How Do Antidepressants Affect Sleep?

If you’re depressed, one of the ways you probably know it is because your sleep cycle has changed. You might go from sleeping 8 hours a night to sleeping 11. You might go from being able to fall asleep easily to tossing and turning until 1 a.m.. You may find yourself waking with the birds instead of with your alarm clock. You may find yourself dreaming more or not at all.

In short, any change to your sleep pattern is possible thanks to depression. And all these sleep changes generally lead to increase daytime fatigue and a worsening of depression symptoms.

And these sleep pattern changes are because many of the chemicals in our brain that affect mood also affect sleep. For example, serotonin and norepinephrine, two neurotransmitters commonly targeted by antidepressants, play a critical role in suppressing rapid eye movement (REM) sleep (when you dream).

And it would be great if the antidepressants people took also worked to help their sleep cycle problems. Unfortunately, many antidepressants do just the opposite.

Tricyclic Antidepressants and Sleep

Tricyclic antidepressants (TCAs) are a heterogeneous bunch so they don’t all affect the brain, or sleep, in the same way. Generally, TCAs act to inhibit the reuptake of both serotonin and norepinephrine but individual TCAs may be found as sedating (helpful for insomnia) or activating (helpful for daytime lethargy). Many TCAs markedly supress REM sleep which inhibits dreaming and dream-vividness.

According to an article, The Effects of Antidepressants on Sleep, in Psychiatric Times by Andrew Winokur, MD, PhD and Nicholas DeMartinis, MD examples include:

• Doxepin: the most notable example as being helpful for treatment of insomnia. This drug, in low doses, is now prescribed under the brand name Silenor for the treatment of primary insomnia.
• Amitriptyline: may be useful in patients who have insomnia.
• Desipramine: activating, and has been shown to increase the time it takes to get to sleep (sleep onset latency), decrease sleep efficiency and increase the number of awakenings.

Monoamine Oxidase Inhibitors and Sleep

Monoamine oxidase inhibitors (MAOIs) increase the concentration of serotonin, dopamine, and norepinephrine. This type of antidepressant has been shown particularly beneficial in the treatment of what’s known as “atypical” depression. Atypical depression includes the symptoms of oversleeping, apathy and low energy.

According to Dr. Winokur and Dr. DeMartinis, examples include:

• Tranylcypromine: chemically related to amphetamine, this drug tends to be activating and supress REM sleep. Tranylcypromine increases the time it takes to get to sleep and awakenings during sleep.
• Phenelzine: may be less activating than tranylcypromine but still supresses REM sleep.

Select Serotonin Reuptake Inhibitors and Sleep

The most common type of modern antidepressant, select serotonin reuptake inhibitors (SSRIs) enhance the activity of serotonin in the brain and are known to supress REM sleep. Because different SSRIs work on serotonin differently, individual patients experience opposite reactions—both activation and sedation—sometimes from the same drug. As such it’s difficult to say what any one drug in this class will do to the sleep architecture of any individual, but many times SSRIs have a negative effect on sleep.

Select Serotonin Norepinephrine Reuptake Inhibitors and Sleep

As the name implies, select serotonin norepinephrine reuptake inhibitors (SNRIs) affect both serotonin and norepinephrine. Little study on this class of drugs has been done but they appear to show similar problems in affecting sleep as SSRIs.

Atypical Antidepressants and Sleep

Many antidepressants don’t fall neatly into the above categories and these are simply known as atypical antidepressants. They work in different ways and have divergent effects on sleep. Dr. Winokur and Dr. DeMartinis note:

• Trazodone: was notable for its daytime drowsiness when used as an antidepressant, but when the dosage is scaled back and it’s used as an adjunct, this drug can improve the symptoms of insomnia while not causing daytime problems. In studies, trazodone increased total sleep time, decreased wakefulness during sleep and exerted minimal effect on REM sleep.
• Mirtazapine: depressed patients with insomnia reported getting to sleep more quickly and sleeping longer overall. There is little evidence than mirtazapine supresses REM sleep. Daytime drowsiness may be a concern for some people.
• Bupropion: may increase insomnia and increase REM sleep time.

Antidepressant Sleep Profile

Sleep profile can help guide a patient and clinician towards an antidepressant choice, but even if sleep issues present themselves, there are additional ways to handle them including lifestyle changes and additional medications.