Study of Sleep Inertia in Major Depressive Disorder by the Psychomotor Vigilance Task

This study is investigating "sleep inertia" — the groggy, disoriented feeling upon waking — in people with major depression. Researchers will use a reaction-time test called the Psychomotor Vigilance Task to measure how waking up affects alertness and thinking speed, particularly in people who also have sleep disorders. **You may be eligible if...** - You have been diagnosed with major depressive disorder (MDD) per DSM-5 criteria - You are experiencing sleep problems that require a sleep study (polysomnography) - You either regularly experience difficulty waking up (sleep inertia group) OR you do not experience sleep inertia (comparison group) - You are covered by a health insurance plan - You are able to read and write in French **You may NOT be eligible if...** - You are in the control group and have excessive daytime sleepiness or depression symptoms - You have other psychiatric conditions that would confound the study - You are unable to give consent Talk to your doctor to see if this trial is right for you.