from insomnia due to other medical conditio ns. High-altitude periodic breathing has a
pattern that resembles Cheyne-Stokes breathin g but has a shorter cycle time, occurs only
at high altitude, and is not associated with heart failure. 
Central sleep apnea comorbid with opioid us e can be differentiated from other types of
breathing-related sleep disorders based on the use of long-acting opioid medications in
conjunction with polysomnographic evidence of central apneas and periodic or ataxic
breathing. It can be distinguished from inso mnia due to drug or substance use based on
polysomnographic evidence of central sleep apnea.
Comorbidity
Central sleep apnea disorders are frequently pr esent in users of long-acting opioids, such
as methadone. Individuals taking these medi cations have a sleep-related breathing disor-
der that could contribute to sleep disturbances and symptoms  such as sleepiness, confu-
sion, and depression. While the individual is  asleep, breathing patterns such as central
apneas, periodic apneas, and ataxic breathing may be observed. Obstructive sleep apnea
hypopnea may coexist with central sleep apnea,  and features consiste nt with this condi-
tion can also be present (see “Obstructive Sleep Apnea Hypopnea” earlier in this chapter).
Cheyne-Stokes breathing is more commonly obse rved in association with conditions that
include heart failure, stroke, and renal failure and is seen more frequently in individuals
with atrial fibrillation. Individuals with Ch eyne-Stokes breathing are more likely to be
older, to be male, and to have  lower weight than individual s with obstructive sleep apnea
hypopnea.