How Does Citalopram Affect Your Sleep?

Citalopram, one of the most widely prescribed SSRIs, reshapes your sleep architecture in several distinct ways. The most consistent and well-documented effect is a strong suppression of REM sleep, the stage associated with dreaming. But citalopram’s reach extends beyond REM: it can trigger insomnia or drowsiness (sometimes both at different points in treatment), increase sensitivity to evening light, and occasionally provoke restless legs or teeth grinding at night. The overall picture depends on how long you have been taking the drug, your dose, and even your genetic makeup.

REM Sleep Takes the Biggest Hit

The single most reliable sleep-related effect of citalopram is a reduction in rapid eye movement (REM) sleep. In a study of depressed patients undergoing polysomnography, researchers found a significant decrease in the amount of REM sleep along with a significant lengthening of the time it took to enter the first REM period. These changes appeared within the first weeks of treatment and persisted throughout the course of the study.¹ A separate study comparing citalopram directly against paroxetine, another SSRI, confirmed that both drugs significantly suppressed REM sleep and also increased sleep fragmentation, meaning more brief awakenings during the night.²

REM suppression is not unique to citalopram; virtually all SSRIs do this. The mechanism traces back to serotonin’s role in gating the brain’s transition into REM. When serotonin levels at the synapse rise, as they do with any SSRI, the brainstem circuits that initiate REM sleep get inhibited. For most people this manifests as less time dreaming, though the clinical significance of losing some REM sleep remains debated. Some researchers see it as a nuisance side effect, while others have argued the REM changes may be intertwined with the antidepressant effect itself.

The First Weeks Feel Different From Month Three

If you have just started citalopram and your sleep has gotten worse, you are not imagining things. Research shows that the drug’s acute effects on sleep differ substantially from what happens once your brain has adapted to the medication over weeks. Early on, the sudden flooding of serotonin tends to be more disruptive: sleep onset may take longer, awakenings are more frequent, and the overall quality of sleep can feel worse than baseline. After several weeks of continuous dosing, many of these acute disruptions soften, though REM suppression tends to persist.³

This is worth knowing because many people abandon an SSRI in the first two weeks precisely when the sleep disruption is at its worst. If you are going through that rough patch, it can help to know that the acute phase is typically the most turbulent. The brain’s serotonin receptors gradually adjust to the new level of serotonin activity, and what researchers call “serotonergic transmission” reaches a different equilibrium. That does not guarantee perfect sleep, but the early-treatment insomnia often eases considerably.

Insomnia, Drowsiness, or Both

One of the more confusing aspects of citalopram’s relationship with sleep is that it can cause insomnia in some people and excessive sleepiness in others. Clinical trial data consistently lists both insomnia and somnolence (daytime sleepiness) among the drug’s reported side effects. In a study examining citalopram and doxepin for patients with comorbid insomnia and anxiety, a small number of citalopram-treated patients experienced worsened insomnia as an adverse reaction, while the drug overall showed meaningful improvement in sleep quality for the broader group.⁴

This seeming contradiction makes more sense when you consider that the drug affects multiple serotonin receptor subtypes with opposing effects on wakefulness. Stimulation of some serotonin receptors promotes arousal, while stimulation of others encourages sleep. The net effect on any given person depends on receptor sensitivity, dose, timing of the dose, and how much of the sleep problem was being driven by the underlying mood or anxiety disorder in the first place. When depression or anxiety is the root cause of poor sleep, treating that condition with citalopram often improves sleep on balance, even if the drug introduces its own disruptive effects.

One practical tip that clinicians commonly suggest: if citalopram is making you feel wired at night, taking your dose in the morning rather than the evening can help. If it makes you drowsy, an evening dose may work in your favor. This is not a universal fix, but it is a simple adjustment worth trying before assuming the medication is incompatible with decent sleep.

Citalopram Makes Your Brain More Sensitive to Light at Night

A less widely known effect of citalopram involves your body’s internal clock. In a controlled study, a single dose of citalopram increased melatonin suppression by roughly 47% when participants were exposed to light. All participants showed more suppression of their melatonin under citalopram compared to placebo, and their melatonin onset also shifted later under normal room lighting conditions.⁵

Melatonin is the hormone that signals your body it is time to wind down. When citalopram amplifies the degree to which ordinary room light suppresses melatonin, the practical consequence is that your brain gets a weaker “it’s nighttime” signal than it normally would. This could push your sleep timing later and make it harder to fall asleep at your usual hour, especially if you spend evenings in well-lit rooms or staring at screens. The finding suggests that people on citalopram may benefit more than average from dimming lights in the evening and limiting screen exposure before bed. It also partially explains why some people report a vague sense that their sleep-wake rhythm has shifted after starting the medication.

