Although the precise function of sleep is unknown, decades of research strongly implicate that sleep has a vital role in central nervous system (CNS) restoration, memory consolidation, and affect regulation. Slow-wave sleep (SWS) and rapid eye movement (REM) sleep have been of significant interest to psychiatrists; SWS because of its putative role in CNS energy recuperation and cognitive function, and REM sleep because of its suggested involvement in memory, mood regulation, and possible emotional adaptation. With the advent of the polysomnogram, researchers are now beginning to understand some of the consequences of disrupted sleep and sleep deprivation in psychiatric disorders. The same neurochemistry that controls the sleep-wake cycle has also been implicated in the pathophysiology of numerous psychiatric disorders. Thus it is no surprise that several psychiatric disorders have prominent sleep symptoms. This review will summarize normal sleep architecture, and then examine sleep abnormalities and comorbid sleep disorders seen in schizophrenia, as well as anxiety, cognitive, and substance abuse disorders.

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Sleep-disordered breathing (SDB) is a common disorder that has numerous medical consequences including cardiovascular morbidity. The clinical presentation in women is frequently vague, leading to its under-recognition in this population. Sleep is known to influence several female hormonal cycles including estrogen, progesterone, prolactin, luteinizing hormone (LH), and follicle stimulating hormone (FSH); consequently, sleep disruption may have adverse effects on female health including pregnancy. Miscarriage, defined as the loss of a pregnancy in the first trimester, occurs in one in four pregnancies; in up to half of cases, the cause may be unknown. Risk factors for miscarriage include increased age, increased weight, and a history of polycystic ovarian syndrome, all of which are also risk factors for SDB. Since SDB is frequently accompanied by sleep fragmentation and intermittent hypoxemia, we speculate that these factors may contribute to miscarriage risk. If this is the case, then treatment of SDB may be a possible intervention for subsequent pregnancies.