Research

Mixed

Continuous positive airway pressure (CPAP) treatment for sleep apnoea/hypopnoea syndrome significantly improves objective daytime sleepiness and mood, but does not produce major improvements in cognitive function.

If you have sleep apnoea, using CPAP nightly will likely make you less sleepy and improve your mood, especially if you use it for more than 4.5 hours a night. However, do not expect CPAP to fix cognitive issues like memory or processing speed; these may not improve with treatment alone.

GoodQualifiesHIGH confidence
This study confirms significant improvements in objective sleepiness and mood with continuous positive airway pressure, but shows no evidence of major improvements in cognitive function.
H M Engleman et al. · Thorax · 1993

Why this rating

Prospective parallel group study with control, though not randomized, with objective measures (MSLT) and clear statistical reporting.

Source

Daytime sleepiness, cognitive performance and mood after continuous positive airway pressure for the sleep apnoea/hypopnoea syndrome.

H M Engleman et al. · Thorax · 1993

DOI 10.1136/thx.48.9.911

cohort · n=37Cited 181×
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DOI resolved against Crossref · corpus check 2026-06-10

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