What is the effect of serotonin excess and deficiency on sleep?

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Last updated: May 30, 2025View editorial policy

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From the Research

Serotonin has a complex impact on sleep quality, and both excess and deficiency can disrupt normal sleep patterns, with the most recent study suggesting that serotonergic signaling may influence quality of life, depression, and insomnia in obstructive sleep apnea patients 1. The relationship between serotonin and sleep is multifaceted, involving the promotion of wakefulness and the production of sleep-inducing chemicals.

  • Excess serotonin, which may occur with certain medications like SSRIs or MAOIs, can cause insomnia, restlessness, and reduced REM sleep, as it keeps the brain in an overly alert state.
  • Conversely, serotonin deficiency can lead to poor sleep quality, difficulty falling asleep, and frequent nighttime awakenings. This deficiency may be addressed through medications that increase serotonin levels, such as trazodone or low-dose mirtazapine, with dosages ranging from 25-100mg for trazodone and 7.5-15mg for mirtazapine, taken before bedtime 1. Lifestyle modifications can also help regulate serotonin levels, including:
  • Regular exercise
  • Exposure to natural light during daytime
  • Consuming foods rich in tryptophan, such as turkey, eggs, and cheese
  • Maintaining consistent sleep schedules The most recent study, published in 2025, found that serotonergic signaling may influence quality of life, depression, and insomnia in obstructive sleep apnea patients, highlighting the importance of considering serotonin's role in sleep disorders 1. In contrast to older studies, which suggested that serotonin was associated with the initiation and maintenance of sleep 2, or that serotonergic neurons played a role in inhibiting sleep 3, the most recent study provides more insight into the complex relationship between serotonin and sleep. Additionally, a 2021 study found that the use of selective serotonin reuptake inhibitors may be associated with impaired breathing and worse nocturnal oxygen saturation in individuals with depressive disorders and sleep complaints 4. However, the most recent and highest-quality study, published in 2025, takes precedence in guiding clinical decision-making, and serotonin's impact on sleep should be considered in the context of individual patient needs and medical history, with a focus on promoting optimal sleep quality and overall well-being 1.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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