Somnology
Pharmacological treatments are used to chemically treat sleep disturbances such as insomnia or excessive daytime sleepiness. The kinds of drugs used to treat sleep disorders include: anticonvulsants, anti-narcoleptics, anti-Parkinsonian drugs, benzodiazepines, non-benzodiazepine hypnotics, and opiates as well as the hormone melatonin and melatonin receptor stimulators. Anticonvulsants, opiates, and anti-Parkinsonian drugs are often used to treat restless legs syndrome. Furthermore, melatonin, benzodiazepines hypnotics, and non-benzodiazepine hypnotics may be used to treat insomnia. Finally, anti-narcoleptics help treat narcolepsy and excessive daytime sleepiness.
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.