Restless Legs and Limb Movements During Sleep

Citalopram has been linked to restless legs syndrome and periodic limb movements during sleep, a condition where your legs (and sometimes arms) jerk or twitch repetitively throughout the night. A review of the literature scored the strength of evidence linking various drugs to these movement disorders, and citalopram was among the SSRIs with the strongest evidence for inducing or worsening periodic limb movements.⁶ Case reports have described patients developing severe restless legs symptoms after starting citalopram, with one case involving a woman sent to the emergency department due to the intensity of her symptoms at a higher dose.⁷

These movement-related effects are thought to stem from serotonin’s interaction with dopamine pathways. Dopamine plays a central role in suppressing unwanted movements during sleep, and the serotonergic boost from an SSRI can indirectly dampen dopamine signaling in areas of the brain that regulate motor control. If you have started citalopram and notice a new urge to move your legs at bedtime, or if a bed partner reports that your legs are twitching at night, this is a recognized side effect and worth mentioning to your prescriber. It does not necessarily mean you need to stop the medication, but dose adjustments or adding a low-dose dopamine-related treatment are options that have been used clinically.

Teeth Grinding at Night

Sleep bruxism, the involuntary grinding or clenching of teeth during sleep, is another side effect that has been reported with citalopram and other SSRIs. At least one published case report documented the onset of nighttime teeth grinding roughly two weeks after starting citalopram.⁸ The mechanism is not fully established but likely involves serotonin-mediated changes in jaw muscle activity during sleep. Some clinicians suspect it involves the same serotonin-dopamine interplay that drives restless legs, since dopamine also helps regulate rhythmic movements of the jaw.

Bruxism can go unnoticed for a while because you are asleep when it happens. Common signs include waking up with jaw soreness, headaches concentrated around the temples, or a bed partner hearing grinding sounds. If you develop these symptoms after starting citalopram, a dental night guard can protect your teeth while you and your doctor decide whether to adjust the medication. In some cases, adding buspirone, a serotonin-modulating anti-anxiety drug, has been used to counteract SSRI-induced bruxism, though the evidence base for that approach is still thin.

What Happens to Your Dreams

Because citalopram so effectively suppresses REM sleep, you might expect it to dampen dreaming altogether, and for many people it does exactly that. Research on antidepressants and dreaming has found that the great majority of these drugs reduce how often people recall their dreams. When depression improves with treatment, the emotional content of dreams also tends to shift in a more positive direction.⁹

That said, a subset of people report the opposite experience: unusually vivid or disturbing dreams after starting an SSRI. The same review noted that some increases in nightmare frequency have been reported with drugs that disrupt sleep or during withdrawal from certain psychotropic medications. The paradox may be explained by what is sometimes called REM pressure. When a drug suppresses REM for much of the night, the brain sometimes “catches up” with unusually intense bursts of REM late in the sleep period, and those compressed REM episodes can produce particularly vivid or emotionally charged dreams. This effect is especially prominent when a dose is missed or the drug is being discontinued, which creates an abrupt REM rebound.

What Stopping Citalopram Does to Sleep

Discontinuation of citalopram tends to produce a mirror image of the drug’s effects on REM sleep. Once the serotonergic suppression lifts, the brain rebounds with an increase in REM sleep that can be sudden and intense. People going through SSRI withdrawal often describe a dramatic surge in vivid, emotionally loaded dreams or outright nightmares. The rebound period varies but typically lasts a few weeks as the brain’s serotonin system recalibrates.

Beyond the dream changes, some people experience a temporary return or worsening of insomnia during withdrawal. This is one reason clinicians generally recommend a gradual taper rather than abruptly stopping citalopram. A slow reduction in dose gives the sleep system time to readjust without the dramatic swings that come with an overnight change in serotonin levels.

Your Genes Influence How Much Sleep Is Affected

Not everyone metabolizes citalopram at the same rate. The liver enzyme CYP2C19 is primarily responsible for breaking down citalopram, and genetic variations in this enzyme create a spectrum from ultra-rapid metabolizers (who clear the drug quickly) to poor metabolizers (who clear it slowly and therefore have higher blood levels at any given dose). A large-scale analysis found that slower CYP2C19 metabolizers taking citalopram or escitalopram reported significantly more side effects overall, and specifically, slower metabolizers were more likely to report sleep problems. Among escitalopram users, for instance, about 18.5% of poor metabolizers reported sleep problems compared to about 14.4% of ultra-rapid metabolizers.¹⁰

This matters practically because pharmacogenomic testing is increasingly available. If you have struggled with sleep side effects on citalopram and discover you are a poor or intermediate metabolizer, a lower dose might achieve the same antidepressant effect with fewer sleep disruptions. Some prescribers now order these tests before starting SSRI therapy, though the practice is far from universal.

