Medical case narrative
A 60-year-old man, five years of depression, and a sleep study
What happened
A 60-year-old man in Portugal spent at least five years with depressive and cognitive symptoms, cycling through many antidepressant trials without response.
What it looked like
Treatment-resistant depression with cognitive decline — the kind of case that collects medications and loses hope.
What the labs found
It wasn't a blood test this time. A sleep study measured his apnea-hypopnea index at 52 — severe obstructive sleep apnea. His brain was being starved of oxygen and sleep architecture, dozens of times an hour, every night.
What changed
On CPAP treatment, he improved progressively. At one year there had been no recurrence, his antidepressants had been stopped, and his functionality was reported recovered.
The test that told the story
Sleep study (polysomnography — AHI).
Sources: Cureus 2020 case report (doi:10.7759/cureus.12152), via AJMC coverage; a cohort study (PMC4543247) supports the pattern in other patients.