Do I Need to Stop My Antidepressants Before a Sleep Study?

Whether you need to stop taking antidepressants or other medications before your sleep study depends on the specific drugs you take and the decisions you make with your healthcare team. Many common antidepressants can alter your sleep patterns—specifically by suppressing REM sleep—which can make the results of a Multiple Sleep Latency Test (MSLT) (a daytime nap test used to diagnose sleep disorders) difficult to interpret. However, you should never stop taking a prescribed medication without explicit instructions from both your sleep specialist and your prescribing doctor. Together, they will determine if a safe tapering plan is possible, or if the test should be postponed, conducted while you remain on the medication, or substituted with a different assessment.

How Antidepressants Affect Sleep Studies

A sleep study for idiopathic hypersomnia often includes an overnight polysomnogram (PSG) (a test that records brain waves, oxygen, heart rate, and breathing) followed the next day by an MSLT ^[1]. The overnight study checks for other causes of sleepiness, while the MSLT measures how quickly you fall asleep (mean sleep latency) and how quickly you enter REM sleep ^[1]. However, an MSLT is not the only way to diagnose idiopathic hypersomnia; your doctor may also use sleep logs, actigraphy (a wrist monitor), or an extended 24-hour sleep test ^[1].

Certain medications, especially antidepressants like SSRIs (Selective Serotonin Reuptake Inhibitors) and SNRIs (Serotonin-Norepinephrine Reuptake Inhibitors), often suppress REM sleep and can change how sleepy or alert you feel ^[2]. If you take these medications during an MSLT, the test might not accurately capture your natural sleep architecture ^[2][3].

Because diagnosing narcolepsy (a condition often tested for alongside idiopathic hypersomnia) relies heavily on counting SOREMPs (Sleep-Onset REM Periods, or entering REM within 15 minutes), suppressing them with antidepressants can change the test outcome. Research shows that patients who stop REM-suppressing antidepressants before testing are more likely to have multiple SOREMPs and fall asleep faster than those who continue taking them ^[4]. Without stopping these medications, a patient with narcolepsy might be misdiagnosed with idiopathic hypersomnia simply because the medication hid their REM sleep ^[4][5]. On the other hand, stopping a REM-suppressing drug too close to the test can cause “REM rebound,” artificially inflating the amount of REM sleep you get and creating equally misleading results ^[4].

The Washout Period

If your care team decides you should pause your medications, they will guide you through a washout period. This is not just waiting for the drug to completely leave your system; it is a carefully timed clinical interval designed to let your sleep patterns return to normal ^[1].

The length of a washout depends on the specific medication, local clinic protocols, and your personal safety. For example, some centers ask patients to stop most antidepressants two weeks before an MSLT, but require six weeks for longer-lasting medications like fluoxetine ^[4]. These are just common examples, not a universal schedule you should follow on your own. A safe tapering process can take much longer than the washout interval itself, so you should discuss this with your doctors well in advance.

The American Academy of Sleep Medicine (AASM) guidelines emphasize that all medication and substance use must be evaluated before an MSLT ^[1]. This includes many substances that can confound results:

Weighing the Risks and Benefits

Never abruptly stop taking an antidepressant. Doing so can cause severe discontinuation symptoms and a return or worsening of the depression, anxiety, or other condition being treated ^[1]. If you experience marked mood deterioration, severe anxiety, or suicidal thoughts during a taper, contact your prescriber immediately—do not try to manage these symptoms alone.

It is completely valid to feel anxious about altering a medication that is keeping you well. Your psychiatric safety is always more important than a sleep test. If a taper is unsafe, your sleep specialist has other options ^[4][7]:

• Perform the MSLT while you take the medication and document its effects on the results.
• Postpone the test until a taper is safer.
• Use a different diagnostic method, such as 24-hour sleep monitoring.

Study Preparation Checklist

• Bring a complete list of all prescriptions, over-the-counter drugs, and supplements.
• Keep your requested sleep schedule and fill out your sleep diary accurately.
• Ask exactly when to stop using caffeine, nicotine, and alcohol.
• Call the sleep center before the test if you take a medication that was not discussed.