Introduction

Sleep disorders are often a symptom of psychiatric disorders. A third of individuals who have significant insomnia or hypersomnia in the general population suffer from a primary psychiatric disorder (Balon and Singareddy 2001). In fact, assessment of sleep problems is part of the diagnostic criteria for numerous psychiatric disorders.

Depressive Hypersomnia

• Depression and hypersomnia are frequently linked with one another.
• It is thought that this may be due to a reduction in hypocretin secretion in depressed individuals (Remember, the hypersomnia narcolepsy is a result of reduced hypocretin-containing cells, so this theory makes sense) (Salin-Pascual 2001).
• Patients suffering from depressive hypersomnia frequently awake early in the morning and feel tired in the early evening, a phenomenon that occurs because, in patients with depressive hypersomnia, the circadian rhythm is phase advanced
• In many depressed individuals, REM sleep periods are closer together, more intense, and longer lasting than in normal individuals (Hobson 1995).
  • Because of this fact, REM sleep deprivation, as well as total sleep deprivation, has an antidepressant effect, although the underlying mechanism of this occurrence in not yet understood (Salin-Pascual 2001).

Post-traumatic Stress Disorder (PTSD)

• Parasomnias have been linked with Post-traumatic Stress Disorder.
• Individuals that have survived extremely stressful situations (war veterans, concentration camp survivors etc.), may relive their experiences in their sleep in a combination of sleepwalking, sleep talking, and night terrors (Hobson 1995).
• These parasomnias generally arise from NREM sleep, so individuals suffering from PTSD sleep problems are treated with benzodiazepine to suppress NREM sleep (Hobson 1995).