antagonists are currently being developed for the treatment of insomnia.