How Citalopram Compares to Other Options for Sleep

If sleep quality is a primary concern, citalopram is not the most sleep-friendly antidepressant available. A head-to-head trial comparing citalopram to mirtazapine found that while both drugs improved sleep disturbances, mirtazapine produced faster improvements in sleep quality and better alertness the following morning.¹¹ Mirtazapine works through a different mechanism that includes antihistamine effects, which naturally promote sedation and sleep consolidation. It is often chosen specifically when insomnia is a dominant symptom alongside depression.

Among the SSRIs themselves, citalopram’s sleep profile is fairly typical. Paroxetine, sertraline, and fluoxetine all suppress REM sleep and can cause insomnia or drowsiness. Trazodone, while technically an antidepressant, is used at low doses almost exclusively as a sleep aid because of its strong sedating properties. These distinctions matter when you and your prescriber are weighing the tradeoffs between mood benefits and sleep side effects. If citalopram is working well for your depression or anxiety but your sleep is suffering, adding a low-dose sleep-promoting agent is often more practical than switching to a different SSRI that would likely have similar sleep effects.

Sleep Effects in Older Adults

Citalopram has been widely studied in older adults, partly because its relatively clean drug-interaction profile makes it attractive for people already taking multiple medications. A long-term open study in elderly patients with emotional disturbances found that the majority of patients reported no side effects at all. Among those who did, drowsiness and sleep disturbances were each reported by only about 3% of the group, while tiredness was somewhat more common at around 12%.¹²

The relatively low rate of sleep-related complaints in this population may partly reflect the fact that many older adults have significant baseline sleep problems related to depression and anxiety, and treating those conditions offsets the drug’s inherent sleep-disrupting tendencies. However, older adults are also more vulnerable to the circadian effects described earlier, as melatonin production naturally declines with age. A drug that further suppresses melatonin signaling could have a proportionally larger impact on an aging circadian system, even if this does not always show up as a complaint in clinical studies.

Citalopram and Menopausal Sleep Problems

Sleep disruption during menopause is extremely common, driven by hormonal changes, vasomotor symptoms like hot flashes, and shifts in mood. A randomized trial compared citalopram and venlafaxine against placebo for sleep disturbances in menopausal women and found that both active drugs significantly improved sleep quality scores compared to placebo. Citalopram’s improvement was slightly better numerically than venlafaxine’s, though the difference between the two drugs was not statistically significant.¹³

This study highlights an important point: whether citalopram helps or hurts your sleep depends heavily on what is driving the sleep problem. When the underlying issue is anxiety, depression, or hormonal flux causing mood instability and hot flashes, citalopram can improve sleep overall even though the drug itself has sleep-disrupting properties in isolation. The net effect is what matters. A person whose insomnia stems primarily from racing anxious thoughts at night is a very different clinical situation from a person with good mental health who was prescribed citalopram for something like chronic pain off-label.

How Serotonin Pulls Sleep in Multiple Directions

The reason citalopram’s effects on sleep are so varied is that serotonin does not have a single, clean role in the sleep-wake cycle. Research using serotonin receptor antagonists alongside citalopram has shown that different receptor subtypes push sleep physiology in opposing directions. Stimulation of one class of serotonin receptors appears to increase deep slow-wave activity during non-REM sleep, while stimulation of another class decreases it.¹⁴ Meanwhile, polysomnographic studies of patients taking citalopram have found that the drug does not dramatically alter the intensity of deep sleep itself, as measured by delta-wave power, even though it reshapes other aspects of sleep structure.¹⁵

In practical terms, this means citalopram substantially rearranges the stages and timing of your sleep without necessarily destroying the deepest, most physically restorative phase. You may spend less time dreaming and more time in lighter sleep stages, and you may wake up more often during the night, but the core deep-sleep component often holds up reasonably well. That is a meaningful distinction: someone who hears “citalopram disrupts sleep” might imagine they are losing the most important kind of sleep, when the reality is more nuanced. The disruption is real but lopsided, falling most heavily on REM and sleep continuity rather than on deep slow-wave sleep.