People battling with insomnia have difficulty falling or staying asleep or experience non-restorative sleep. 20 - 35 % of the general population report that they battle with insomnia symptoms. Researchers have shown that insomnia can negatively affect both your physical and mental health (e.g. increase your risk of depression and/or anxiety disorders).1

Depression is a common mental health condition that ranges from a few depressive symptoms to major depression.1

Symptoms of depression include2:

  • Persistent sad, low, or irritable mood
  • Feelings of hopelessness, worthlessness, or guilt
  • Loss of interest or pleasure in activities
  • Decreased energy and extreme tiredness (fatigue)
  • Difficulty concentrating
  • Low appetite or overeating
  • Thoughts of death or suicide
  • Insomnia, waking up too early, or oversleeping

Depression and sleep issues (e.g. insomnia) have a reciprocal relationship. This means that having depression makes a person more likely to experience sleep problems and that poor sleep can lead to the development of depression.2

How changes to your sleep architecture can affect your mood5

Over the course of the night, your total sleep is made up of 4 – 6 sleep cycles. Each sleep cycle consists of 4 stages: one for rapid eye movement (REM) sleep and three that form part of non-rapid eye movement (NREM) sleep.6

The breakdown of a person’s sleep into various cycles and stages is referred to as sleep architecture.6

Deep sleep (stage 3) is critical to restorative sleep. It allows for growth and for your body to recover from the day.6

During REM sleep, your brain activity ramps up, close to levels seen when you are awake. This can cause you to experience vivid dreams. REM sleep is also essential for maintaining cognitive functions (e.g. memory, learning and creativity) and for the reprocessing and consolidation of emotional experiences in the limbic system of your brain.5,6

Arousal (becoming more alert to an extent during a sleep cycle) occurs due to changes in your brain wave activity. It does not necessarily mean that you wake up, but could just mean a shift out of deep sleep to lighter sleep, from which it is easier to be woken up from. Frequent arousals can however lead to unstable or fragmented (repeated interruptions) sleep architecture.5,7

Excessive arousal and repeated interruptions (fragmentation) to REM sleep, which occurs in both insomnia and depression, can negatively affect how your brain regulates your emotions (reducing its ability to eliminate negative emotions).5

Speak to your doctor2

If you’re battling with sleep problems like insomnia, and troubled feelings or low mood, speak to your doctor about the treatment options that are available to you. Research has shown that treating insomnia may lessen depression severity, hasten recovery and lower relapse rates.2,4


We’ve created a booklet filled with useful tips to help you manage your insomnia.8

In preparing this article, every effort has been made to provide an objective overview. The content contained in this article contains medical or health sciences information as per cited articles for public information. The content of this article has been initiated and is brought to you by Sanofi South Africa.

  1. Li L, Wu C, Gan Y, et al. Insomnia and the risk of depression: a meta-analysis of prospective cohort studies. BMC Psychiatry 2016;16(375).
  2. Newsom R. Depression and sleep. 08 August 2023. Sleep Foundation. Available online at [Accessed 21 August 2023].
  3. Khurshid KA. Comorbid insomnia and psychiatric disorders: An update. Innov Clin Neurosci 2018;15(3-4):28-32.
  4. Franzen PL, Buysse DJ. Sleep disturbances and depression: risk relationships for subsequent depression and therapeutic implications. Dialogues Clin Neurosci 2008;10:473-481.
  5. Wu D, Tong M, Ji Y, et al. REM sleep fragmentation in patients with short-term insomnia is associated with higher BDI scores. Front Psychiatry 2021;12(733998). doi:10.3389/fpsyt.2021.733998.
  6. Suni E. Stages of sleep. 08 August 2023. Sleep Foundation. Available online at [Accessed 21 August 2023].
  7. Peters B. Arousal during the stages of sleep. 28 April 2022. Verywell Health. Available online at [Accessed 21 August 2023].
  8. Tips to help you overcome insomnia and get the sleep you need. Patient resource. Sanofi. MAT-ZA-2100751-1.0-07/2021.