Fatigue

Reviewed by Shariq Refai, MD, MBA·Updated March 15, 2026·About 3 minutes

Canonical definition at Shrinktionary. This entry adds the depression-specific angle.

Sources

American Psychiatric Association. DSM-5-TR.
Ferentinos P, et al. Fatigue and somatic anxiety in patients with major depressive disorder. Eur Psychiatry. 2011.
Targum SD, Fava M. Fatigue as a residual symptom of depression. Innov Clin Neurosci. 2011.
Noetel M, Sanders T, Gallardo-Gómez D, et al. Effect of exercise for depression: systematic review and network meta-analysis of randomised controlled trials. BMJ. 2024.

Primary source: MedlinePlus: Depression (U.S. National Library of Medicine).

Frequently asked questions

Why does depression cause fatigue?

Fatigue in depression involves changes in sleep architecture, circadian rhythm, appetite and nutrition, activity level, and inflammatory signaling. The result is a heavy, body-deep tiredness that sleep doesn't fix. About 90 percent of patients with major depression report meaningful fatigue.

How is depressive fatigue different from ordinary tiredness?

Ordinary tiredness improves with rest. The fatigue of depression often doesn't. Patients describe waking unrefreshed, feeling effort in routine tasks, and losing the sense that activity is restorative.

What medical conditions can mimic depressive fatigue?

Hypothyroidism, anemia, vitamin B12 or vitamin D deficiency, obstructive sleep apnea, diabetes, chronic infections, and several medications (including some for blood pressure and allergies) can cause fatigue and low mood that overlap with depression. Basic blood work and a sleep history are part of a complete evaluation.

What helps fatigue in depression?

Treating the underlying depression is the main lever. Sleep regularity, light morning exposure, and graded physical activity have evidence as adjuncts. Bupropion and certain SNRIs are sometimes chosen when fatigue and low energy are prominent. Modafinil is sometimes used as an add-on in selected cases.

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Last reviewed March 15, 2026.

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