Panic attacks during sleep: a hyperventilation-probability model.

Panic attacks during sleep are analysed in terms of a hyperventilation theory of panic disorder. The theory assumes that panic attacks during sleep are a manifestation of severe chronic hyperventilation, a dysfunctional state in which renal compensation has led to a relatively steady state of diminished bicarbonate. Reductions in respiration during deep non-REM sleep lead to respiratory acidosis which triggers hyperventilatory hypocapnea and subsequent panic. A probability model designed to predict when during sleep panic attacks are likely to occur is supported by relevant data from studies of sleep and panic attacks. Implications for treatment are discussed.