By Dr. David Woo - July 27, 2020

Fatigue is one of the most common symptoms of depression, affecting up to 90% of people diagnosed with depression, and can be one of the primary reasons depressed patients seek help. (1,2) But why does depression make you so tired?

Depression Affects Neurotransmitters That Regulate Sleep

Depression is a complex condition that can develop for many reasons. One known contributing factor to depression is an imbalance of certain neurotransmitters. Neurotransmitters are chemicals that allow nerve cells to communicate with each other and help regulate numerous functions in the body, including sleep. 

Dopamine and serotonin are two neurotransmitters that regulate the body’s sleep/wake cycle (also referred to as circadian rhythm) and are affected by depression. Dopamine is responsible for feelings of wakefulness and serotonin induces sleep. Low serotonin levels in the brain are linked to less restful sleep. (3,4)

Imbalances in these hormones may explain why some people with depression tend to sleep too much (hypersomnia), while others have trouble sleeping. 

Depression and Lack of Sleep Can Become a Cycle

Fatigue is more likely to be a symptom than a cause of depression. However, once someone has been diagnosed with depression, lack of sleep and bouts of depression can become cyclical. Researchers know that insomnia (difficulty falling and staying asleep) in people who do not have depression can increase the risk of developing depression, and lack of sleep in patients who have achieved remission can increase the risk of depression relapse. (2) Patients who see an improvement in symptoms, but do not achieve remission, are also more likely to report feeling fatigued. (5)

Some Antidepressants Can Cause Fatigue

Some antidepressants, including SSRIs and SNRIs, are considered stimulating antidepressants and can disturb sleep and cause fatigue. Your doctor may instruct you to take your medication in the morning to avoid any problems getting a good night’s sleep. (6)

Not all antidepressants affect sleep quality. If you’re currently taking an antidepressant and are having trouble sleeping, talk to your doctor. They may lower your dosage, add a low-dose sedating antidepressant that may help you sleep, suggest that you try a different antidepressant, or recommend an alternative depression treatment. (7)

How to Cope With Depression Fatigue

• Exercise: Exercise may seem like a counterintuitive answer to sleeping well, but one analysis of various studies found that doing over 20 minutes of low to moderate-intensity exercise can increase energy and reduce fatigue. (8)
• Establish a sleep routine: A routine can help train your body for bedtime. For example, stick to a schedule (go to bed and wake up at the same time every day) and have a special bedtime ritual that can help you relax before trying to sleep. 
• Consider TMS: If you’re currently taking antidepressants and have noticed a decline in sleep quality, talk to your doctor about trying an alternative depression treatment, like transcranial magnetic stimulation (TMS). TMS is a non-medication depression treatment that may actually improve sleep.

Insomnia and fatigue can be destructive to your daily life and your health. If you’ve been diagnosed with depression and are struggling with fatigue, talk to your doctor. If you’re currently taking antidepressants and are interested in learning about alternative depression treatments, like TMS and how it can help patients with depression, visit our website. 

Resources:

1. Ghanean H, Ceniti AK, and Kennedy SH. Fatigue in Patients With Major Depressive Disorder: Prevalence, Burden and Pharmacological Approaches to Management. CNS Drugs. 2018;32(1):65-74. Link. Accessed July 09, 2020. 

2. Nutt D, Wilson S, and Paterson L. Sleep disorders as core symptoms of depression. Dialogues Clin Neurosci. 2008;10(3):329-336. Link. Accessed July 14, 2020.

3. Oikonomou G, Altermatt M, Zhang R, Coughlin GM, Montz C, Gradinaru V, Prober DA. The Serotonergic Raphe Promote Sleep in Zebrafish and Mice. Neuron. 2019;103(4):686-701. Link. Accessed July 14, 2020.

4. California Institute of Technology. “Settling the debate on serotonin’s role in sleep: The brain chemical is necessary to get enough sleep.” ScienceDaily. Published June 24, 2019. Link. Accessed July 15, 2020.

5. Targum SD, Fava M. Fatigue as a residual symptom of depression. Innov Clin Neurosci. 2011;8(10):40-43. Link. Accessed July 13, 2020.

6. Wichniak A, Wierzbicka A, Walęcka M, and Jernajczyk W. Effects of Antidepressants on Sleep. Curr Psychiatry Rep. 2017;19(9):63. Link. Accessed July 09, 2020.

7. Clark MS, Smith PO, Jamieson B. Antidepressants for the Treatment of Insomnia in Patients with Depression. Am Fam Physician. 2011;84(9). Link. Accessed July 13, 2020. 

8. Loy BD, O’Conner PJ, Dishman RK. The effect of a single bout of exercise on energy and fatigue states: a systematic review and meta-analysis. Fatigue: Biomedicine, Health & Behavior. 2013;1(4):223-242. Link. Accessed July 14, 2020.

Dr. David Woo

Dr. Woo has been seeing patients in private practice since 2002, always with the goals of combining evidence-based medicine with psychodynamic psychotherapy and collaborating with other mental health professionals to ensure the best possible outcomes for his patients. He has been certified to administer TMS at his practice since 2017. His greatest clinical interests include helping patients suffering from depression, anxiety, and obsessive compulsive disorder.