Antidepressants and Sleep: Not All Drugs Are Equal

SSRIs and SNRIs disrupt sleep architecture, but other antidepressants can restore it. 

STUDY: Szynkarek A et al, CNS Drugs 2026; 

STUDY TYPE: Review

FUNDING: Independent

Background

Sleep problems are nearly universal (80-90%) in major depressive disorder. Depression itself shortens REM latency and fragments sleep continuity. Some antidepressants help, and some can make sleep worse, as we’ll see in this review of preclinical and clinical evidence.

Antidepressants that can Worsen Sleep

SSRIs and SNRIs consistently suppress REM sleep, increase REM latency, and fragment sleep continuity. This effect is linked to elevated serotonergic and noradrenergic tone, which keep arousal circuits active and delay REM onset. Fluoxetine and paroxetine are the worst offenders. Among SNRIs, venlafaxine and duloxetine suppress REM more than milnacipran. Around 15-20% of patients have sleep problems on SSRIs and SNRIs.

MAOIs produce the strongest REM suppression of all antidepressants, and phenelzine can eliminate REM sleep entirely in some patients.

Antidepressants that Improve Sleep

Mirtazapine and trazodone spare REM sleep and increase slow-wave sleep, improving overall sleep continuity. Their H1 and serotonin 5-HT2A antagonism promotes deep sleep without the arousal-stimulating effects of reuptake inhibition.

Agomelatine is a melatonin receptor agonist and 5-HT2C antagonist used for depression outside the US. It preserves REM sleep and improves circadian alignment. In a 332-patient randomized controlled trial, agomelatine improved subjective sleep quality and daytime alertness better than venlafaxine.

Bupropion occupies a middle ground: it increases REM density and REM latency without eliminating REM sleep, and changes in REM activity after a single dose predicted subsequent antidepressant response.

Tricyclic antidepressants suppress REM like the SNRIs, but their antihistamine and anticholinergic effects provide partial compensation through sedation.

Ketamine increases slow-wave sleep and raises REM latency, with early-night slow-wave activity proposed as a marker of treatment response.

Practice Implications

1. Even minor benefits in sleep quality can add up over years, suggesting an advantage for mirtazapine, trazodone, agomelatine, and possibly bupropion over SSRI and SNRI antidepressants.
2. When a patient is tired on an SSRI or SNRI, don’t assume it’s a residual symptom of depression. It may be a side effect to the med. Following before and after starting the med with a quick measure like The Pittsburgh Sleep Quality Index (PSQI) can clarify the cause.